Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 271540
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
1040 AM EST Sun Nov 27 2016

.SYNOPSIS...
High pressure slowly builds into the region through Monday with
generally dry weather, seasonable highs, and cool lows. A warm
front will bring widespread rain to the region Tuesday into
Tuesday evening, then more rain is likely late Wednesday into
Thursday as low pressure moves into New England. Cooler and drier
weather will return for Friday and Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

Satellite shows a band of mid-level clouds, bases about 10
thousand feet, across Western MA and CT. An area of lower clouds,
bases around 3500 feet, has moved into NW MA. Expect these clouds
to remain over the region this afternoon. Lingering cloud level
moisture and daytime mixing should bring a period of diurnal
clouds during the afternoon.

Mixing to 900...observed CHH temp -1.5 and ALB -3.5C...or 925
mb...observed CHH temp -0.5C and ALB -2.0C...would generate max
sfc temps in the 40s.

Per satellite, ocean effect clouds are in place across the Outer
Cape. Provincetown winds are near 20 knots. Air-water difference
of 13-15C and NW winds should keep the clouds there through the
afternoon. Radar detecting some light echoes, so a sprinkle
possible...but mostly dry.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Tonight...
Diurnally driven SC should dissipate with drier air attendant to
high pres building over from the NW. This high also allows pres
gradient to rapidly slacken through the evening. Therefore,
expecting radiational cooling across much of the region. Leaned on
the coldest of guidance as temps at the top of the inversion are
as low as -6C. This was actually featured in the MET/CMC, noting
several locations in the low-mid 20s, except the heat islands
which may only dip just below freezing.

Tomorrow...
Another pleasant day on tap thanks to dry subsidence within the
slowly exiting high pres and plenty of sunshine. Still, the
subsidence inversion is expected to suppress the BL somewhat in
comparison to previous days even as H92 temps warm to above 0C
(near +2C to be exact). This will keep temps once again mainly in
the mid 40s for highs in spite of the more sunny conditions. The
colder start to the day won`t help much either.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Highlights...

* Dry and cool Monday
* Rain Tue, especially afternoon and evening. Low risk of brief
  icing at the onset Tue morning N/NW MA
* Dry early Wed, then more rain late Wed into Thu
* Mainly dry and blustery Fri/Sat

Overview...
Model guidance is in good agreement on the large scale pattern in
the extended period. High amplitude longwave trof moves into the
central CONUS through the mid week with closed low moving into the
Gt Lakes. Series of shortwaves and attending sfc waves within a
deepening moisture plume will bring multiple periods of beneficial
rain during the Tue to Thu timeframe. Then looking ahead to the end
of the week and next weekend, a split flow pattern evolves with New
Eng under the influence of a dominant northern stream trof which
will bring cooler and drier conditions.

Monday night...
High pres over New Eng moves to the east. While clouds will increase
overnight, it appears dry air will hang on through the night with
leading edge of precip remaining to the west.

Tuesday...
Warm front approaches from the south and west with increasing
isentropic lift developing from west to east. Low level forcing for
ascent will be enhanced by a 50+ kt low level jet which also
transports high PWAT plume into New Eng. Leading edge of the rain
will likely move into western zones during the morning and there may
be pockets of freezing rain across interior northern and western MA
if the precip comes in early enough when sfc temps are at or below
freezing. Timing of rainfall will be critical to freezing rain
potential. Bulk of rainfall will occur during the afternoon and into
the evening across eastern New Eng assocd with the axis of the low
level jet, then rain tapers off as dry slot moves in with weak
ridging as sfc wave exits. Rainfall of 0.50-1.00 inch expected
through Tue evening. Temps may hold in the upper 30s and lower 40s
north of the pike but could spike into the 50s by late afternoon to
the south, especially across RI and SE MA if warm front lifts north
into SNE. How far north warm front gets is still uncertain so low
confidence temp forecast.

Wednesday and Thursday...
Next batch of rain arrives by late Wed/Wed evening lasting into Thu
as another warm front and sfc wave tracks into New Eng. Additional
rainfall of 0.50-1.50 inches possible so total rainfall from Tue
through Thu is expected to be 1.00-2.50 inches. Timing of how long
the rain lingers into Thu is uncertain and could see improving
conditions later Thu but low confidence. Higher confidence of a dry
period into Wed morning with some sunshine possible as SNE will be
in between systems with weak ridging. Low confidence temp forecast
Wed will depend on position of warm front and how quickly clouds and
rain return.

Friday and Saturday...
Looks mainly dry and blustery as low pres moves into the Maritimes
with W/NW flow. However, mid level trof will be over the NE with a
few shortwaves rotating through so can`t rule out a few rain/snow
showers. Temps will cool back to near normal levels.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels.

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

Short Term /through Monday/... High Confidence

This afternoon... VFR, except MVFR cigs over Outer Cape Cod due to
ocean effect clouds. Winds out of the NW, with a few gusts around
20-25 kt at coastal terminals.

Tonight and Tomorrow...
VFR. Winds shift to the W-NW rather than truly NW, but should
remain mostly around 10 kt or less.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday night...High confidence. VFR.

Tuesday...High confidence in trends. Conditions lowering to MVFR/IFR
as widespread rain moves into the region with patchy fog. Rain exits
Tue night with improving conditions to VFR overnight.

Wednesday into Thursday...High confidence in trends, low confidence
in timing. VFR to start then MVFR/IFR conditions return by late Wed
into Thu as more rain moves into the region.

&&

.MARINE...
Forecaster Confidence Levels.

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

Short Term /through Monday/...High confidence.

This afternoon and tonight... NW wind gusts will continue to gust
to around 25 kt through the day and early evening hours especially
along the outer waters. The lingering swell form deepened low pres
to the E combined with this winds will yield a seas 5-7 ft along
the outer waters as well. Small craft advisories linger as
forecast.

Tomorrow...
Only the outer E waters will remain under Small Craft Advisories
during the early daylight hours as swells subside, but even these
two should drop below the 5 ft threshold by the afternoon, such
that by late in the day, boating wx will be quiet.

Outlook /Monday Night through Thursday/...

Monday night...High confidence. Light winds and seas as high pres
gradually shifts east of the waters.

Tuesday...Moderate confidence. Increasing SE winds with a period of
SCA southerly gusts late Tue/Tue evening as low level jet moves
through. Low risk of brief marginal gale force winds Tue evening.
Vsbys lowering in developing rain and fog.

Wednesday and Thursday...Low confidence wind forecast will depend on
track of sfc wave into New Eng and position of warm front. Light
N/NE winds Wed will likely shift to SE and increase late Wed/Wed
night. Potential for strong SW winds late Wed night or early Thu
over south coastal waters if low tracks across SNE. Winds should
eventually shift to W later Thu as low pres moves to the north.
Another period of reduced vsbys in rain and fog late Wed into Thu.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EST this evening for
     ANZ232>234.
     Small Craft Advisory until 5 AM EST Monday for ANZ231-251-256.
     Small Craft Advisory until 1 AM EST Monday for ANZ235-237.
     Small Craft Advisory until 1 PM EST Monday for ANZ250-254-255.

&&

$$
SYNOPSIS...KJC/Doody
NEAR TERM...WTB/KJC/Doody
SHORT TERM...Doody
LONG TERM...KJC
AVIATION...KJC/Doody
MARINE...KJC/Doody



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