Old Res Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 021807
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
207 PM EDT Thu Apr 2 2026

.WHAT HAS CHANGED...
Forecast remains on track.

&&

.KEY MESSAGES...

- Chilly and damp at times rest of today into Friday morning,
  then turning much milder & drier Friday PM, with highs in the
  60s! 

- Backdoor cold front Sat brings falling temps into the 40s across 
  eastern MA...while the CT Valley might reach 65-70+.

- Southwest flow returns Sun with highs into the 60s for many 
  locales...but a period of widespread showers expected with 
  a cold front.

- Chilly temps for the first half of next week with mainly dry
  weather, but a brief period of rain/showers possible around
  Tue.

&&

.DISCUSSION...

KEY MESSAGE 1...Chilly and damp rest of today into Friday
morning, then turning much milder & drier Friday PM, with highs
in the low to mid 60s away from the south coast. 

1040 mb high over southeast Quebec provides cool air damming across 
SNE today, tonight and into Friday morning. Thus, chilly temps with 
most locations remaining in the 30s, with a stiff NE wind making it 
feel colder. As for precip, spotty light rain/drizzle in the cool 
sector, may become more widespread late tonight/early Fri AM, as WAA 
aloft increases with front lifting north. Most locations remain 
above freezing, however the highest terrain may dip to around 32. 
Therefore, there could be some light spotty freezing rain/drizzle at 
elevations above 500 ft. However, given such marginal temps and not 
covering much real estate, not expecting much if any impacts. Hence, 
no headlines necessary. As the warm front lifts north toward 
morning, there could be some areas of dense fog late tonight 
and then impacting the early morning commute Friday. 

Boundary south of New England today/Thursday, lifts north as warm 
front Friday afternoon. Good model agreement, including hi res 
guidance, that warm sector overspreads the region during the 
afternoon, with increasing sunshine and highs warming into the low 
and mid 60s across northern portion of CT/RI/MA and into the greater 
Boston area. Could be late day (after 4-5 pm) high temps, as low 
clouds may take some time to burn off. However, southwest flow and 
strong April sunshine will win out eventually away from the south 
coast. Much cooler across southern RI into southeast MA, as low 
clouds may only lift to higher cloud bases and not completely burn 
off. This combined with SSW wind trajectory off the cold ocean, 
highs here may only climb into the 50s, upper 40s Cape and Islands. 
Still much milder than today. Also, it will turn breezy Fri 
afternoon, especially away from the south coast in the afternoon, as 
temps warming into the low and mid 60s, will mix down SW winds 15-25 
mph.  

Precipitation...there could be some spotty light rain/drizzle in the 
morning as the warm front lifts north. Otherwise a dry afternoon. A 
cold front approaches from the west late in the day. There could be 
a few decaying showers exiting NYS that reach western MA/CT during 
the evening. Otherwise, dry weather prevails Friday evening and 
night. 

KEY MESSAGE 2...Backdoor cold front Sat brings falling temps into 
the 40s across eastern MA...while the CT Valley might reach 65-70+.

Low pressure will lift northeastward across the Great Lakes as large 
Canadian high pressure drops into the Maritimes on Sat. This will 
result in a backdoor cold front pushing westward across the region 
during the day Sat. Timing is tricky at this point...but temps 
should fall into the 40s across eastern MA by or during Sat 
afternoon. In fact...not out of the question temps drop into the 
upper 30s near the immediate eastern MA coast. Meanwhile...parts of 
western MA/CT may reach 65-70+ with the later arrival of the front. 
Keep in mind...these temps will be significantly impacted by a 2-4 
earlier/later passage of this front so changes may certainly be 
needed. 

Much of Sat may end up dry...but will have to watch for a few 
passing showers and perhaps some drizzle/fog behind the backdoor 
cold front. 

KEY MESSAGE 3...Southwest flow returns Sun with highs into the 60s 
for many locales...but a period of widespread showers expected with 
a cold front.

Low pressure lifts northeast across Quebec on Sun with a cold front 
extending southward from it. The shallow cool inversion should mix 
out on Sun ahead of the approaching cold front. This should allow 
highs to reach back into the 60s across many locations despite an 
abundance of clouds. We also expect a period of widespread showers 
on Sun as this cold front crosses the region. While these showers 
should be progressive...modest southerly LLJ/Pwat plume may result 
in brief downpours and even a rumble of thunder with the activity. 

KEY MESSAGE 4...Chilly temps for the first half of next week with 
mainly dry weather, but a brief period of rain/showers possible 
around Tue.

Ensemble model guidance in very good agreement in an upper trough 
building across the northeast for the first half of next week. This 
will result in chilly and mainly dry weather...but a period of 
rain/snow showers possible around Tue with a shortwave/mid level 
trough crossing the region. Highs Mon/Tue/Wed mainly in the middle 
40s to the lower 50s...but turning milder on Thu with southwest flow 
developing ahead of our next cold front. 

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

18z TAF Update...High confidence on trends, lower on exact timing.
 
Through Friday morning...persistence forecast a good bet here with 
IFR/MVFR cigs and MVFR/VFR vsbys in spotty light rain/drizzle 
through the period. Modest ENE winds 15-25 kt this afternoon, ease 
this evening and become SE overnight. 

Friday afternoon...IFR/MVFR cigs lifting to VFR across northern 
CT/RI/MA, including KBOS around 18z. Probably only improving to MVFR 
cigs south coast given SSW wind off the cold ocean. SW winds 
increase to 15-25 kt. Any morning drizzle/spotty light rain gives 
way to dry runways in the afternoon.  

Friday night...MVFR cigs may linger along the south coast, although 
mainly dry weather prevails. LLWS possible in the evening 
(WS020/24045KT) as surface winds diminish but low level jet lingers 
before exiting offshore overnight. 

KBOS Terminal...high confidence on trends, lower confidence on exact 
timing in TAF. Big picture, persistence is probably the best 
forecast for rest of today, tonight and into Fri AM, with IFR/MVFR 
cigs and MVFR/VFR vsbys in spotty light rain/drizzle. Modest ENE 
winds ease this evening, then become SE overnight. Big improvement 
Friday after 18z to VFR, dry wx and SW winds 15-20G25kt. LLWS 
possible Friday evening, as surface winds ease but low level SW jet 
persists (WS020/24045KT possible beginning 00z Sat).  

KBDL Terminal...High confidence in trends, lower in exact timing 
details. Overall, MVFR cigs and VFR vsbys in spotty light 
rain/drizzle through Fri AM. Then VFR after 16z Friday, along with 
dry weather and modest SW winds 15-20G25kt.

Outlook /Saturday through Tuesday/...

Saturday: Mainly VFR, with local MVFR possible. Breezy. Slight
chance SHRA.

Saturday Night: Mainly MVFR, with areas IFR possible. Breezy.
Chance SHRA, patchy BR.

Sunday: Mainly MVFR, with areas IFR possible. Windy with gusts
up to 35 kt. SHRA likely.

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

Monday: VFR. Breezy. 

Monday Night: VFR. 

Tuesday: Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

2 PM update...High confidence through Friday night.

1040 mb high over southeast Quebec provides chilly ENE winds across 
the MA/RI waters Thu afternoon. As the high noses southward, gusty 
ENE winds slacken Thu evening and become SE overnight. Despite winds 
slackening, seas will take sometime to subside. Thus, SCAs continue. 
Boundary south of New England Thursday, lifts north as a warm front 
Friday, accompanied by a wind shift to the SW at speeds 15-20 kt, 
gusting up to 25 kt at times. Before the frontal passage, areas of 
dense fog are possible along and ahead of the warm front late 
tonight into Friday morning. Improved vsby and drier weather Fri 
afternoon. Tranquil and dry weather Friday night, as a weak and 
decaying cold front approaches the waters from the NW.

Outlook /Saturday through Tuesday/...

Saturday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft. Patchy fog. 

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain
showers, patchy fog. 

Sunday: Low risk for gale force winds with gusts up to 35 kt.
Rough seas up to 11 ft. Rain showers likely. 

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Chance of rain showers.

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

Monday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. 

Tuesday: Winds less than 25 kt. Slight chance of rain showers. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for 
     ANZ231>234-251.
     Small Craft Advisory until 11 PM EDT this evening for ANZ235-
     237.
     Small Craft Advisory until 6 AM EDT Friday for ANZ250.
     Small Craft Advisory until 2 AM EDT Friday for ANZ254>256.

&&

$$

DISCUSSION...Frank/Nocera
AVIATION...Frank/Nocera
MARINE...Frank/Nocera