485 
FXUS61 KBOX 152057
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
357 PM EST Wed Feb 15 2023

.SYNOPSIS...
A warm sector airmass remains over the region tonight into Thursday, 
ahead of an approaching frontal boundary, yielding near record 
warmth. Rain, fog, and gusty southwest winds are expected Thursday 
night and early Friday, then falling temperatures and strong north 
to northeast winds by Friday afternoon. A brief cooldown to more 
seasonable levels Friday night into Saturday, with chilly weather. 
Warmer Sunday into Tuesday with a chance of showers Monday and 
Tuesday with another frontal system.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
330 PM update...

Tonight...

Short wave trough exiting the Great Lakes and resulting in 
downstream low pressure over Quebec, yielding a tight southwest 
pressure gradient across MA/RI/CT, with gusts up to 35 mph. Low 
level jet over SNE providing impressive thermal advection, with 
surface temps at 330 pm in the upper 50s to lower 60s! True warm 
sector air (+14C at 925 mb) currently over southwest PA into WVA 
arrives here around 06z across southeast MA. The departing short 
wave drops a frontal boundary into the region later tonight, 
shifting winds to the west, but very little cooling. Therefore, a 
very mild night by mid Feb standards, with lows only in the 40s! 
Keep in mind, the normal high temp for this time of year is 35-40. 
Decreasing low level moisture this evening and drying column 
overnight will lead to mostly clear skies with just some high clouds 
moving back in overnight.

&&

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

330 PM update...

Thursday...

Departing short wave across the maritimes in the morning, results in 
subsidence, dry weather and sunshine filtered by high clouds across 
SNE. Very mild start to the day, with sunrise temps 45-50, providing 
a high launching pad for highs tomorrow. Very weak CAA in the 
morning becomes neutral by 18z, then WAA late in the day ahead of 
approaching frontal wave. Model soundings indicate blyr mixing is 
fairly shallow, not quite to 925 mb. Given temps of +7C to +9C at 
the top of the mixed layer, highs of 60-65 are supportive across 
CT/RI and up to the Pike in MA, possibly into the city of Boston, 
with light WSW surface winds. 55-60 for highs across northern MA. 
This will be record warmth territory for Boston and Providence, with 
record highs Thu for both locations at 60 degs. Higher probability 
of PVD breaking the record than BOS, given proximity to frontal 
boundary and warm sector farther south into CT/RI and southeast MA. 

Morning sunshine fades behind increasing clouds with rain likely 
overspreading the region sometime between 3 pm and 6 pm from west to 
east, in response to the next pulse of thermal and moisture 
advection from approaching weak s/wv.  

Low level wind axis shifts east during the morning then the nose of 
a SW low level jet approaches the south coast toward 00z. Therefore, 
some wind early and late, with light winds midday.

Thursday night...

Another very mild night, as low pressure tracks northeast from PA to 
NY into northern-central New England, thus warm sector over SNE. 
Another night with lows only in the 40s. 12z guidance suggest best 
synoptic scale forcing and frontal convergence occurs after 12z Fri. 
Therefore, not a washout Thu night, appears to be scattered showers. 
Light south winds in the evening, shift to the SW and increase 
towards morning, 20-30 mph, strongest along/near the south coast, 
including Cape Cod and the Islands.  Increasing dew pts on SW flow 
across the cool ocean, may result in patchy fog along and near the 
south coast of MA/RI. 

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...

Highlights

* Above normal temperatures again on Friday will be accompanied by 
  rainfall ahead of an approaching cold front.

* Dry weekend with a seasonably cold Saturday followed by a more 
  mild Sunday.

* Wet/unsettled weather next week.

Friday

Area of low-pressure tracking north and west of southern New England 
will place the forecast region in an anomalously warm air mass 
characterized by 925 hPa temps above 10 Celsius. This will support 
another afternoon with temperatures in the 50s or perhaps even 60 at 
some locations. In addition to the warm temperatures, expect fog and 
widespread showers ahead of an advancing cold front. Also can't rule 
out a couple of rumbles of thunder as model forecast soundings 
support some elevated instability to the tune of around 100 J/kg of 
CAPE. A tight thermal/pressure gradient will support strong winds on 
Friday as well. Despite a 60 knot 925 hPa LLJ, a strong low-level 
inversion will limit southwest winds at the surface to 20 to 25 
knots with gusts of 30 to 35 knots across the interior. Stronger 
gusts from 35 to 40 knots will be possible across The Cape/Islands. 
As the front pushes through the region on Friday afternoon, winds 
will shift to the northwest with gusts from 20 to 30 knots across 
the region. May see a few snow showers on the back end of the front 
as precipitation tapers off from northwest to southeast during the 
evening hours.

Friday night through Sunday

Cooler/drier air mass filters in behind an exiting cold front Friday 
night with seasonably cold temperatures. Lows in the teens and 20s 
on Saturday morning with some wind chill values in the single digits 
across the northwestern regions. Seasonably cold temperatures 
Saturday afternoon are expected as well with 925 hPa temps around -5 
C supporting highs in the 30s to perhaps low 40s. Surface high 
pressure building off the east coast to our south will support dry 
weather. As the surface high slides east of the region by Sunday, 
southwesterly flow settles back in to support more mild temperatures 
in the upper 40s to perhaps low 50s on Sunday afternoon. Overall a 
quiet weekend weatherwise.

Next Week

Mild temperatures persist into Monday, but this will begin a cooling 
trend that will bring temperatures down to somewhat normal values 
for late February. A couple of short-waves will support 
wet/unsettled weather on Monday and then again on Tuesday night. 
This will be followed by a more robust low-pressure system that may 
bring substantial precipitation to portions of the Northeast mid to 
late next week. Confidence is low at this time, but ensemble 
guidance supports another inland track that would limit the 
potential for wintry precipitation. Still plenty of time for 
changes, so stay tuned for further details as we head into next week.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Forecaster Confidence Levels:

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

18Z TAF update: 

This evening and overnight...

VFR with brief periods of MVFR cigs. Dry weather with gusty SSW
winds 20-30 kt, slowly beginning to diminish 22z/23z, then
shifting to the west late at 5-15 kt. Areas of LLWS with low 
level jet 40-50 kt at 2 kft. 

Thursday...VFR, then cigs lowering to MVFR late, especially CT
valley as showers overspread the region from the west. SW winds
5-15 kt. 

Thursday night...MVFR/IFR in showers, drizzle and fog. SW winds
10-15 kt, gusts up to 30 kt over Cape Cod and Islands late. 

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF. 

Outlook /Friday through Monday/...

Friday: Mainly VFR, with areas IFR possible. Windy with gusts
up to 35 kt. RA likely, patchy BR.

Friday Night: Mainly VFR, with local MVFR possible. Windy with
gusts up to 35 kt. Slight chance RA.

Saturday through Sunday: VFR. Breezy. 

Sunday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance RA.

Washingtons Birthday: Mainly MVFR, with areas VFR possible.
Breezy. Chance RA.

&&

.MARINE...
Forecaster Confidence Levels:

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

340 PM update...

Tonight...high confidence.

Gusty SSW winds 20-30 kt diminish this evening, and become WSW after 
midnight. Dry weather and good vsby.

Thursday...high confidence.

Modest WSW winds 10-15 kt in the morning, diminishing in the 
afternoon, then becoming S toward sunset. Dry weather in the 
morning, with rain overspreading the waters roughly 3-6 pm west to 
east.   

Thursday night...high confidence.

As frontal boundary over central/northern New England descends 
southward, SW winds increase to 20-30 kt, possibly gusting up to 35 
kt. Therefore, Gale Watch remains posted. Scattered showers and fog 
likely lower vsby at times. 

Outlook /Friday through Monday/...

Friday: Low risk for gale force winds with gusts up to 40 kt.
Rough seas up to 10 ft. Chance of rain, patchy fog. Visibility
1 to 3 nm.

Friday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain. Local
visibility 1 to 3 nm.

Saturday: Winds less than 25 kt. Local rough seas. 

Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Seas up to 5 ft. 

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft. 

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain. 

Washingtons Birthday: Low risk for Small Craft Advisory winds
with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance
of rain. 

&&

.CLIMATE...

Record Highs for Thu 2/16...

Boston      60 in 1882 and 1910
Hartford    72 in 1954
Providence  60 in 1910
Worcester   62 in 1954

Record Highs for Fri 2/17...

Boston      61 in 1981 and 2022
Hartford    64 in 1981 
Providence  66 in 1981 
Worcester   59 in 2022


Record Highest Low Temperatures for Thu 2/16...

Boston      41 in 1976
Hartford    40 in 1984
Providence  41 in 1976
Worcester   37 in 2006

Record Highest Low Temperatures for Fri 2/17...

Boston      43 in 2022
Hartford    39 in 1981
Providence  45 in 2022
Worcester   42 in 2022

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 9 PM EST this evening for ANZ230-
     231-236-251.
     Gale Watch from late Thursday night through Friday afternoon 
     for ANZ231>235-237-250-254>256.
     Small Craft Advisory until 11 PM EST this evening for 
     ANZ232>234.
     Small Craft Advisory until 7 AM EST Thursday for ANZ235-237-
     250.
     Small Craft Advisory until 4 PM EST Thursday for ANZ254>256.

&&

$$
SYNOPSIS...Nocera/RM
NEAR TERM...Nocera
SHORT TERM...Nocera
LONG TERM...RM
AVIATION...Nocera/RM
MARINE...Nocera/RM
CLIMATE...