NWS Radar & Severe Weather Statements

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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sun Dec 18, 2016 2:30 pm

...A Flash Freeze is Expected Across the Region This Afternoon and Evening...

An arctic cold front will cross the area late this morning into this afternoon. Behind this front, steadier rains will taper to scattered snow showers as temperatures fall sharply into the 20s by this afternoon, and into the teens by early evening. This will result in a rapid freeze of any lingering water on area roads, parking lots and sidewalks with potential icy conditions developing.

Precautionary/Preparedness Actions...
Untreated surfaces may become extremely slippery and offer little or no traction. Reduced speeds and greater distance between vehicles is advised.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Wed Dec 28, 2016 6:08 pm

Image

WINTER STORM WARNING
WINTER WEATHER ADVISORY

.SYNOPSIS...
High pressure over New England tonight moves offshore by morning. Low pressure develops along the Mid-Atlantic coast Thursday, and rapidly intensifies as it crosses Eastern Massachusetts Thursday evening, bringing heavy snow well inland and mainly rain along
the coastal plain. Dry, windy and colder conditions are expected Friday into Saturday. Another low pressure may bring a period of light rain and/or snow to the region late Saturday afternoon into Saturday night. Warmer and more unsettled weather expected toward the middle of next week.

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Clouds have been slow to break, but that should be the trend this evening. The back edge of the cover over New York and PA extrapolates to Southern New England between 7 and 10 pm.

High pressure over NY and PA will move overhead tonight, bringing light winds. Temperatures upstream under the high reached down to the 20s this morning, and this looks fine for our area tonight.

Mid and high clouds will start increasing later tonight in advance of the next storm.

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Northern stream trough digging over the Midwest will become negatively tilted as it moves over the Northeast USA. A 150-knot upper jet runs through the base of the trough Thursday morning, supporting the coastal formation.

Moisture in the column is focused west of New England at 12Z but slides east during the morning. All operational models show measurable pcpn west of the NY/New England border. So expect the precip to begin from west to east during the morning hours.

Best dynamics from the upper jet sets up over our area during the afternoon and moves east of us early at night. This will support strong upward motion. Where the pcpn is snow, this will mean bands of heavy snow.

The various models agree on the general scenario of the coastal low moving up past New England. They continue to disagree on the track of the low center. The GFS brings it across RI and Eastern MA just west of Boston while the ECMWF tracks from the benchmark to just outside of Cape Cod to the Maine coast. The GFS is a
warmer solution with the rain/snow line farther almost to the Berkshires while the ECMWF would bring it to Worcester and the Merrimack Valley. We are using a solution closer to the ECMWF regarding the rain/snow line, but the differences lead to less confidence.

We will maintain the Winter Storm Warning in Western and North Central MA with small adjustment of snow amounts. We will convert the remaining Winter Storm Watch to a Winter Weather Advisory. Areas south and east...the coastal plain including Boston and Providence...may start as snow but should quickly change to rain with rain for most of the storm.

The other concern will be strong winds. With a deepening low center as it crosses our area, there is concern for strong low level winds being brought to the surface. West winds trailing the storm will have speeds of 45-50 knots at 2000-4000 feet. This means strong wind gusts for Thursday night. A Wind Advisory will likely be needed for portions of Eastern MA and RI for Thursday night.

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights...
* Cold New Year`s Eve, with a mix of light rain and/or snow
* Milder temperatures return early next week, with the chance for more unsettled conditions

Overview...

Latest guidance package continues to advertise a a fairly
progressive flow developing over the northern USA this weekend into early next week. Eventually, a deep mid level trough will slowly move east enough to place southern New England into the path of a series of low pressures toward mid week. As typical for
this time frame, while there is good agreement on the overall trends, there are timing and intensity issues to contend with. Will favor a consensus approach, to smooth over the less predictable details.

Details...

Friday through Saturday...Will see strong W-NW wind gusts along the coasts, particularly across eastern MA, Friday morning into midday as the storm exits to Maine. Will likely need wind advisories for a time. May see some lingering snow showers across the east slopes of the Berkshires, Central New England, and into Maine, through Friday afternoon. Will see partly cloudy skies on average, though clouds again will linger across the region into early Saturday.

A ridge of high pressure passes through Saturday. This should mean dry weather and lower temperatures, particularly Friday night into Saturday.

Saturday night and Sunday...A clipper-like low pressure, and a mid level shortwave, will move from the Great Lakes into the Saint Lawrence River valley during this time. This will place southern New England on the relatively warmer side of the storm. Depending on the timing, and hence temperatures, looking at a mix of snow
and/or rain showers. With the storm so far from our region, not expecting much precipitation. Chances for precipitation gradually diminish during the first few hours of 2017, especially towards daybreak Sunday.

If anything, temperatures will rise during New Year`s Day, up to about 5 degrees above seasonal normals as high pressure moves across the region.

Monday into Wednesday...Large high pressure over southeast Canada slowly moves offshore. This will open the door for a low pressure to head northeast into the Great Lakes Tuesday, then offshore Wednesday. While moderately confident there will be a period of precipitation in southern New England during this time frame, have lower confidence on the timing. The fairly fast flow aloft would suggest a quicker timing. However, caution needs to be exercised with a downstream high pressure. The timing tends not to be as
quick at the surface.

&&
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Fri Jan 06, 2017 7:31 am

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Area Forecast Discussion
National Weather Service Taunton MA
420 AM EST Fri Jan 6 2017

.SYNOPSIS...
An offshore storm system will bring a period of light snow to much of the region this morning. The plowable snow should be confined to mainly the South Coast, Cape Cod and the Islands. Dry but cold weather returns this afternoon into Saturday morning. Another offshore low but likely more potent will bring the risk for more
significant snows to eastern Connecticut...Rhode Island and Eastern Massachusetts Saturday afternoon and evening. Then bitterly cold conditions overspread the area Sunday night into Monday morning. Temperatures begin to moderate next Tuesday and Wednesday.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
First system might be considered an appetizer for the main course Saturday and Saturday night. The surface low is relatively flat and quick moving. Nevertheless, model output depicts reasonably robust upward motion through a deep saturated layer within the favored dendritic growth zone. There is a reasonably deep frontogenetic forcing signal across SE New England, and we expect snow ratios to be in the vicinity of 15 to 1. Putting this together, we are anticipating 3 to 5 inches over the Cape and Islands and 2 to 4 inches along the south coast of Rhode Island. We anticipate a band
of 1 to 3 inches to the NW across central Rhode Island and SE Massachusetts NW of the Cape Cod Canal. There could be some ocean effect snow toward the latter part of the event late Friday mornng over the outer Cape and Nantucket but not the right wind flow for it to be a significant player for this first system.

The snow should come to an end across the Connecticut Valley by around mid morning and during the late morning across Rhode Island and central/eastern Massachusetts. The snow may linger to midday over the Cape and Islands with some flurries possible well into the afternoon over the outer Cape.

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
Some low clouds may persist across the outer Cape and Nantucket. Otherwise, expect mostly clear skies and fairly chilly temperatures in the teens across the interior and low to mid 20s along southeast coastal areas. Light WNW winds early tonight will gradually veer to become more northerly by daybreak.

.LONG TERM /SATURDAY THROUGH THURSDAY/...
* Latest trends suggest the risk for heavy snow Sat afternoon & evening to spread farther inland into eastern CT/RI & eastern MA including BOS-PVD corridor

* Temperatures colder than normal, with bitterly cold conditions Sunday night into early Monday, then moderating toward the middle of next week.

Saturday/Saturday Night
..

Model trends and preferences have all trended stronger with offshore cyclone and father northwest with its qpf shield. This seems reasonable given the trend toward a more amplified upper air pattern combined with a very
cold airmass on the front end of this system over the ocean including the Gulf Stream. This increased baroclinicity will result in a more rapid and stronger cyclogenesis offshore. The 00z GFS mass fields including moisture and instability are very similar to the
remainder of the 00z guid but for whatever reason GFS qpf is considerably less. Thus will follow a model blend of EC/NAM/UKMET and Rgem for Sat/Sat night storm.

Potential Snowfall...
More robust 00z guid supports comma head snows tracking across eastern CT/RI and eastern MA. Much of this strong lift appears to occur in the snow growth region which should result in snow ratios greater than climo...somewhere in the neighborhood of 15:1. Steadiest snow should come onshore to the south coast during the morning and then overspread the remainder of RI and eastern MA by afternoon. Heaviest snow likely falls Sat evening with snowfall rates of an
inch per hour possible. Snowfall will be enhanced across coastal Plymouth county and Cape Cod as NNE winds combine with very cold blyr over relatively warm SST to yield very steep low level lapse rates (-12C at 850 mb and +8C SST = Delta-T of 20C!) and ocean effect snow bands coming onshore into coastal Plymouth and Cape Cod.
This may also be the case for coastal Essex county (Cape Ann area) but to a lesser extent. Given the above reasoning there is a moderate risk (30-60% chance) for 6+ inches of snow across eastern CT/RI and eastern MA. Also a low risk of up to a foot of snow along coastal Plymouth county to Cape Cod and the Islands given
enhancement from ocean effect snows. System is somewhat progressive as mid levels remain open however strong forcing in comma-head/high snow ratios/ocean effect enhancement and potential mid level banding signature will offset progressive system.

Winter Storm Watches...

Given the upward trend in the 00z guid and reasoning mentioned above we`ll expand the winter storm watch into eastern CT, all of RI and eastern MA. This includes the Boston to Providence corridor and westward into the Worcester Hills. Forecast confidence in the watch
area is highest across coastal Plymouth county to Cape Cod and the islands, with most uncertainty along the western edge of the watch from the NH/MA border to the Worcester Hills into eastern CT.

Impacts...
Travel will become very difficult and dangerous Sat afternoon and evening as roads become snow covered and snowfall rates of an inch per hour (possibly greater) severely reduce vsby. Also across RI and eastern MA especially along the coastline strong NNE winds will
result in considerable blowing and drifting snow especially given it will be a dry/fluffy snow. Therefore given snowfall intensity and strong NNE winds near white out conditions are possible along the Plymouth coastline to Cape Cod and the islands.

Sunday...

Arctic short wave/front sweeps across the area during the afternoon. Models offering very steep low level lapse rates up to 8.5-9.0C/KM however moisture is marginal which may limit areal coverage of snow squalls. Nevertheless given the instability and shallow vigorous
forcing a few intense snow squalls are possible.

Sun night/Monday...
Piece of arctic airmass moves across the area with 850 mb temps lowering to -20C. Min temps will dip into the single digits across much of the area and low teens across Cape Cod and islands. Temps may be even colder given fresh new snow cover from Saturday`s
snowstorm. Winds become SW Monday but given subsidence inversion (limited blyr mixing) from 1040 mb high south of New England, max temps will only recover into the 20s during the afternoon...possibly lower 30s along the south coast including Cape Cod and islands.

Tuesday thru Thursday...

Moderating temps with a low probability of hitting 50 degs Wed per 00z EPS. However this change in airmass will be accompanied by a risk of showers Tue night and Wed.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Fri Jan 06, 2017 9:45 pm

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3 WARNINGS IN EFFECT, SEE DETAILS BELOW.

WINTER STORM WARNING IN EFFECT FROM 7 AM SATURDAY TO 1 AM EST SUNDAY...


THE NATIONAL WEATHER SERVICE IN UPTON, NY HAS ISSUED A WINTER STORM WARNING FOR SNOW...WHICH IS IN EFFECT FROM 7 AM SATURDAY TO 1 AM EST SUNDAY. THE WINTER STORM WATCH IS NO LONGER IN EFFECT.

* LOCATIONS...SOUTHEAST CONNECTICUT AND EASTERN LONG ISLAND.
* HAZARD TYPES...SNOW.
* SNOW ACCUMULATIONS...4 TO 8 INCHES.
* TIMING...DEVELOPING SATURDAY MORNING AND CONTINUING INTO THE EVENING.
* IMPACTS...HAZARDOUS TRAVEL DUE TO SNOW COVERED ROADS AND REDUCED VISIBILITIES.
* WINDS...NORTH 10 TO 20 MPH WITH GUSTS UP TO 25 MPH.
* VISIBILITIES...1/2SM OR LESS EXPECTED.
* TEMPERATURES...IN THE LOWER 20S.

WINTER STORM WARNING FROM 7 AM SATURDAY TO 1 AM EST SUNDAY...

* LOCATIONS...INCLUDE EAST COASTAL AND INTERIOR SOUTHEASTERN MASSACHUSETTS...ALL OF RHODE ISLAND INCLUDING BLOCK ISLAND.
* SNOW ACCUMULATION...OF 4 TO 8 INCHES.
* TIMING...SNOW OVERSPREADS THE AREA SATURDAY MORNING BECOMING HEAVY AT TIMES SATURDAY AFTERNOON AND EVENING...THEN TAPERING OFF LATE SATURDAY NIGHT.
* IMPACTS...UNTREATED ROADS WILL BECOME SNOW COVERED AND SLICK. VISIBILITY WILL BE REDUCED. TRAVEL WILL BECOME HAZARDOUS AS SNOW BECOMES HEAVY AT TIMES ALONG WITH GUSTY NORTHEAST WINDS RESULTING IN CONSIDERABLE BLOWING AND DRIFTING OF SNOW.
* WINDS...NORTH 10 TO 20 MPH WITH GUSTS UP TO 35 MPH.
* VISIBILITIES...ONE QUARTER MILE OR LESS AT TIMES.

WINTER STORM WARNING FROM 7 AM SATURDAY TO 4 AM EST SUNDAY...

* LOCATIONS...INCLUDE SOUTH AND SOUTHEAST COASTAL MASSACHUSETTS INCLUDING CAPE COD...MARTHAS VINEYARD...AND NANTUCKET.
* SNOW ACCUMULATION...OF 12 TO 16 INCHES.
* TIMING...SNOW OVERSPREADS THE AREA SATURDAY MORNING BECOMING HEAVY AT TIMES SATURDAY AFTERNOON AND EVENING...THEN TAPERING OFF LATE SATURDAY NIGHT.
* IMPACTS...NEAR BLIZZARD CONDITIONS ARE POSSIBLE AS SNOW BECOMES HEAVY AT TIMES ALONG WITH GUSTY NORTHEAST WINDS RESULTING IN CONSIDERABLE BLOWING AND DRIFTING OF SNOW WITH NEAR WHITE OUT CONDITIONS FORECAST. UNTREATED ROADS WILL BECOME SNOW COVERED AND SLICK. VISIBILITY WILL BE REDUCED. TRAVEL WILL BECOME HAZARDOUS.
* WINDS...NORTH 20 TO 30 MPH WITH GUSTS UP TO 40 MPH.
* VISIBILITIES...ONE QUARTER MILE OR LESS AT TIMES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING IS ISSUED WHEN AN AVERAGE SNOWFALL OF 6 INCHES OR MORE IS EXPECTED WITHIN A 12 HOUR PERIOD...OR FOR 8 INCHES OR MORE IN A 24 HOUR PERIOD.

TRAVEL WILL BE SLOW AT BEST ON WELL TREATED SURFACES...AND QUITE DIFFICULT ON UNTREATED SURFACES. ONLY TRAVEL IN AN EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
User avatar
Brother Al
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Production Year: 1984

Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sun Jan 22, 2017 3:44 pm

FLOOD WATCH
HIGH WIND WARNING
COASTAL FLOODING WARNING
NATIONAL WEATHER SERVICE
TAUNTON MA
1111 AM EST SUN JAN 22 2017

Image

...FLOOD WATCH REMAINS IN EFFECT FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING...
...HIGH WIND WARNING REMAINS IN EFFECT FROM 9 AM MONDAY TO 6 AM
EST TUESDAY...


...STRONG AND POTENTIALLY DAMAGING WINDS EARLY MONDAY THROUGH EARLY TUESDAY MORNING...
* TIMING
...WINDS COULD BEGIN GUSTING AS HIGH AS 45 MPH JUST BEFORE DAYBREAK MONDAY. THE STRONGEST WINDS ARE EXPECTED MONDAY AFTERNOON AND LATE EVENING.
* LOCATIONS...
IN CONNECTICUT

...SOUTHERN FAIRFIELD...SOUTHERN NEW HAVEN-SOUTHERN MIDDLESEX...SOUTHERN NEW LONDON....
IN RHODE ISLAND
...BLOCK ISLAND...SOUTHERN WASHINGTON AND SOUTHERN NEWPORT
IN MASSACHUSETTS
CAPE COD...MARTHAS VINEYARD...NANTUCKET...

* WINDS...EAST 30 TO 40 MPH WITH GUSTS UP TO 70 MPH.
* IMPACTS...STRONG EAST WINDS WILL BE CAPABLE OF DOWNING TREES AND POWER LINES MONDAY INTO EARLY TUESDAY MORNING. THE WINDS MAY ALSO CAUSE PROPERTY DAMAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
A HIGH WIND WARNING IS ISSUED WHEN SUSTAINED WINDS OF 40 MPH ARE EXPECTED FOR AT LEAST ONE HOUR...WITH GUSTS OF 58 MPH OR GREATER AT ANY TIME. DAMAGE TO TREES...POWER LINES...AND PROPERTY ARE POSSIBLE WITH WINDS OF THIS MAGNITUDE. POWER OUTAGES ARE LIKELY. TAKE ACTION TO SECURE LOOSE OUTDOOR OBJECTS.

THE FLOOD WATCH CONTINUES FOR

* PORTIONS OF MASSACHUSETTS AND RHODE ISLAND...INCLUDING THE FOLLOWING
IN MASSACHUSETTS

...BRISTOL...MIDDLESEX...ESSEX...NORFOLK...PLYMOUTH AND SUFFOLK COUNTIES.
IN RHODE ISLAND
...BRISTOL...KENT...NEWPORT...PROVIDENCE AND
WASHINGTON.

* FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING
* HEAVY RAIN IS EXPECTED MONDAY AFTERNOON THROUGH EARLY TUESDAY MORNING. MOST LOCATIONS CAN EXPECT BETWEEN 2 AND 3 INCHES OF RAIN.
* SIGNIFICANT FLOODING OF URBAN...POOR DRAINAGE AND LOW LYING AREAS IS THE GREATEST THREAT INCLUDING ROADS THAT TEND TO FLOOD IN HEAVY RAIN. SMALLER RIVERS AND STREAMS MAY ALSO FLOOD SURROUNDING AREAS. LARGER MAINSTEM RIVERS SHOULD REMAIN WITHIN THEIR BANKS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLOOD WATCH MEANS FLOODING IS POSSIBLE. IF YOU LIVE OR WORK IN AN AREA PRONE TO FLOODING...TAKE THE TIME NOW TO PROTECT ANY ITEMS THAT COULD BE DAMAGED BY FLOOD WATERS.

DRIVERS SHOULD BE PREPARED FOR SLOWER THAN USUAL COMMUTES MONDAY AFTERNOON AND POSSIBLY TUESDAY MORNING. KNOW ALTERNATE ROUTES IN CASE ROADS BECOME FLOODED. NEVER DRIVE THROUGH A FLOODED ROADWAY!
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
User avatar
Brother Al
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Production Year: 1984

Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Thu Feb 09, 2017 7:11 am

Image
Image

URGENT - WINTER WEATHER MESSAGE
National Weather Service Taunton MA
428 AM EST Thu Feb 9 2017


...BLIZZARD WARNING REMAINS IN EFFECT FROM 9 AM THIS MORNING TO 8 PM EST THIS EVENING...

* LOCATIONS
...Suffolk County, Eastern Plymouth County...Cape Cod...Marthas Vineyard...Nantucket and Block Island.

* HAZARD TYPES...Heavy snow...strong to damaging winds and Blizzard conditions.
* ACCUMULATIONS...Snow accumulation of 12 to 16 inches.
* TIMING...Precipitation will overspread the region between 6 and 9 am this morning and may begin as a brief period of rain. Any rain will change to snow by late morning. The snow will then fall heavy at times this afternoon before tapering off to snow showers this evening.
* IMPACTS...Heavy snow and strong to damaging winds will result in blizzard conditions this afternoon and early evening. Intense snowfall rates of 2 to 3 inches per hour will be possible at times this afternoon. Strong winds will create blowing and drifting snow and near-white out conditions at times. Travel is not recommended this afternoon and evening. In addition strong to damaging winds may result in isolated power outages.
* WINDS...Northeast 30 to 40 mph with gusts up to 65 mph.
* VISIBILITIES...One quarter mile to Zero, Whiteout Conditions.
* TEMPURATURES...In the upper 20s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Blizzard Warning is issued when sustained winds or frequent gusts over 35 mph are expected with considerable falling and/or blowing snow. Visibilities will become poor with whiteout conditions at times. Those venturing outdoors may become lost or disoriented. So persons in the warning area are strongly advised to stay indoors.

COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 8 AM THIS MORNING TO 1 PM EST THIS AFTERNOON...

* LOCATION...MAINE, NEW HAMPSHIRE, AND MASSACHUSETTS

EAST AND NORTHEAST FACING SHORELINES FROM MAINE TO PLYMOUTH MA. CAPE COD SANDWICH TO DENNIS, CHATHAM, NANTUCKET, AND MARTHA`S VINEYARD.
* TIDAL DEPARTURE...THE TIDE WILL RUN GENERALLY 1 TO 1.5 FEET ABOVE NORMAL AROUND THE TIME OF THE THURSDAY MID TO LATE MORNING HIGH TIDE.
* TIMING...AROUND THE TIME OF THE THURSDAY MID TO LATE MORNING HIGH TIDE. BECAUSE WAVES AND SURGE WILL BE INCREASING THROUGH THE MORNING, POCKETS OF MINOR COASTAL FLOODING MAY LINGER FOR A COUPLE HOURS OR SO AFTER THE TIME OF HIGH TIDE. THERE IS ALSO A RISK OF SOME SPLASHOVER ALONG THE SHORELINE SOUTH OF BOSTON, INCLUDING THE NORTH SIDE OF CAPE COD, AROUND THE TIME OF THE THURSDAY EVENING HIGH TIDE.
* COASTAL FLOOD IMPACTS...SOME VULNERABLE SHORE ROADS WILL LIKELY BECOME FLOODED WITH UP TO A FOOT OF WATER INUNDATION POSSIBLE. THERE MAY BE FLOODING OF A FEW VULNERABLE BASEMENTS AS WELL. A FEW ROADS MAY NEED TO BE CLOSED ABOUT THE TIME OF THE HIGH TIDE.
* SHORELINE IMPACTS...SOME SAND AND COBBLE DEBRIS MAY BE WASHED ONTO VULNERABLE SHORE ROADS DURING THE THURSDAY MORNING HIGH TIDE. IN ADDITION, POCKETS OF EROSION ARE LIKELY FOR BOTH THE THURSDAY MORNING AND THURSDAY EVENING HIGH TIDES INCLUDING THE OCEAN SIDE OF CAPE COD AND THE EAST SIDE OF NANTUCKET.


Area Forecast Discussion
National Weather Service Taunton MA
411 AM EST Thu Feb 9 2017

.SYNOPSIS...
A major winter storm will bring heavy snow to the entire region with Blizzard conditions across southeast Massachusetts Today. High pressure builds in with drier colder air tonight through Friday night. Two weather systems then affect us over the weekend, bringing a chance of snow Saturday and rain or snow Sunday.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
4 AM UPDATE...

*** A Major Winter Storm Impacts The Entire Region Today With Heavy Snow And Blizzard Conditions Across Southeast Massachusetts ***


00z model guidance has trended stronger with coastal storm impacting the region today, this includes heavier snowfall and stronger winds than previous runs. Thus have trended the forecast in this direction.

Potent short wave trough across the TN valley early this morning has induced a frontal wave over VA. As this mid level trough amplifies and the frontal wave interacts with a very baroclinic environment south of New England, explosive cyclogenesis occurs later this morning and afternoon as surface low tracks from the DE coast at 12z
to near the 40N/70W benchmark at 18z. During this time the low bombs with a 14 mb pressure drop from 993 to 979 in 6 hrs!

As mid level heights crash the open wave at H7 becomes a closed circulation directly over southern New England. A strong mid level deformation zone sets up and with heights crashing mid level lapse rates steepen in a saturated environment. This will set the stage
for intense snowfall rates of 2-4" per hour at times along with a low risk of thundersnow. Despite this system remaining progressive with a duration limited to about 12 hrs...intense snowfall rates will result in a fairly blockbuster/high end snowstorm. The only
uncertainty with the forecast is pinpointing exactly where the heaviest snow bands set up, which is typically a challenge given the mesoscale nature of these snow bands.

Timing and Snowfall Intensity...
Good model agreement on snow overspreading the region this morning between 5 am and 8 am from west to east. Snow quickly becomes moderate to heavy shortly after the onset. Precip will likely begin as rain or a mix of rain and snow at the start across the south
coast of MA and RI including Cape Cod, before changing to all snow by midday or so. Period of heaviest snow appears to occur from about 9 am to about noon across CT and western-central MA. Farther east into RI and eastern MA heaviest snow will fall from about noon to 4 pm. As mentioned above intense snowfall rates of 2-4" per hour will develop during this time. Always difficult to pinpoint exactly where these mesoscale bands setup. Typically a favorable location is in the northern-northwest semi-circle of the H7 low which develops
across RI and eastern MA. In fact the new 03z SREF has probabilites up to 60% for hourly snowfall rates of 3" across eastern CT-RI- southeast MA...possibly clipping the Greater Boston area. Thus increased confidence in these intense snowfall bands to develop from eastern CT into RI and eastern MA...extending back into the Worcester Hills. It`s during this time that travel will become extremely dangerous with snowfall rates of 2-4" per hour resulting in near white out conditions.

Snowfall Accumulations...
Given 00z models have trended upward with widespread 1.0+" of qpf and both global and high res guid approaching 2" of qpf along the south coast of MA and RI. This supports a large swath of 12-18"
snowfall across the region. 18" amounts will be tied to the location of where the stronger snow bands set up with the favorable locations for this across eastern CT-RI and eastern MA extending back into the
Worcester Hills. A secondary max of 18" is possible along the coast of Plymouth county and the upper Cape where OES contributions increase late this afternoon and evening as much colder air streams across the relatively warm ocean waters on gusty NNE winds. Isolated
20" amounts not out of the question especially if thundersnow materializes.

Strong to Damaging Wind Potential...
00z model guidance has also trended upward regarding strong to damaging winds as coastal wave bombs to a sub 980 mb low as it tracks near the 40N/70W benchmark. All guid including model soundings support a period of NNE winds up to 60 mph from 1 pm to 7
pm across the Cape and Islands. Blizzard warnings across this area incorporate the risk for 60 mph wind gusts. The combination of winds of this magnitude combined with wet snow for a period of time today
there is a low risk for isolated power outages across Cape Cod, the islands and coastal Plymouth county. These winds combined with near zero visibility in heavy snow will result blizzard conditions along with
considerable blowing and drifting snow.

Headlines...
No changes to headlines over land. Only change was to increase snowfall totals and higher wind speeds for the Cape and Islands this afternoon and evening.

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
Tonight...

Snow...heavy at times lingers this evening across Cape Cod and Nantucket...then tapering off toward midnight. Elsewhere snow tapers off 4 pm to 7 pm from west to east. Despite snow ending gusty NNW winds will result in considerable blowing and drifting especially across RI and eastern MA where winds will be strongest. Very cold
air dives in on the backside of this departing coastal storm. Most locations dip into the single digits tonight but combined with gusty NNW winds, wind chills will be considerably colder.

LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights...

* Snow showers on Saturday from clipper system.
* Mixed precipitation event appears more likely Sun into Mon.
* Seasonable temperatures for early to mid next week.


Overview and model preferences...
Noting that synoptic scale pattern remains relatively unchanged through early next week. Following the trof associated with today`s storm, progressive pattern remains in place through the weekend even as wave with associated clipper moves through Sat. By late Sun into Mon, while there is good agreement on the
formation of a cutoff low pres at H5 but exactly where this sets up will impact thermal profiles associated with an initial inside runner. Beyond this, and because of the interactions with longwave trof across Labrador and Greenland, there is some question about how the pattern unfolds across the NE, as some are more arctic influenced while other solutions remain attached to the SE CONUS ridging. Once again, will lean more
heavily on ensemble means for this update, as they better account for thermal profile possibilities than any one deterministic model.

Details...
Fri...

Cold and dry with brief ridging of high pres. H92 temps warm from -18C at the lowest at 12Z to -14C by 00Z Sat. This will keep highs mainly in the 20s, possibly a few low 30s, exacerbated by new snowpack. Mins Fri night likely fall into the teens and could make the single digits except increasing low- mid clouds and a risk for early AM snowfall. Wind chills remain an issue, in the single digit below 0F to start the day, but even at peak heating they will struggle to reach the lower double digits above freezing. Wind gusts early 20-30 mph will gradually fade toward the end of the day as pres gradient slackens in response to peak ridging.

Sat into early Sun...
Still noting the passage of a modest clipper mainly across N New England late Sat and Sat night. Weak overrunning combined with PWATs near 0.75 inches suggest overall QPF values ranging between 0.1 and 0.3 inches. Initial low lvl thermal profiles support all snow, but H92 temps rise above 0F mainly S of the Mass Pike by late day, which could lead to some changing to rain
and overall lowering of SLRs even further N with the influence of warmer air. In fact, the omega associated with the warm advection is so light, it will likely be unable to override the warming. Therefore, maintain that any snow totals should remain at most low end Advisory levels, but most likely below. Temps closer to seasonal normals. Mainly upper 20s to upper 30s for highs, while lows drop into the 20s.

Late Sun into Mon...
As mentioned above, a deepening wave with dual origins in northern BC Provence and the eastern Pacific will gradually deepened to a full fledged cutoff across New England by early Mon morning. While initially, this suggests a parent inside-runner, there has been a significant trend in the formation of a secondary low near or even just off the SE Coast of New England. This suggests thermal profile changes are in play, initially warm enough for widespread rain. However, it could,
depending ultimately on the track of a secondary low, introduce freezing rain/sleet or even a full fledged change to snow before ending on Mon. In fact initial bufkit profiles already support this transition in areas such as the Worcester Hills and Berkshires. Too early to call based on complex interactions and mesoscale forcing. However with 1.00 to 1.50 inch PWATs and the
additional convergence/deformation provided by another low pres development could yield heavy rain or mixed precip it times early Mon. Will need to watch this given the risk for another round of wintry mix/snow for the early work week.

Tue...
Brief ridging will follow the strong secondary low pres exiting to the E. Ensemble mean thermal profiles suggest temps mainly near seasonal following this feature.

Wed and beyond...
If the suggested phasing of the trough from late weekend and longwave trough over Labrador/Greenland verifies, will need to watch for another cold storm system, however this requires all plays leading up to this point to work out as progged. Still with longwave trough upstream, will need to keep an eye on development for this period.
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Fri Feb 10, 2017 8:59 pm

Image

Area Forecast Discussion
National Weather Service Taunton MA
632 PM EST Fri Feb 10 2017

.SYNOPSIS
...
Powerful low pressure south of Nova Scotia will circulate dry but very cold air across New England today on gusty northwest winds. Our active weather pattern continues tonight as a warm front approaches the region and produces a period of light snow with 1 to 3 inches of accumulation likely into Saturday morning. Low pressure then brings a wintry mix of precipitation and heavy snow to the area Sunday into late Sunday night or Monday along with strong winds as low pressure intensifies rapidly east of Cape Cod. Dry weather likely returns Tuesday and then another chance of snow Wednesday and/or Thursday.

NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Forecast appears to be on track for this evening. High level clouds are beginning to push into the region ahead of approaching wave. Radar imagery shows precip still across upstate NY but will eventually move into the region with in the next 3-6 hours. Snowfall amounts look to be around 1-3 inches. Could see a few isolated 4 inches along the east slope of the Berks, either which way a snowy morning will be in store.

May have to watch lingering snow showers across the eastern coast line as low level moisture appears to get trapped within the inversion. This combined with a weakening inverted trof may result in snow showers into late Sat morning/early afternoon hours. Best place for this to occur is across northeastern MA.

Previous Discussion...
No major changes with the forecast for tonight. Still appears to be a good overrunning setup tonight as a warm front approaches our region. No real question on precipitation type, it will be a light snow. The most likely window for snowfall should start between 10 pm and 1 am, and end later Saturday morning. Most of the snow should fall tonight. Expecting a general 1 to 3 inches of snow, with locally higher amounts up to 4 inches possible. It`s marginal, so no Winter Weather Advisories have been issued.

SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Saturday...Precipitation gradually ends from west to east Saturday morning. Most of the region should be dry by mid morning. Developing south winds may be strong enough to push temperatures above freezing, which means the precipitation may end as a brief period of rain or a rain/snow mix towards the south coast of New England, particularly across Nantucket.

Not a big storm by any stretch but snow covered roads will result in slippery travel Saturday morning. Near normal temperatures.

Saturday night...
This is where the forecast starts getting tricky. Surface temperatures should be sufficiently cold at the surface to support snow across much of southern New England. One issue will be how quickly we can moisten the dendritic snow growth region, another will be low level temperatures above the ground.

The lack of moisture in the snow growth region might lead to a period of freezing rain or freezing drizzle early Sunday morning. The thermal profiles may also contribute to that potential. It`s also possible we could get a wintry mix across southern New England, with rain toward the coast and a snow/sleet mix farther inland.

LONG TERM /SUNDAY THROUGH FRIDAY/... Highlights...
* Intense coastal storm will lead to multi-hazard system occurring Sunday into Monday
* High pressure on Tuesday into Wednesday
* Low confidence on another coastal system Thursday into Friday

Pattern Overview..
.
12z Guidance is in general agreement for the medium range but begin to diverge for the long term. Building ridge across the northwest CONUS will keep New England in a trough pattern for the remainder of the period. Appears winter is here to stay. Attention first towards weak ridging on Sunday morning as dynamic shortwave moves over southern New England. This wave will develop and bomb out a surface low just to the east of the area. This system will result in several hazards for Sunday into Monday. Northwest flow aloft will continue across New England before another dynamic shortwave moves over the region. This is more uncertainty with this system, especially with the low level features. The GFS appears more progressive and to late to capture southern Plains surface low into a coastal storm, where the EC is more amplified resulting in coastal low pressure late Wed into Thursday. Ensembles are also indicating large spread so low confidence beyond Wednesday night and beyond.

Sunday into Monday...
** Heavy snowfall possible north of the Mass Pike
** Strong wind gusts across eastern Mass
** Coastal Flooding issues are possible especially near the Cape and Islands


Digging trough and closed upper level low will approach southern New England on Sunday/Monday. Ahead of this system, WAA will lead to overrunning Sunday morning resulting in wintry precip especially across CT/western MA.

As the system advances, both 500 mb and 700 mb closed low strengthens considerable, developing a surface low south of the region on Sunday. As upper level jet dynamics moves into the region, anticipate the surface low to bomb out east of southern New England by Sunday night. This system has some incredible dynamics and impressive low level baroclinic zone as well as a hint of rather extreme deepening with a tropopause fold. Still some difference in the placement of the low as the GFS is on the eastern side of the envelope, but both of the deterministic and ensemble guidance is pin-pointing this low to develop south of the region before strengthening east of the area by Sunday night/Monday morning.

Biggest question with this system is the thermal profiles. Placement of the low can change temperatures a few degrees which could result in different p-types. Consensus is snow north of the Pike for the event, with the potential for wintry mix across northern CT and into NW RI. Rain along the I-95 corridor towards the Cape and the Islands as the low moves eastward bringing in warmer air. As the low moves east of southern New England and strengthens considerably, appears that strong CAA will move-in collapsing the temperature profile and changing the p-type to all snow by Sunday night/Monday morning. Again the p-types can change in the coming days but this is general consensus as of now. Went ahead an issued a winter storm watch with surrounding WFOs. The watch is located where highest confidence of 6+ inches of snow could occur. There is the potential that the watch may be expanded if the thermals are cooler than currently advertised. Aside from the watch, winter weather advisories may be needed for snow, sleet, freezing rain or the combinations of the three. Still have a few more guidance cycles to determine this outcome.

As the surface low undergoes bomb cyclogenesis, the pressure gradient will tighten significantly. This will result in 925 mb LLJ reaching between 40-50 kts. Steep Lapse rates and good mixing will help bring these strong gusts down to the surface. Appears that locations across eastern MA has the best shot to see wind gusts near 40-50 mph. This will result in wind headlines as well as blowing and drifting snow on Monday.

Northerly to northeast winds on Monday will result in building seas and storm surge. This surge combined with the seas and wind gusts could result in minor to moderate coastal flooding across the northern shoreline of the Cape, Cape Ann and Nantucket. Coastal erosion is also possible.

Overall still some uncertainties with this system. However confidence is increasing in heavy snow north of the Pike and gusty winds across the east coastal MA. More details will be resolved in the upcoming forecast so stay tuned.


Tuesday and Wednesday...
Weak ridging aloft will yield to a break in the precipitation on Tuesday. Another weak wave will move through the area on Wednesday which could out put some showers across southern New England. Low confidence on Wednesday forecast as models are diverging on timing and strength.

Wednesday night into Thursday...
Lots of uncertainty with this system as the EC brings another impressive coastal storm to the region while the GFS is dry. Ensembles guidance in both the GEFS and ECENS are still all over the place as the potential outcomes to this system. Will need to watch this timeframe over the next several days to get a better idea of what could occur.
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sun Feb 12, 2017 10:33 am

Image

Area Forecast Discussion
National Weather Service Taunton MA
437 AM EST Sun Feb 12 2017

.SYNOPSIS...

Major coastal storm this afternoon through Monday evening...Hurricane Force Winds will be developing off the coast, at sea creating a very dangerous situation for seagoing vessels. Blizzard Watches, Warning, and Winter Syorm Warnings have been issued for most of New England as this complex 3 part Storm system develops.

.A strong low pressure system will develop in the Gulf of Maine this afternoon. Snow will begin this morning in Southern New England and progress up into ME by the afternoon and become heavy overnight. Snowfall rates of 2-3 inches per hour at times across portions of ME snd NH, with 1-2 inches per hour over portions of Mass are expected to lead to very hazardous travel conditions. Winds will increase through the overnight resulting in blizzard or near- blizzard conditions. In addition, some rain may mix in with the snow for a time on the coast Sunday afternoon and night, with the snow itself being heavy and wet. This in tandem with increasing winds may allow for power outages to occur. If blizzard conditions appear imminent for late Sunday night and Monday, a subsequent blizzard warning may be issued for portions of the coastal plain, from Cape Cod up into Downeast Maine, where winds will be highest.

Spotty light snow early this morning becomes a widespread steady snow this afternoon and heavy at times into early this evening. Snow may mix with or change to sleet and rain across RI and southeast MA. This is in response to rapidly intensifying low pressure off the coast of RI and MA which will bring significant snows and a possible wintry mix tonight into Monday. This intense low will bring a threat of damaging winds Monday especially to Cape Cod/Islands. High pressure and cold conditions prevail for Tuesday. Another storm system is possible Wednesday into Thursday. A renewed period of cold weather is forecast Friday into the weekend, however there is a moderating warmer trend into next week.

NEAR TERM /THROUGH MONDAY/...
430 AM update...
*** Snow heavy at times this afternoon & early evening followed by strong to damaging winds Mon along with potentially more snow later in the week***

Overview
...
Models in good agreement on the overall evolution of developing winter storm and especially snowfall potential on the front end today but then some uncertainty on how quickly and close storm intensifies to the region. This greatly impacts magnitude of strong winds Mon along with comma-head snows. Good agreement on low pressure intensifying tonight as it tracks from south of Long Island to near Nantucket at 06z to somewhere east of Cape Cod over western Georges Bank. Models struggling on how far southeast mid level low digs/tracks. This will impact the exact trajectory of the storm`s potent comma-head and associated heavy snow. In addition, the exact track, speed and amplification of the mid level circulation will also determine how quickly the surface low gets captured and briefly pulled back toward the eastern MA coastline. This directly impacts the pres gradient and associated wind field/damaging wind threat. GFS is most robust with entire system farther to the southwest than remainder of the guidance. ECMWF is in the middle of the pack. Both the EC and GFS have a sub 970 low over western Georges Bank Mon! Unfortunately southern New England is on the back edge of this potent developing Nor'Easter complex. Thus a small shift in storm track will have a huge impact on our forecast. Overall looking at a three part storm with snow heavy at times this afternoon then a bit of a lull tonight as dry slot overspreads the region, especially CT/RI and southeast MA, followed by comma-head snows Monday and strong to damaging winds across a large portion of coastal New England.

Timing...
Spotty light snow this morning then good agreement on a steady warm advection snow overspreading the region 9 am - 12 pm, then becoming heavy at times this afternoon as good forcing for ascent enters the snow growth region. Snowfall rates of 1-2" per hour are possible this afternoon. Warmer air begins to advect northward and will likely result in snow mixing with or changing to sleet and rain across RI and southeast MA. Thus highest totals will be across northern CT, Western and central/ northern MA, VT, NH, and ME. As for the Boston Metto, always a tricky forecast with marginal temps and onshore flow. However temps are fairly cold aloft and even by 00z tonight it`s about -4C at 850 over Boston. This combined with low pressure intensifying south of Long Island should result in pressure falls turning the wind to NNE. Thus leaning toward mostly all snow for much of the day. Blizzard to mear blizzard conditions expected for portions of Northeastern Maine.

Then tonight dry slot moves across the region and dries out the snow growth region, especially across CT/RI and southeast MA. Thus precip will likely transition to drizzle or low top showers. However interior CT/RI and southeast MA where temps will be at or below freezing could see a period of freezing drizzle/rain. North of the MA pike mid level dry air not as deep, which should support snow to continue and pile up.

Then beginning around daybreak Monday the surface low undergoes significant amplification in response to tremendous height falls. This results in a rapid developing comma-head into eastern MA and possibly westward into the Worcester Hills, eastern CT into RI. Thus the column becomes saturated again along with falling temps promoting another round of snow...possibly thundersnow given crashing heights/steepening mid level lapse rates. Beneath this comma-head a period of heavy snow is possible (greatest risk eastern and northeast MA into easten NH downeast and Northern ME) along with very strong to damaging winds resulting in near blizzard to blizzard conditions...

Snowfall amounts...
Highest snow totals 12-24 amounts look to generally remain along and north of the Mass turnpike into VT, NH, & ME, with portiond of Maine seeing the most. 8-12 for Western Mass through Worcester. Potential mixing but at least 8-12" expected in the Boston Metro. South of the MA pike for Eastern Mass into northern portions of CT/RI to the southern suburbs of Boston 6-12" remains likely. Then amounts taper downward to the south coast given snow changing to sleet and rain later today.

Winds....
Strongest winds will occur early Mon morning and continue through much of the daylight hours on Mon. Sustained winds of 20-30 mph with gusts to 40 mph are likely across most of the region. The only caveat will be areas along the E and SE coastlines, where 30-40 mph sustained winds will combine with occasional gusts 60+ mph early Monday morning and continuing into the daylight hours. Greatest risk for damaging winds will be from Cape Ann to Cape Cod and Nantucket. The blizzard Watch accounts for very strong winds. A second area of strong winds will be along the south coast. This area will be covered by a high wind watch given blizzard watches are not posted here.

Headlines...
Not have enough forecast confidence to upgrade the blizzard watch to a blizzard warning for southern coastal areas, given model spread in position/track and intensity of comma-head and surface low. However within the blizzard watch confidence is highest over coastal Essex county for blizzard conditions to be observed.

Uncertainty...
The greatest uncertainty in the forecast is how far inland does potent comma-head track and its duration. This will determine if blizzard conditions especially snowfall intensity are met Mon morning and afternoon across eastern MA. Given this uncertainty we did not upgrade blizzard watches to blizzard warnings.

Conversely do have increased forecast confidence on damaging winds across Cape Cod and possibly Cape Ann with gusts 50+ kt Monday morning and afternoon. Moderate to high probability for at least isolated power outages across this area.

As always, stay tuned to updates as forecast snowfall/sleet amounts as well as winds may be adjusted as we approach the onset of the storm.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...

*/ Highlights...
- Winter continues to prevail into early next week
- Monitoring the possibility of a late-week storm system
- Perhaps a significant warm-up into late February?

*/ Overview...

Big meltdown into late February? Above average temperature forecasts per CPC for the 8-14 day and 3-4 week period. This coinciding with quieting teleconnections as the stratospheric polar low shifts from N Canada into N Asia with the better component of cross-polar flow into W Europe. A weakening albeit shifting pattern to the E, quite a surprise to see ensemble means are 8-12 days out forecasting a +2SD H5 ridge pattern and a +20C H85 temperature anomaly for the February 20th to 22nd timeframe. Closely watch this going into late February.

But prior to will continue to see a favorable environment towards cyclogenesis across the NE CONUS. A psuedo rex block over the NE Atlantic acting to amplify and slow the upstream pattern, this as the phase 7 to 8 of the MJO invoking stronger high pressure over the ITCZ S of a dominant H5 Aleutian low acts to enhance the W to E Pacific jet thereby amplifying the +PNA over the Inter-Mountain W and subsequently lead to favorable troughing downstream.

Need to closely watch energy over the SW CONUS and its possible sub-tropical connection to the phase 7 to phase 8 of the MJO. In such a change of phase it has been noted there is a shift of stronger storm-type development transitioning from Miller A to Miller B, that is more preference of S-stream energy undergoing surface cyclogenesis rather than N-stream energy in vicinity of the NE CONUS. Grasping at the connection which is not entirely clear though the correlation is there per recent research.

Will keep the discussion short and brief below, focusing on targets of opportunity, particularly the storm for the late week period.

Monday night through Tuesday...
Winter weather persists. Strong NW flow initially, weakening with time. Mainly an isallobaric-gradient response, NW wind gusts 45-55 mph across the E-coast of MA, particularly Outer Cape and Nantucket. Winds quickly diminish into Tuesday morn as a ridge of high pressure builds into the region. Cold air advection having concluded, begin to see the airmass moderate with H925 temperatures warming up around -6 to -8C. Still a chilly day, also given a deep snow pack for some locations, though winds will be light. Lows overnight in the teens with wind chills roughly 5 to 10 degrees lower, highs around the low 30s with the mid-February sun angle, scattered stratocumulus.

Tuesday night through Thursday...
Continued uncertainty. Considerable spread in both deterministic and ensemble solutions. Perhaps a double-barrel low setup? Unclear as to whether N-stream polar-origin energy, rather moisture deprived, is fueled by S-stream energy out of the SW CONUS, whether the two come together and phase, or at the minimum interact. Some solutions hint at rapid cyclogenesis across the Gulf of Maine with trowaling / snow-banding across the backside of the system into E New England. Others have a sweeping cold front of light snow that pushes S-stream energy out to sea yielding a minimal impact for the region. Too early to say and maybe that is perhaps that we do not have good sampling of N- stream energy as it reside far N across the Arctic circle where info from satellites could be a bit more cumbersome. Will continue to monitor, but in the meantime hold with an ensemble mean forecast.

Some early forecast notes, leaning with a light snowfall event with higher amounts, perhaps advisory level, roughly 2 to 4 inches, over N/NE areas of MA. Be some precipitation-type issues along the coast with rain mixing in. Just an early guess with low confidence for now.

Thursday night and beyond...
Cold weather prevails. Behind the late week system and along the NE periphery of the building ridge across the Central CONUS, NW flow prevails that limits the SW approach of warmer air. High pressure and drier weather with what would appear to be a more seasonable to slightly above-seasonable temperature trend.
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sat Feb 25, 2017 1:07 pm

Image

Discussion
SPC AC 251613

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1013 AM CST Sat Feb 25 2017
Valid 251630Z - 261200Z


...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NY/ WESTERN NEW ENGLAND SOUTHWARD INTO NORTHEAST NC...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NY/MA/CT/VT SOUTHWARD INTO NC...

...SUMMARY
...
Thunderstorms capable of producing damaging winds, hail, ans a slight risk for a Tornado is forecast from New York and Western New England southward to North Carolina this afternoon.

A strong upper trough is rotating across the mid MS and OH valleys today, with the associated surface cold front extending from western NY/PA southward into western NC. A band of showers and isolated thunderstorms is present ahead of the front. This activity is moving into an area where breaks in the clouds and dewpoints in the 50s and 60s will yield marginal CAPE values and the potential for intensification. Strong winds aloft and focused forcing along the front, coupled with model consensus of a broken squall line later today, suggest a risk of a some storms intensifying to severe levels this afternoon. Fast-moving bowing structures capable of locally damaging winds would be the main threat, although hail, and possibly even a tornado may also occur in the strongest cores.
_______________________________________________________
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sun Feb 26, 2017 11:28 pm

Public Information Statement...CORRECTED
National Weather Service Taunton MA
650 PM EST Sun Feb 26 2017

...Tornado Confirmed Near Conway in Franklin County MA...

Location...Conway in Franklin County MA
Date...February 25 2017
Maximum EF-Scale Rating...EF1
Estimated Maximum Wind Speed...110 MPH

* The information in this statement is preliminary and subject to change pending final review of the event(s) and publication in NWS Storm Data.

...Summary...
The National Weather Service in Taunton MA has confirmed a tornado near Conway in Franklin County Taunton MA on February 25 2017.

The maximum estimated speed was 110 MPH, however most of the damage is estimated to have occurred with 80 to 100 MPH winds.
Most of the damage occurred in Conway, MA with a brief touchdown in Goshen, MA in Hampshire county.

A more complete report will be provided no later than noon Monday.

This information can also be found on our website at
weather.gov/box.

For reference...the Enhanced Fujita Scale classifies tornadoes
into the following categories:

EF0...wind speeds 65 to 85 mph.
EF1...wind speeds 86 to 110 mph.
EF2...wind speeds 111 to 135 mph.
EF3...wind speeds 136 to 165 mph.
EF4...wind speeds 166 to 200 mph.
EF5...wind speeds greater than 200 mph.

$$

Belk
For the latest updates...please visit our webpage at
www.weather.gov/boston

You can follow us on Facebook at
www.facebook.com/NWSBoston
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Thu Mar 09, 2017 10:04 am

Area Forecast Discussion
National Weather Service Taunton MA
601 AM EST Thu Mar 9 2017

.SYNOPSIS...

Dry but windy conditions today. A fast but potent wave of low pressure tracks south of the region Fri and likely delivers a plowable snowfall south of the Mass Pike with the heaviest amounts along the south coast. Arctic frontal passage Friday night could bring snow showers to the region. Near record breaking cold airmass returns for the weekend. Watching a coastal storm for Tuesday into Wednesday.

NEAR TERM /THROUGH TONIGHT/...

600 AM Update
...
No major changes to the forecast at this time. Dry weather is prevailing early this morning as shower activity has remained northward. Wind gusts are already beginning to increase above 20 to 25 MPH. This trend will increase once mixing begins after sunrise.

Previous Discussion...
Dry today with mostly sunny skies as the column remains quite dry, but some increasing mid/high clouds likely moving into western New Eng late in the day. Given 850 mb temps -6 to -8C this afternoon undercut MOS temps a few degrees with expected highs in the mid/upper 40s, but cooler higher elevations. A few locations in the coastal plain may reach 50.

The main weather story for today will be the strong west winds. Very steep low level lapse rates around dry adiabatic in the 1000-850 mb layer will promote excellent mixing with potential to mix winds down from the top of the mixed layer around or just above 850 mb. Gusts to 40-50 mph expected this morning into early afternoon today with strongest gusts over higher elevations. We will issue a wind advisory for all SNE. Winds will diminish mid/late afternoon.

.SHORT TERM /FRIDAY/...
*** Plowable snowfall south of the Mass Pike late tonight into Fri with heaviest accumulation near the south coast ***


Model guidance has trended north with heavier QPF with a more robust wave tracking near the benchmark. This in response to an amplifying mid level trof as potent northern stream shortwave digs SE from the Gt Lakes to the mid Atlc coast. There are timing differences with the heaviest snowfall but most of the guidance agrees on a period of heavy snow late tonight into Friday morning with a potentially significant impact on the morning commute, especially CT/RI and SE MA.

Strong thermal gradient north of the low supports strong low to mid level frontogenesis with resulting omega through the snow growth region. This will result in a west to east band of heavy snow which will likely be focused south of the Mass Pike and especially near the south coast. This will be a quick moving storm but potentially high impact with a period of snowfall rates of 1-2"/hour in the heaviest snow bands which may coincide with the Friday morning commute south of the Mass Pike to the south coast. Snow should taper off during Fri afternoon.

A sharp moisture gradient on the northern edge of the precip shield along with gradient in frontogenesis adds uncertainty to the forecast as there will likely be a sharp cutoff north of the heavy snow area. So any shift in this axis of deep layer forcing will have a significant impact on snow accum. Highest confidence of heavy snow is over the Cape/Islands where we will go with winter storm warnings for 6-8 inches accum. Expanded the watch across all RI and SE MA where potential for up to 6 inches with best chance along the south coast but will let day shift have a look at 12z guidance before making warning vs advisory decision. Winter weather advisories issued north and west of the watch area across N CT to central and eastern MA just south of the Mass Pike but confidence in snow amounts is lower near the Pike. Snowfall amounts will drop off north of the Pike with only minor accum near the NH border.

Confidence...
We have high confidence in warning level snow near the south coast but lower confidence further north. The guidance trended north with ECMWF, GFS and RGEM indicating 6 inches up to MA/CT/RI border and 8+ inches south coast. Forecast snow amounts are a bit more conservative as we leaned toward EPS snow probs which indicate best chance for 6 inches near the south coast and especially the Cape/Islands. However, if later guidance confirms this trend snow amounts will likely need to be increased.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...Highlights...
* Near record breaking arctic airmass returns for the weekend
* Tranquil weather day on Monday
* Closely watching a coastal system for Tuesday/Wednesday

Pattern Overview.
..
General agreement amongst the 00z model guidance. Overall pattern suggests an upper level trough over the Northeast with ridging building across the West. Have a high confidence in arctic airmass moving into the Northeast this weekend bringing near record breaking cold air to New England. Models then amplify the pattern over the West early next week resulting in a digging trough over the Great Lakes and into the Northeast. Run to run variability over the past few days has not improved confidence on the shortwaves moving through the flow. But both 00z deterministic and ensembles are hinting at a coastal storm for New England on Tuesday into Wednesday. This system could bring a late season snow as both the GEFS and EPS have high probs for accumulating snowfall across southern New England. Lots of uncertainty in this system still so will continue with a model blend for now.

Details...
Friday night into Saturday...High confidence
.
Arctic front will pass through southern New England overnight Friday into Saturday morning. Behind this front an anomolous arctic airmass 3 STD below normal will settle in for the weekend. As the front passes through, forecast guidance is showing a strong signal for snow squalls. This is indicated by very steep lapse rates, good moisture in the 0-2 km combined with convergence along the front. As these squalls pass through, vsbys could quickly reduce for anyone traveling Friday night. Low confidence on accumulation amounts.

As the arctic airmass continues to push into the region, expect ocean effect snow showers to develop into Saturday. Models are consistent in 850mb temps dropping to -24C. This will result in high temps in the teens and low 20s and lows back into the single digits. Trended towards to cooler guidance for Saturday, but feel the forecast is still a bit conservative especially with snow on the ground from the system on Friday. Will need to keep any eye on the possibility for wind chill headlines Friday night and again on Saturday night due to gusty winds and very cold airmass. In fact, there is the potential for a few of our climate sites to break their low and record low max temperatures.

Blustery conditions are expected for Saturday due to tight pressure gradient from approaching high from the west and departing low over the Maritimes. BUFKIT soundings show dry adiabatic conditions mixing well past 850mb. This could lead to gusts to 35-40 MPH. Wind headlines may be needed.

Sunday into Monday...High confidence.
Chilly airmass will remain over the region on Sunday but will begin to moderate temperatures into Monday. High pressure will build across New England leading to dry and less windy conditions.

Tuesday into Wednesday...Moderate confidence.
Models continue to advertise the potential for a coastal low for southern New England Tuesday into Wednesday. The GFS brings the low right over the benchmark where the EC is struggling with the phasing of both northern and southern streams. However, it develops a secondary low right over the benchmark. Regardless both GEFS and EPS are indicating above 50 percent probs of 6 inches or more across Southern New England. So confidence is increasing in accumulating snowfall, just a low confidence on timing, how much and where the axis will occur. Still a lot of details to be worked out so stay tune to the latest forecasts.
_______________________________________________________
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Mon Mar 13, 2017 11:29 am

Image

BLIZZARD WARNING
WINTER STORM WARNING
WINTER STORM WATCH

[b]...SIGNIFICANT SNOWFALL EXPECTED TUESDAY INTO WEDNESDAY...

.A strong low pressure system will track up the Eastern Seaboard and spread heavy snow into Southern New England, Vermont, Maine and New Hampshire Tuesday into early Wednesday. Snow will begin Tuesday morning in southern CT and spread northwards into western Maine by noon. Snow will become heavy Tuesday afternoon with snowfall rates of 1-4" per hour possible and blizzard conditions across CT, MA, & RI. The storm will come to an end overnight into early Wednesday morning.


[b]...WINTER STORM WARNING REMAINS IN EFFECT FROM 5 AM TUESDAY TO 2 AM EDT WEDNESDAY...

* LOCATIONS... Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont
* HAZARD TYPES...Heavy Snow, Very Fast Accumulations at times of 4+ inches per hour, limited visibility, drifting & blowing snow, impassible roadways in some areas.
* ACCUMULATIONS...Snow accumulation of 12 to 30 inches.
* TIMING...Snow begins between 5 and 7 am Tuesday morning. The snow will quickly become very heavy with 2 to 4 inch per hour snowfall rates possible at times into Tuesday afternoon.
* IMPACTS...Dangerous travel conditions due to near whiteout conditions at times and snow covered roads, especially Tuesday morning through early Tuesday afternoon. Strong winds may result in isolated power outages.
* WINDS...North 10 to 30 mph with gusts over 50 mph.
* VISIBILITIES...One quarter mile or less at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Winter Storm Warning means significant amounts of snow are expected. This will make travel very hazardous or impossible.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Thu Mar 30, 2017 9:00 am

Image

WINTER WEATHER ADVISORY
WINTER STORM WARNING
WINTER STORM WATCH

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Big Picture...

Longwave flow is nearly west-east with a slight trough over the Northeast USA. Shortwave scale flow shows northern and southern jet streams directing at least three and possibly four shortwaves through New England through the middle of next week. Approximate timing would bring one southern shortwave through on Saturday, a northern shortwave on Sunday, and another southern shortwave on Tuesday. Another shortwave crosses the nation on Wednesday but remains west of New England during the forecast period.

Differences in model mass fields with the GFS consistantly faster by 6 to 12 hours. The general pattern is similar but with a wide range of different details either side of that basic pattern. Pattern confidence is moderate through the weekend, diminishing to low by Tuesday-Wednesday.

Details...
Friday night and Saturday...

Midwest weather system redevelops along the Mid Atlantic coast early Friday night. The NAM was farthest north of the group Friday night...the ECMWF farthest north on Saturday. All positions are favorable for a slug of measureable precip as suggested by the precipitable water values which top out between 0.75 inches and 1.10 inches Friday night. The daily mean value for April 1 is about 0.5 inches and the 90 percent exceed value is 0.93, so these values are well above average.

Precip type will be quite varied but trending through sleet and freezing rain to rain through the period. Even southern areas could see some sleet at times Friday night. But those southern areas should change to rain, while northern areas start as snow and change to sleet/freezing rain Friday night...then to rain Saturday.

Winter Storm Watch continues north of the Mass Pike. Potential remains for 6 inches or more along the northern tier of MA with lesser amounts farther south. Additional concern is the water content of the snow, which is expected to be high. Looking at a sharp gradient in expected snow amounts between Northern MA and the Mass Pike corridor, in part due to the expected change to sleet/rain. This has limited our forecast confidence both in and adjacent to the watch area. So no changes in headlines planned at this time.

Low level southerly jet starts feeding the best moisture into our area starting Friday evening in CT and expanding east by midnight. We have 100 pct pops during this time frame. The moisture inflow diminishes on Saturday. Models show a band of strong low level winds around the coastal low as it passes Southern New England Saturday with speeds of 45 to 55 knots at 2000 feet above the South Coast and Islands. The ocean induced temperature inversion may keep the highest winds aloft, but potential for 30-35 knot gusts along the South Coast and Islands Saturday.

The low moves east of CT by afternoon and east of Nantucket by Saturday evening. Expect pcpn to diminish west to east during this time. It is possible the rain may change back to snow before ending.

Sunday and Monday...
High pressure builds in from the west bringing fair weather Sunday. Sufficient mixing during the afternoon from cold air aloft and daytime sunshine...gusty afternoon NNW winds. Temps aloft suggest max sfc temps in the mid 40s to lower 50s.

Continued dry weather and lighter winds Sunday night as the high builds overhead. Dew points in the 20s suggest min temps in the 20s and lower 30s.

Some increase in clouds Monday as the next weather system approaches, but otherwise a dry day under the high.

Tuesday...
Low pressure ejecting from the Southwest USA is projected to approach our area on Tuesday. This system bears some similarity to the Friday-Saturday system, including a weak cold air damming signal and a coastal redevelopment. This could be another coastal rain/inland mix situation, but currently expected temperatures support mostly rain.

Wednesday...
High pressure builds in with dry weather and near seasonable temperatures.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Tue Apr 11, 2017 7:20 am

Image

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1147 PM CDT Mon Apr 10 2017


Valid 111200Z - 121200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO NORTHEASTWARD TO SOUTHERN NEW ENGLAND...
Eastern Ohio northeastward to New England... Ahead of the advancing cold front in this region, southwesterly low-level flow will maintain 50s F dewpoints across the region as temperatures warm due to insolation. Mid-level lapse rates are relatively weak (only 5.5 to 6 deg C) across the region, which will limit the overall magnitude of surface based instability to between 500-1000 J/kg during the afternoon. Latest thinking is that scattered thunderstorms will develop amidst a unidirectional flow regime, with isolated instances of wind damage possible especially near any linear segments that can organize. This threat should primarily be diurnally driven, with the onset of boundary layer cooling reducing the severe threat shortly after dark.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Mon May 01, 2017 7:42 am

LARGE SEVERE WEATHER POTENTIAL

Image

ENHANCED SEVERE STORM RISK
MODERATE
SLIGHT



Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1233 AM CDT Mon May 01 2017

Valid 011200Z - 021200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THE EVENING ACROSS MUCH OF THE LOWER GREAT LAKES REGION...THE UPPER OHIO VALLEY AND THE CENTRAL APPALACHIANS INTO MID ATLANTIC COAST....
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENHANCED RISK AREA...AS FAR SOUTH AT THE SOUTHERN MID ATLANTIC COAST REGION...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK AREA...AS FAR SOUTH AS NORTHERN FLORIDA...

...SUMMARY...

Stong to Severe Thunderstorms are expected to develop and overspread much of the Lower Great Lakes region, the Upper Ohio Valley and Central Appalachians into the Mid Atlantic region today, accompanied by potentially damaging wind gusts and the risk for tornadoes.

...Synopsis...
Ridging within the mid-latitude westerlies, centered off both the Pacific and Atlantic coasts, may maintain amplitude during this period, but troughing in- between may broaden across much of the interior U.S., as a significant embedded short wave trough continues lifting northeastward out of the Plains/Mississippi Valley region. This latter feature will be accompanied by a deep lower/mid tropospheric cyclone which is forecast to track across and northeast of the Great Lakes region by 12Z Tuesday, with an associated cold front advancing into and across the Appalachians and much of the Atlantic Seaboard.

As one smaller scale impulse continues pivoting around the eastern and northeastern periphery of the mid-level cyclone, and another digs to its west and south, models suggest that the short wave trough will gradually transition from a negative to positive tilt centered over the Great Lakes by the end of the period. And the mid-level cold core will continue to considerably lag to the west of the warm sector of the occluding surface cyclone. However, substantial strengthening of deep layer wind fields appears likely today within the warm sector, across much of the Atlantic Seaboard by late afternoon. This is where forcing for ascent is expected to support considerable thunderstorm development, which will probably be accompanied by potentially damaging wind gusts, and perhaps a few tornadoes.

...Eastern states...
Models indicate strengthening of warm sector 850-500 mb wind fields to 40-70+ kt during the day today, particularly across the lower Great Lakes region, the upper Ohio Valley and the central Appalachians into the northern Mid Atlantic Coast region. This should prove more than favorable for organized severe thunderstorm development, given at least weak boundary layer destabilization, and surface dew points in the 60s probably will contribute to this with daytime heating, despite relatively warm and initially capping mid-level layers. Beneath increasingly difluent flow aloft, frontal and orographic forcing for ascent are expected to aid initiation of thunderstorms near/east of Lake Erie, southward along the western slopes of central into southern Appalachians by 18-21Z. This activity seems likely to eventually consolidate and grow upscale into an organizing squall line as it crosses the Allegheny mountains and plateau, and to the lee of the Blue Ridge, by early evening. As it does, it probably will be accompanied by increasing potential for damaging surface gusts, given the strength of the ambient wind fields, with damaging straight line winds becoming the predominant severe threat. However, supercell structures, within and perhaps ahead of the line as it evolves, may be accompanied by a risk for tornadoes, some of which may be strong.

Strong/severe storms may reach the Champlain/Hudson Valleys and Mid-Atlantic coastal areas by this evening, before weakening within a more stable environment.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Wed May 31, 2017 7:16 am

HEADS UP!
Severe Thunderstorms are likely today, across NY State and much of Southern-Western-Central New England, with large hail, very strong winds, and a slight risk for tornadic activity. Overcast skies will help to keep the atmosphere stable, but clearing is expected to progress from West to East later this morning. Hopefully, the clouds will remain over our region and limit daytime heating, but the more sunlight we get, the more gas there is for the storms to get worse.


Image
Image

SUMMARY...
A few severe storms capable of strong, damaging winds and large hail will be possible from parts of New England southward to the Mid-Atlantic. Another area of strong/severe storms is expected from the central High Plains to the Ozarks. Isolated strong to marginally severe storms will also be possible across southwestern Texas and the northern Rockies.

...Synopsis...
Broad cyclonic mid-level flow will persist across much of the eastern U.S. today, with a corridor of enhanced mid-level flow (around 50-60 kt) from the Ohio Valley east/northeastward to New England. Within this flow regime, a shortwave trough (currently observed near the mid Missouri Valley in water-vapor imagery) will approach the Northeast during the afternoon. Farther west, a ridge will build over portions of the northern High Plains, resulting in northwesterly flow aloft over the central Plains and lower Missouri Valley.

...Northeast to the Mid-Atlantic...
Similar to the previous day, the cyclonic-flow regime situated over much of the eastern U.S. will place vigorous mid-level flow over much of the region. With broad mid-level ascent overspreading portions of the Mid-Atlantic and New England, a surface trough will gradually organize from Virginia northward to the Hudson Valley during the day. Along and to the east of this trough, southerly surface flow will spread dew points in the upper 50s/lower 60s northward across parts of the Mid-Atlantic and southern New England, resulting in an axis of enhanced low-level theta-e. Additionally, guidance suggests mid-level drying will support enough cloud breaks for adequate boundary-layer heating during the day, especially considering the cold mid-level temperatures present. In turn, MLCAPE values around 1000-1500 J/kg will likely materialize from southeastern Pennsylvania north/northeastward to southern New England. Convection will gradually organize near the trough through the afternoon, and relatively straight hodographs suggest splitting cells will generally evolve into small bowing segments capable of damaging winds. Additionally, initially discrete cells will likely be efficient hail producers, bolstered by effective shear near 40-50 kt and 500-mb temperatures near -20 C.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Wed May 31, 2017 2:55 pm

Image

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 300
NWS Storm Prediction Center
Norman OK
125 PM EDT Wed May 31 2017


The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of
Western Connecticut
Western and Central Massachusetts
Southwest Maine New Hampshire
Eastern New York
Vermont

* Effective this Wednesday afternoon and evening from 125 PM until 900 PM EDT.
* Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Scattered thunderstorms are forecast to develop over central/eastern New York and spread eastward across the watch area this afternoon and early evening. The strongest cells will pose a risk of hail and gusty/damaging wind gusts. The severe thunderstorm watch area is approximately along and 75 statute miles east and west of a line from 35 miles northeast of Newport VT to 45 miles east of Monticello NY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...

A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
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Re: NWS Radar & Severe Weather Statements

Postby Brother Al » Sun Jun 18, 2017 8:51 pm

MONDAY JUNE 19, SEVERE WEATHER FORECAST MAPImage
NWS Storm Prediction Center
Norman OK
1220 PM CDT Sun Jun 18 2017

Valid 191200Z - 201200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC AND SOUTHWEST NEW ENGLAND...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OUTSIDE OF THE ENHANCED RISK AREA FROM WESTERN NORTH CAROLINA TO NEW ENGLAND...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OUTSIDE OF THE SLIGHT RISK AREA FROM THE LOWER MISSISSIPPI VALLEY INTO THE CENTRAL AND NORTHERN APPALACHIANS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across portions of the Northeast into the Mid-Atlantic states Monday afternoon into the early evening. Damaging wind gusts will be the primary severe hazard but large hail is also possible.

...Mid-Atlantic/[b]NEW ENGLAND
/Western North Carolina...
An upper-level trough will move across the Great Lakes and Ohio Valley on Monday as southwesterly mid-level flow remains over the Northeast. At the surface, a cold front will advance eastward across the lower Great Lakes and Ohio Valley. Ahead of this front, surface dewpoints in the mid to upper 60s F should result in a corridor of moderate instability from the Carolinas north-northeastward into the Mid-Atlantic. Thunderstorm development should take place along the front during the morning with a gradual expansion of convective coverage taking place in the afternoon. Several line segments may organize along the front moving to the coast of the Mid-Atlantic by early evening.

At mid-levels, a 60 to 75 kt mid-level jet will move northeastward across the central Appalachians on Monday. Lift and deep-layer shear is forecast to be maximized on the southeastern edge of the mid-level jet where the greatest severe threat is expected Monday afternoon. NAM forecast soundings at 21Z from eastern Virginia to southeastern New York show MLCAPE from 1200 to 1800 J/kg with south-southwest flow at the surface and very gradually veering winds with height in the low to mid-levels. This wind profile with 0-6 km shear of 30 to 40 kt will support severe multicell line segments capable of producing damaging wind gusts. The faster moving short bowing line segments may produce longer swaths of wind damage mainly from Maryland north-northeastward into southwestern New England, where the enhanced risk has been maintained.

The potential for damaging wind gusts should be more isolated from central Virginia into western North Carolina where large-scale ascent is forecast to be considerably less than in areas to the north. Isolated large hail could also occur with the stronger updrafts along the front.

A Flash Flood Watch has been issued for most of eastern New York and
western New England, except for the western Adirondacks, from Monday
afternoon through much of Monday night...[/b]

...Severe thunderstorms and flash flooding possible for some areas Monday...

As of 730 PM EDT, clusters of showers/thunderstorms originating from west/central NY are migrating east/northeast across the Western Adirondacks, especially near and north of NY Rte 28. Additional isolated showers have redeveloped across portions of the mid Hudson Valley, Litchfield Hills CT, Southern VT, and Eastern Catskills.

The convective potential will continue to increase over the next several hours for the remainder of the southwest Adirondacks and west/central Mohawk Valley, as thunderstorms currently developing across central/western NYS migrate toward these areas. There is the potential that storms currently advancing east from central/south central NYS continue to translate into these areas between roughly 8-11 PM this evening, with damaging wind potential due to embedded bowing segments, hence the Storm Prediction Center`s area of Slight Risk for severe. These bands/lines will be becoming farther removed from upper level support, so main maintenance mechanism after sunset will be from momentum remaining from leading edge of cold pools generated from current storms, which may still support some potential for strong wind gusts extending into portions of E.NY, W.CT, VT, and W.MA, roughly between 11 PM and 2 AM. This area is under a marginal risk for severe thunderstorms, again mainly for the potential for isolated damaging wind gusts.

Humid conditions continue through Monday night. There is an increased risk for severe thunderstorms, as well as flash flooding for some during Monday afternoon and evening. A cold front over Southern New England moves offshore Tuesday. Weak high pressure then builds over the region Wednesday and Thursday with seasonable temperatures and lower humidity. Warmer temperatures return late in the week as the high moves off to the east and another cold front approaches from the west.

SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
*/ Highlights...
* Localized Flash Flooding along with the potential for severe
thunderstorms exists across western and central MA and
portions of northern CT tomorrow afternoon and night


*/ Discussion...
Strong upper level jet and attendant mid lvl shortwave pivot into NY/PA through the morning tomorrow. This allows the equatorward entrance region of the mean upper jet to line up such that best venting is focused on E NY/PA/NJ into western SNE by mid-late afternoon. Lapse rates in this airmass are not the best, mainly 5.5-6.0C/km given this is not an EML type situation. If anything, the high PWATS promote HPE type storm development. The cold front remains W through 00Z, shifting into New England only by about 06Z, however noting enough slackening in mass fields to suggest modest pre-frontal trof as a focus for convection beginning across E NY/PA/NJ first, then shifting E as remnant low stratus dissipates mid day-afternoon. Given these facts, best chance for severe will remain within area enhanced area highlighted by both SWODY3 (yesterday) and SWODY2 (today), mainly across E NY into portions of W New England.

Timing...
Prefrontal trough development, combined with a consensus look at available mesoscale guidance, suggest that best activity falls across NY, W.MA, CT, VT, NH, ME between 2PM and 8PM from West to East. While linear structure to the convection is expected moving E with mid level flow, individual cells/line will actually be shifting SW to NE with time, slowing the overall progression, hence the slow timing. Further East, late evening and overnight timing expected for Eastern MA/RI, as activity may not start until near or after sunset for those furthest E. Storms could even be dissipating with time due to loss of diurnal support. Will continue to highlight a slight risk for severe however, as upper level CAPE profiles are maintained well into the overnight hours and shear values change little.

Severe threat...
0-6 km shear values peak during the afternoon within a somewhat linear wind profile, 30-40 kt. This is within an airmass holding 1500-2000j/kg sfc based and ML CAPE values. Noting that hodographs within this shear suggest multicell clusters potential forming a more organized lines of convection which would enhance the risk for damaging winds. This will be the primary severe threat. 400-500j/kg of CAPE within the hail growth region support some small hail as well. Noting EHI values 1-3 and low LCLs, which also suggest a low risk for Tornadic Activity as well, which will need to be watched especially where enhanced valley motions are able to shift the low lvl flow more SE enhancing the low lvl shear.

Flash Flooding Threat...
As mentioned before an east propagating line of storms will see individual cell structures actually move SW-NE, this suggests training within an airmass primed for HPE storms. CAPE profiles are relatively skinny given the modest lapse rates. PWATS exceed 2 inches widespread and warm cloud layers 10-13kft. This could easily lead to rainfall rates near or exceeding 2 inches per hour especially across E.NY, W.MA, CT, & VT where highest theta-e plume is noted. This plume has shifted slightly E with latest data updated, and given that at least elevated convection will hold later into the evening/overnight will be expanding the Flash Flood Watch to include Tolland CO in CT as well as Worcester and NW Middlesex COs in MA.

Overall, will highlight strongest threat for severe weather and flash flooding late day tomorrow into the early hours of the overnight tomorrow night. The severe threat will diminish as the storms move east into E MA and RI late evening and overnight, but these will still need to be watched even as some storms continue.
_______________________________________________________
"Corp America Got Bailed Out, WE Got Sold Out"
--------------------------------------------------
May the Tin Indian and JZD Rest in Peace
Prius, Proof that people will buy Anything, (Baaaa Baaa)
All the Answers to our Problems can be found in the Boneyard!
God Bless America & those who serve & have served our Country!
User avatar
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