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Area forecast discussion
National Weather Service Taunton Massachusetts
929 am EST Tue Feb 21 2017

high pressure centered over New England today moves offshore
tonight and Wednesday. This brings US dry weather and a trend
toward milder temperatures through the week. A weak cold front
dissipates as it crosses New England late tonight. A series of
low pressure systems move through the Great Lakes Wednesday
through Saturday maintaining unseasonably mild temperatures in
New England, with near record warmth possible Thursday. A
strong cold front will cross the region Saturday, likely
bringing some rain, followed by blustery and more seasonable
conditions Sunday and Monday.


Near term /until 6 PM this evening/...
930 am update...
high pres surface and aloft builds across new eng today. Leading
edge of overrunning high clouds will spill into the region
resulting in increasing cloud cover from west to east,
otherwise pt-mosunny skies. Highs will reach the low to mid 40s
across much of the region with some upper 40s possible in the
coastal plain. Seabreezes will likely develop along the coast
where temps will cool a bit this afternoon.


Short term /6 PM this evening through 6 PM Wednesday/...

High pressure shifts offshore. Airflow is light during the
evening, which should allow temps to cool initially. South-
southwest flow then increases a little overnight. Sky cover
mostly thin in the evening with high clouds, but this thickens
through the night. Because of both factors, we expect
temperatures to cool in the evening, but then rise slowly after

Dying cold front is being pushed along by a 105 knot upper jet
which is also diminishing. Sufficient moisture for clouds
overnight. Possible brief period of lift between midnight and
dawn. This doesn't inspire great confidence of pcpn, but enough
to maintain low-end chance pops.

If there is pcpn, what type will it be. Surface temps will be
either side of freezing in the interior, and in the mid 30s
closer to the coast. So there is a chance that showers may
produce scattered icy spots in the interior. With the scattered
distribution of the showers and their possibly drying up as they
move east, expect any icy spots to be limited in coverage. But
drivers will need to exercise caution.


High pressure lingers offshore with a south-southwest flow of
air into srn New England. Lingering clouds during the morning
should thin and provide at least partly sunny skies. Temps at
1000 mb and 950 mb support Max sfc temps near 50. Temps at 925
mb support Max sfc temps in the upper 50s. Expect Max sfc temps
in the 50s, possibly close to 60 if we get sufficient solar


Long term /Wednesday night through Monday/...

* record warmth possible Thursday
* linger cold front on Friday make keeps temps cooler
* mild with widespread showers likely sometime Sat/Sat night
* blustery and cooler sun/Mon

Pattern overview...

00z guidance is in general agreement synoptically, still have some
mesoscale features to resolve. Overall, mean ridge to start the
forecast period for southern New England as digging trough develops
of the western Continental U.S.. this trough will eject across the plain and
eventually move towards the northeast by Saturday/Sunday. Before
then, a weak northern stream wave will move through late Thursday
into Friday which could sag a weak cold front through the region.
After potent trough moves through the area pattern appears to turn
more zonal resulting in several shortwaves moving through the flow
for next week. High confidence in above average temperatures for
Thursday and Saturday as well as precipitation on Saturday into
Saturday night.


Wednesday night into Thursday...

High pressure offshore on Wednesday night resulting in the
return of southerly flow. Guidance keeps most of the day dry on
Thursday, however have noticed and increase in low level
moisture. BUFKIT soundings do show a saturated profile in the
low levels with dry air aloft, so cannot rule out low level
clouds and/or drizzle for the area. Best location will be across
the South Coast.

These low clouds may limit the amount of heating during the day. But
with the potential mixing up to 950mb could still see low to mid
60s. Right now trended towards the low 60s because of low level
moisture. This will be close to records for a few sites in southern
New England.

Cannot rule out the potential for some wind gusts on Thursday as 925
mb low level jet increases to 30-40 kts. If we mix higher than 950 mb then we
could see gusts close to 25-30 miles per hour.


Again a good check of Friday appears to be dry, but low level
moisture continues to increase which could keep the drizzle
potential for the area.

Guidance continues to show a back door cold front late Thursday into
Friday which could limit high temperatures. Highest confidence in
across northeast Massachusetts but the front could sag a bit farther southward.
Large temperatures spread is possible and high confidence in bust
potential, will have a better handle with hi-res guidance.

A warm front will push through the region late Friday keeping
temperatures overnight well above average. Could see a few showers
associated with this warm front.


Potent shortwave will move through the flow and approach southern
New England on Saturday. This wave will drag a cold front across the
region ending the chances for above average temperatures.

Ahead of the front, anomalous southerly flow with low level jet increasing
to 35-45 kts as 925 mb temps warm to 12c. This will result in above
average temperatures for the region as well as gusty winds. Precipitable water
values also increase near 3 Standard above normal as southern stream
moisture is fed into the system. Will have to watch for secondary
surface low that may develop along the front, which could indicate
heavy rain for the region. Low confidence on thunder potential as ec
ensemble mean indicates some instability.

Frontal passage will be quick as temperatures plummet behind the front. Could
see some wet flakes on the backside depending on how much moisture
is left as front moves through.

Sunday into Tuesday...

Chilly and blustery northwest flow will take over the region by Sunday into
Monday. Temperatures difference between Saturday and Sunday could be
close to 20f. Wind gusts could also increase close to 30 miles per hour as the
region mixes well above 850mb.

A weak wave appears to move through the flow on Monday into Tuesday,
which could result in some rain/snow showers for the region. Low
confidence on timing, but it is moving quickly and bringing in
another round of cold air.


Aviation /14z Tuesday through Saturday/...
forecaster confidence levels...

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short term /through Wednesday/...

Today...high confidence.
VFR with some high clouds. Light wind, with coastal seabreezes

Tonight...moderate confidence.
VFR much of the night. Possible MVFR cigs/vsbys in showers
especially over northern CT and western Massachusetts. Depending on surface
temperatures, there may be the potential for patchy freezing
rain in interior Massachusetts.

Wednesday... moderate confidence.
Mainly VFR but increasing low level moisture may keep cigs MVFR
during the first half of the day.

Kbos taf...high confidence in taf. Seabreeze expected to develop
around 18z.

Kbdl taf...high confidence in taf.

Outlook /Wednesday night through Saturday/...

Thursday...moderate confidence. Mainly VFR but low clouds could
keep conditions MVFR.

Friday...low confidence. Potential for easterly flow and MVFR cigs
if backdoor front slips to the south. However, VFR with SW winds if
front remains to the north.

Saturday...moderate confidence. Potential for widespread MVFR/IFR
conditions with rain overspreading the region.


forecaster confidence levels...

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short term /through Wednesday/... high confidence.


High pressure builds over the waters. This will bring diminishing
winds and seas. All lingering small craft advisories will be


High pressure moves off to the east, bringing increasing wind
from the south-southwest. Winds and seas remain below small
craft thresholds. A diminishing cold front may bring scattered
showers to the waters late at night.


Any showers will dissipate. Winds will increase from the
southwest, but should remain at 20 knots or less. Seas will be
3 feet or less.

Outlook /Wednesday night through Saturday/...

Wednesday night into Thursday...high confidence. Mainly SW flow with
gusts to 20 kt. A few gusts to 25 kt possible Thu afternoon.

Friday...low confidence. Winds will depend on location of a backdoor
front. Easterly flow if the front moves to the south, but continued
SW flow with gusts to 20 kts possible if front remains to the north.

Saturday...moderate confidence. Increasing southerly flow with Small Craft Advisory
gusts likely. Waves will also increase in response. Vsbys reduced in
developing rain and fog.


record highs for Thu Feb 23



Box watches/warnings/advisories...
Rhode Island...none.


near term...wtb/kjc
short term...wtb

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