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000 
FXUS61 KBOX 262138
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
438 PM EST Sun Feb 26 2017

.SYNOPSIS...
High pressure centered south of New England brings dry weather
through Monday. Milder air moves back into our region Monday,
then lingers through much of this week. A couple of weather 
systems will bring periods of wet weather Tuesday into Wednesday
night. Colder air returns late this week into next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...

Into this evening /4 pm update/...

Winds should taper as cloud cover over W portions of S New
England should dissipate. Given the dry conditions across the 
region with dewpoints bottoming out in the mid- to low-teens 
during max heating of the day, expect temperature to drop rather
quickly with sunset. Much of the region well down into the 30s 
towards 7p with upper 20s across the N/W high terrain of MA. As 
to winds, gusts of around 20 to 25 mph continuing, strongest 
over the high terrain and along the coast. That'll yield wind 
chills that are roughly around 10 degrees lower than the 
ambient. 

Tonight...

No issues anticipated. High pressure emerging off the Mid-
Atlantic along the NW-periphery of which warmer H925 air is
pushed northward allowing for boundary layer decoupling over 
the interior. Thinking light winds with mostly clear conditions 
indicating a radiational cooling setup. A couple of things to 
consider: 1) Low surface dew points during max heating of the 
day with blustery W winds that has more than likely led to areas
of dry soils, 2) surface winds while light are becoming 
southerly overnight, and 3) significant snow cover over the high
terrain of far N/W MA. All this in mind, leaning towards colder
guidance with lows generally around the mid 20s, pockets of low
20s in notorious spots away from urban centers, with upper 
teens over the N/W high terrain of MA. 

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...

Monday...

Continued quiet weather. Roughly 1030+ high pressure prevailing
off the Mid-Atlantic, S of New England, slowly moving E. 
Persistent S/SW flow as forecast models suggest deep boundary 
layer mixing up to H8 given the milder airmass aloft and 
expected mostly clear conditions with some increasing mid- to 
high-cloud late from the SW. Within the modest SW to NE gradient
flow, daytime mixing will lead to the mix- down of faster 
momentum and drier air to the surface. Another dry day on tap 
with SW wind gusts up around 20 to 25 mph, stronger over the 
S/SE coast with gusts up to 30 mph possible. Leaned with the 
warmest of temperature guidance considering: 1) deep boundary 
layer mixing of warming air aloft, 2) abundant sunshine, and 
lastly 3) bare ground over much of S New England. Highs around 
the low to mid 50s. Can not rule out low-lying locations of the 
Merrimack River Valley to nudge near 60 degrees. 

Monday night...

Perhaps the chance of a spotty shower by morning. The SW-NE 
gradient tightening out ahead of low pressure emerging along the
lee of the Rockies, some initial mid-level vortmax energy
emerges from the H5 trough situated across the W CONUS.
Invocation of a lifting warm front along which we see initial 
over-running moisture with higher theta-E values creeping into 
our region during the morning lending to moistening of the low- 
to mid- level column, there is some measure of weak lift that 
may result in a spot shower. Aside, at a minimum, continued 
increasing and thickening clouds with continued S flow. Given 
the blanket of clouds, leaning somewhere between the mean to 
warmer end of temperature guidance with lows fluttering around 
the mid- to upper-30s. Coolest spot in N/W MA. Thinking slight 
chance PoPs as a consensus of model forecast guidance has us 
mostly dry with only higher theta-E creeping in out of the SW by
morning, and lift is rather weak, mostly isentropic. Focus of 
PoPs over SE New England. 

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Highlights...

* Above average temperatures for most of this week
* Widespread showers possible Tuesday through late Wednesday
  night
* More seasonable conditions return Friday into Saturday

Overview...

26/12z guidance continues to show rather good agreement on the
overall pattern through Friday. That said, there are the 
typical discrepancies in the timing and amplitude of shorter 
wavelength features toward the end of this week. Since these 
sorts of details are usually less predictable at this time 
range, still prefer a consensus approach.

Details...

Tuesday...High confidence.

High pressure to our south will move slowly offshore. This will
result in an increasing southwest flow, which means good
overruning, with increasing clouds, and eventually rising 
temperatures. While not close to the record warmth late last 
week, still expecting temperatures well above normal.

The greatest risk for precipitation will be toward the south
coast, where moisture should be deeper. Depending upon the
timing, it's possible for some wet snowflakes to fall during the
morning along and north of Route 2. Low confidence in that
happening.

Presence of a strong low level jet Tuesday night should lead to
either steady or slowly rising temperatures overnight.

Wednesday into Thursday... Moderate confidence. 

Main weather producer will occur Wednesday into Thursday. Still
some  uncertainty on the timing and location of the surface 
low. 

Our region should remain in the warm sector of a low pressure
moving through the Great Lakes. Strong southwest winds aloft
are likely to bring an unseasonable amount of moisture our way.
This expecting plenty of clouds. Rainfall amounts however are
generally expected to be less than one half inch for most of our
region. 

Convective instability will be the wildcard. Most convective
indices are rather marginal. However, if we could get some low
level instability to go along with the wind shear, then a few
thunderstorms may develop. This has been consistent, weak signal
the past couple of days. By no means is this a lock, but will
keep the mention of isolated thunderstorms in the forecast. 

Still have high confidence that at least some precipitation 
will fall, and temperatures will be above average Wednesday 
into Wednesday night. 

Cold front will sweep through early Thursday morning, resulting
in drying conditions with falling temperatures falling through 
the day. Strong cold air advection likely to mean gusty west to 
northwest winds. 

Friday and beyond... Moderate confidence. 

26/12Z GFS remains the model with the strongest hint of a
clipper-like low pressure passing by to our south Friday 
morning. The other models are neither as aggressive, nor as
humid. Favored the drier consensus solution for now. This will
be something to watch over the course of this week. 

High pressure remains to our south next weekend. After a period
of more seasonable temperatures Friday and Saturday, it appears
we get back into more of a warmup next Sunday.

Good mixing and cold air over the ocean may result in ocean 
effect snow showers next weekend, before another clipper system
possibly approaches towards late Sunday.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

Short Term /through Monday Night/...

Tonight... 

VFR. SKC. Initially blustery with gusts around 20 to 25 kts,
winds become light out the W while gradually turning out of 
the S. 

Monday...

VFR. Increasing SCT-BKN mid to high level cigs late. S/SW winds  
around 240 becoming breezy through the day with 20-25 kt gusts, 
strongest over the high terrain and along the coast, dissipating 
into the evening hours. 

Monday night...

VFR. Cigs becoming BKN-OVC, lowering to low-end VFR with a risk 
of MVFR over S-coastal terminals. Light S flow around 5-10 kt. 


KBOS TAF...High confidence in TAF. 

KBDL TAF...High confidence in TAF. 

Outlook /Tuesday through Friday/...

Tuesday into Wednesday...Moderate confidence. Periods of -RA
through the period will result in MVFR/IFR conditions. Cannot 
rule out LIFR in fog during the overnight hours. 

Thursday...Moderate confidence. VFR conditions from west to 
east during the morning. Blustery westerly winds are possible.

Friday...Moderate confidence. Mainly VFR, with MVFR possible
toward the south coast, including the Cape and islands.

&&

.MARINE...
Forecaster Confidence Levels...

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

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

Breezy W flow turns out of the S overnight. Overall a prolonged
period of continued gusts around 20 to 25 kts with lulls during
the overnight hours result in the continuation of small craft 
advisories as seas are slow to dissipate, remaining at or above
5 feet on the E outer waters and both inner and outer S waters.
Small craft advisory conditions persist into Monday evening, 
concluding thereafter. 

Outlook /Tuesday through Friday/...

Tuesday...Moderate confidence. Improving conditions across the 
waters as high pressure passes southward. Warm frontal passage late 
Tuesday could drop vsbys in rain and fog. 

Wednesday into Thursday...Moderate confidence.  Approaching system 
from the west will push a cold front through on Thursday, increasing 
both seas and winds during this period. Heavy rain and a few 
thunderstorms are possible, lowering vsbys. There is the 
potential for southerly gales across the waters Wed night, and  
northwesterly gales on Thursday behind a cold front.

Friday...Moderate confidence. Gusty west winds continue. Small
Craft Advisories likely will be needed for some of the coastal
waters.

&&

.FIRE WEATHER...
Dry and blustery conditions will persist on Monday pushing
minimum relative humidity values at or below 30 percent for a 
good portion of interior Southern New England as southwesterly 
flow gusts up around 25 mph. 

Considering in the last 24 to 36 hours much of Western and
Central MA and CT saw around 0.50-0.75" of liquid, with around 
0.10-0.25" to the east, there's some concern of potential fire 
weather conditions over Northeast CT, RI and Eastern MA as 
temperatures warm into the mid to upper 50s. 

&&

.HYDROLOGY...
Rising water levels, partly from rain overnight but also from
snowmelt in Northern New England. A couple of rivers in the CT
River Valley rose above alert stage during the night, but 
crested below warning stage. Others crested below alert stage. 

There is still plenty of water moving downriver from the
snowpack. We will need to monitor water levels across southern 
New England for a while this week.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 1 AM EST Monday for ANZ231>235-237-
     251.
     Small Craft Advisory until 7 PM EST this evening for ANZ230-
     236.
     Small Craft Advisory until 1 AM EST Tuesday for ANZ250-254.
     Small Craft Advisory until 10 PM EST Monday for ANZ255-256.

&&

$$
SYNOPSIS...Belk/Sipprell
NEAR TERM...Sipprell
SHORT TERM...Sipprell

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