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 120607
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
207 AM EDT Thu Mar 12 2026

.WHAT HAS CHANGED...
Small Craft Advisories extended for some waters into Friday. 
Cold front moving across our region late tonight into Friday  
could allow for hit-or-miss showers or even a rumble of thunder
tonight for some.

&&

.KEY MESSAGES...

- Cold front moves across our region late tonight into midday
  Thursday. Expecting falling temperatures through the day. Even
  a risk for minor snow accumulation across interior southern
  New England, depending on the timing of the subfreezing air. 

- Light snow Friday PM. Minor accumulations possible for higher 
  elevations. Gusty winds Saturday. 

- Widespread rain with locally heavy rainfall Sunday night into 
  Monday which may lead to minor river flooding. Another period 
  of gusty winds Monday.

&&

.DISCUSSION...
KEY MESSAGE 1...Cold front moves across our region late tonight
into midday Thursday. Expecting falling temperatures through the 
day. Even a risk for minor snow accumulation across interior
southern New England, depending on the timing of the subfreezing 
air.

Much of our weather into Thursday will depend on the timing of 
a cold front moving past southern New England. Expecting 
scattered showers for most, with the possibility of a 
thunderstorms closer to the cold pool aloft moving across the 
Great Lakes into northern New England. Once this front moves on 
by, colder air should arrive. Air cold enough to result in 
falling temperatures during the daytime. That said, expecting 
low temperatures to return to near normal for mid March by 
Thursday night.

Thinking showers will be most widespread across our region after
midnight into mid morning Thursday. Depending on how quickly
temperatures fall, there is the possibility for light snow
across the higher terrain towards the Berkshires mainly, but
perhaps also into the Worcester Hills. Conditions should be
drying as this snowfall develops, so not expecting much more
than a coating to an inch. 


KEY MESSAGE 2...Light snow Friday PM. Minor accumulations
possible for higher elevations. Gusty winds Saturday. 

Mainly dry conditions expected on Friday with seasonable
temperatures. Next shortwave trough is expected to move through 
the region Friday night into Saturday. Model guidance shows a 
signal for marginal moisture to push into the region ahead of 
the wave. Scattered showers are possible Friday afternoon and 
Friday night. These showers are more likely to be snow showers 
for the high elevations. Rain/snow mix is possible for the lower
elevations. Any accumulations are likely to be light. Generally
up to an inch for northwest/north-central MA higher elevations,
perhaps locally higher amounts for the highest elevations of 
the northern Berkshires. Elsewhere, a coating to a half an inch 
is more likely for the remainder of MA, northern CT (excluding 
the Cape). A cold front swings through overnight into Saturday 
morning. A moderate jet and enhanced gradient along with CAA 
will allow mixing down of stronger winds aloft to the surface. 
There is some uncertainty among guidance on how strong the jet 
will be. Gusts 35-45 mph are possible with the higher winds 
across the higher elevations and Cape/Islands. There are 
moderate probabilities 50-60% for gusts greater than 45 mph for 
the highest terrain of the Berkshires and Worcester Hills. 
Something that we will have to keep an eye on for potential Wind
Advisory headlines. 


KEY MESSAGE 3... Widespread rain with locally heavy rainfall
Sunday night into Monday which may lead to minor river flooding. 
Another period of gusty winds Monday. 

A shortwave trough approaches the region Sunday with a LLJ ahead
of it. This will shift winds southwest and help advect in
moisture rich air northward into southern New England. Moisture 
will be fairly above normal with precipitable water amounts 
200-280% of normal. Marginal instability associated with this 
system along-side the anomalous precipitable water values raises
the potential for locally heavy rainfall, convective cells, and
perhaps an isolated thunderstorm embedded in the rain. Ensemble
probabilities for greater than 1" of rain range from 30-60% 
generally. The ECMWF ensemble members are leaning wetter than 
the GEFS, even highlighting higher probs closer to 70% for RI, 
CT, and SE MA for 1" or greater of QPF. Upper percentiles for 
total QPF run 1 to a little over 2" across ensemble guidance. 
This does raise concern for rising river/stream levels from 
snowmelt and additional rain. MMEFS ensemble guidance shows 
potential (40-60%) for rivers reaching minor flood levels early 
next week (Pawtuxet, Taunton, Pawcatuck rivers). Low probs to 
reach minor flood along the lower reaches of the mainstem 
Connecticut River from Hartford through Middle Haddam. 

A strong southerly LLJ shifts across the region Monday. This
will produce gusty south winds. There is uncertainty in the
degree of mixing we will get to the surface from that LLJ, so
the magnitude of gusts remains less certain. Regardless, it 
will likely be generally gusty Monday with milder temperatures.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

00z TAF Update: 

Today: Moderate confidence. 

This is a pretty active, changeable aviation forecast period.

Mix of flight categories from VFR to LIFR, lowest along the
south coast due to dense fog. Still have areas of showers/TS 
but this activity should be moving northeast through 08-10z. 
Brief clearing from west to east between 08-12z with categories 
in the VFR-MVFR range for most airports by morning. Southerly 
winds around 10-15 kt with gusts 20-25 kt with continued low
level wind shear.

A cold front will then be moving through SNE between 12-16z 
Thurs west to east, which will bring a gusty windshift to WNW 
around 15-18 kt with gusts 25-30 kt. Cooling temperatures will 
allow for initial rain, but rain should then mix with PL and 
then SN with MVFR visby/MVFR-IFR ceilings from ~18-00z. Up to 
an inch of snow accum possible on grassy surfaces although 
runways should be wet given preceding spell of warm 
temperatures. 

Tonight: High confidence. 

Rapid improvement to VFR early tonight. NW winds around 10 kt
with occasional gusts to 20 kt. Even though temperatures will 
be subfreezing, rapid drying should limit any freeze-up on 
runways.

Friday: High confidence. 

VFR, though with increasing midlevel clouds late in the day. NW
winds become light and then shift to SW around 5-10 kt.

KBOS Terminal...Moderate confidence. SHRA thru 09z Thurs with
period of brief dry weather but MVFR/VFR ceilings around. A
gusty windshift to NW takes place 13-15z. Cooling temps after 
18z then brings a risk for rain mixed with PL then brief SN.
Visbys 2-4 SM in wintry precip, although runways should be wet.
Rapid VFR improvement by early this evening.

KBDL Terminal...Moderate confidence. SHRA, embedded TS possible
thru 08z. VFR/MVFR ceilings after 08z before cold front brings 
resuming risk for rain and a gusty NW windshift after 13z. 
Cooling temps could support mixover to PL then SN after 17z 
Thurs, ending by 00z. 

Outlook /Friday through Monday/...

Friday: VFR. Breezy. Slight chance RA.

Friday Night: Windy with local gusts up to 30 kt. Chance RA.

Saturday: Windy with gusts up to 30 kt. 

Saturday Night: Breezy. 

Sunday: Breezy. Slight chance RA.

Sunday Night: Strong winds with local gusts up to 40 kt. Chance
RA, chance FZRA, slight chance TSRA.

Monday: Strong winds with areas of gusts up to 45 kt. RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Rough seas linger across the outer coastal waters into Friday
morning. A cold front moving across the waters late tonight into
Thursday will also generate gusty SW winds at times until it
passes. Poor visibility at times in fog expected tonight, and
also the risk for a few showers. Becoming clearer with gusty W
to NW winds Thursday into Thursday night.

Outlook /Friday through Monday/...

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

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

Saturday: Strong winds with gusts up to 35 kt. Rough seas up to
11 ft. 

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. 

Sunday: Winds less than 25 kt. 

Sunday Night: Strong winds with gusts up to 40 kt. Areas of
rough seas. Rain likely, slight chance of thunderstorms. 

Monday: gale force winds with gusts up to 45 kt. Rough seas up
to 13 ft. Rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ232-
     233.
     Small Craft Advisory until 1 PM EDT this afternoon for ANZ234.
     Small Craft Advisory until 7 AM EDT Friday for ANZ235-237-250-
     254>256.

&&

$$

DISCUSSION...Belk/Mensch
AVIATION...KJC/Loconto
MARINE...Belk/Mensch