Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Clear
Temperature: 35.1°F / 1.7°C
Dew Point: 32.4°F
Relative Humidity: 90%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.00 in Falling Slowly
Visibility: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 091035
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
635 AM EDT Mon Mar 9 2026

.WHAT HAS CHANGED...
No significant changes to the forecast. High confidence in near 
record high temperatures on Tuesday.

&&

.KEY MESSAGES...

- Area of fog quickly dissipate by mid-morning.
  Otherwise...sunshine returns today & Tue with well above
  normal temps. Highs mainly in the 60s today & near record
  highs Tue in the upper 60s to lower 70s away from parts of the
  immediate coast.

- Trending more unsettled mid to late week with a round or two of 
precipitation. Back to cool temperatures by Friday.

- Expecting significant snowmelt over the coming week. Minor
  river flooding possible.

&&

.DISCUSSION...
KEY MESSAGE 1...Area of fog quickly dissipate by mid-morning. 
Otherwise...sunshine returns today & Tue with well above normal 
temps. Highs mainly in the 60s today & near record highs Tue in the 
upper 60s to lower 70s away from parts of the immediate coast.

Areas of fog covered the region early this morning especially near 
the south coast where it was locally dense. The fog will quickly 
burn off after sunrise given a lot of dry air just above the 
boundary layer.

Unlike the weekend...model soundings indicate lots of sunshine today 
and Tue. This will allow that anomalous warmth in the 850/925 mb 
layers to begin to mix down to the surface. 925T around +10C today 
should allow many locations to see highs well into the 60s. Mainly 
clear skies & light winds will still allow for another good night of 
radiational cooling tonight. Low temps tonight should bottom out in 
the upper 20s & 30s...but lower 40s in the Urban Heat Island of 
Boston as well as Worcester airport given the anomalous warm air 
aloft.

By Tue...925T near +14C should allow for near record high temps in 
the upper 60s to the lower 70s! We feel that given the overall 
setup...the NBM is significantly too cool with the high temps today 
and Tue. Of course it will be noticeably cooler on the immediate 
south coast, Cape and Islands given the modified marine airmass 
given S-SW winds. We may also need to watch for a subtle sea breeze 
potential on Tue on parts of the immediate eastern MA coast...but 
that remains uncertain. All in all...well above normal 
temps/springlike weather is on tap for the next two days with near 
record highs possible on Tue. 

KEY MESSAGE 2...Trending more unsettled mid to late week with a 
round or two of precipitation. Back to cool temperatures by Friday.

After a dry and sunny few days Wednesday will be a transition day 
between early week ridging and a shortwave trough that crosses the 
region on Thursday. Ahead of said trough warm SW flow continues, 
keeping temperatures elevated. However, increasing moisture moves 
north as well so the clouds return keeping a check on temps, only 
reaching the upper 50s to low 60s. A caveat is that in extreme 
northeast MA a backdoor cold front may reduce temperatures further. 
A weaker leading wave moves through on Wednesday increasing the 
chance for scattered rain showers, mainly over the interior. It 
isn't until Thursday that the main trough and robust cold front move 
through. Favorable placement beneath the RRQ of a 150kt 300 mb jet 
combined with a 65kt LLJ will work on a moist environment (PWATs 
near 1.25") to produce widespread precipitation Thursday into 
Thursday night. It likely starts as rain for all before 
transitioning to snow on the back end for the high terrain. 

Friday the post frontal airmass overhead means cooler temperatures, 
in the 40s. Another disturbance passing to our north may bring some 
scattered rain/high elevation snow showers around Friday night but 
confidence is low in specifics on how the pattern evolves beyond 
Thursday. 

KEY MESSAGE 3...Expecting significant snowmelt over the coming week. 
Minor river flooding possible.

Given the prolonged period of elevated temperatures/dewpoints, 
combined with the significant melting we've seen the last few days, 
snowmelt will increasingly contribute back to the watershed leading 
to rises, potentially into minor flood stage. Guidance continues to 
indicate the most likely spots to see flooding are along the 
Connecticut River by next weekend with addition of S. RI rivers by 
early next week.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

12z TAF Update: High confidence.

IFR/LIFR in fog will lift quickly just after sunrise, but will
likely take until late morning or early afternoon near Cape Cod
and the Islands due to persistent S/SW flow. It's possible the 
fog may not completely burn off near ACK but we will show a 
window of improvement early this afternoon before LIFR quickly 
returns there and on Cape Cod late this afternoon and lasts 
through tonight. Elsewhere we expect another night of patchy 
valley fog with more brief IFR conditions. VFR Tue with S/SW 
flow, but a similar situation near Cape Cod and Islands where
fog may not completely burn off.

Other concern is for a period of LLWS in central/eastern MA and
RI from late afternoon until just past midnight, as SW winds at
2000 ft increase to around 40kt.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday: VFR. Patchy FG.

Tuesday Night: VFR. 

Wednesday: Mainly VFR, with local IFR possible. Breezy. Chance
RA.

Wednesday Night: MVFR/IFR conditions possible. Windy with local
gusts up to 30 kt. Chance RA.

Thursday: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 30 kt. Chance RA.

Thursday Night: Windy with local gusts up to 30 kt. Slight
chance SN.

Friday: Breezy. Slight chance SN.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Tuesday...High confidence.

The last of the lingering small craft swell should finally drop 
below criteria across our southern outer-waters by mid-late morning. 
Otherwise...a weak pressure gradient will keep winds and seas below 
small craft advisory thresholds through Tue. Areas of fog...some of 
which will be dense at times will impact our southern waters during 
the overnight and early morning hours. This will result in poor 
vsbys for mariners at times.

Outlook /Tuesday through Friday/...

Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Patchy fog. Areas of visibility 1 nm or less.

Tuesday: Winds less than 25 kt. Patchy fog. Local visibility
1 nm or less.

Tuesday Night: Winds less than 25 kt. 

Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain. 

Wednesday Night: Strong winds with gusts up to 35 kt. Areas of
rough seas. Chance of rain. 

Thursday: Strong winds with gusts up to 30 kt. Rough seas up to
13 ft. Chance of rain. 

Thursday Night: Strong winds with gusts up to 30 kt. Areas of
rough seas. Chance of rain, slight chance of snow. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for 
     ANZ254>256.

&&

$$

DISCUSSION...Frank/BW
AVIATION...JWD
MARINE...Frank/BW