Lexington Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 100835
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
335 AM EST Mon Nov 10 2025

.SYNOPSIS...
Overcast conditions with above normal temperatures today. A 
cold front will bring a period of rain showers today, then
decreasing clouds later in the day. Sharply falling temperatures 
tonight, with the first taste of winterlike temperatures 
settling in tonight and into Tuesday. Wind chills on Tuesday 
could be as low as the upper teens to the 20s on gusty northwest
winds. Slight improvements in temperatures Wednesday as a 
shortwave rotates through the area. Cooler weather with 
continued troughing through the end of the workweek. 

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
315 AM Update:

Key Messages: 

* Foggy, misty overcast this morning; overcast much of today 
  but some decrease in clouds late. 

* Light rain showers with cold front passage mid morning to mid 
  afternoon from west to east. Additional spotty precip in the Berks 
  could be cold enough for brief snowflakes late this afternoon. 

* Current temps upper 40s to upper 50s are today's highs, with 
  not much net change in temps, but will be falling by sundown 
  in the Berkshires.
  
Details:

By mid-November standards, it's an anomalously mild early morning 
across Southern New England, as a subtropical feed of moisture is 
being advected northward in deep SSW flow aloft across the 
Northeast. This is ahead of an impressive upper level low centered 
in the vicinity of Chicago, associated with an early-season outbreak 
of winter-like air which extends into the Deep South! Current temps 
in Southern New England are in the 50s, with some upper 50s/near 60 
in southeast New England. By comparison, as of this AFD, Atlanta GA 
is 40 degrees with a NW wind gusting to 35 knots. We are also 
socked in with low-level moisture trapped beneath a dry punch of
air in midlevels, and is contributing pretty widespread mist, 
fog and at times some areas of drizzle. We've issued an SPS for 
foggy conditions through 5 AM to address any travel 
difficulties, as reduced visbys (generally half to 4 miles, but 
could be as low as quarter mile in spots) are likely to persist 
into part of the morning. 

Looking likely we'll remain in this dreary overcast for some 
time today. But a strong cold front is right on our doorstep, 
producing a shield of light to moderate rain showers from the 
Hudson Valley on southward into NJ. Some improvement to visbys 
is expected as the front and rain showers overspread; it's a 
messy frontal passage, but a best estimate on arrival of rain 
showers is around 4-7 AM in far western New England and the 
Berkshires, around 10-noontime in central MA, into eastern MA 
and RI around noon to 2 PM and making it offshore by sundown. 
Should see cloud cover then start to scatter and lift but 
today's a generally mostly cloudy to overcast day. There may be 
additional light precip behind the cold front in interior 
western New England into the afternoon, which could include some
backside light snow showers later in the day into the western 
hilltowns of the Berkshires but these would be more 
novel/decorative than causing impacts as the colder air starts 
to work its way in. 

After the cold front moves through, the truly cold air will only 
gradually ooze in. Highs for the day have already occurred or are 
occurring, but temperatures most of today won't really change all 
that much, until we get to late this afternoon in the Berkshires. So 
we should see temperatures today in the 50s. But the bottom will be 
falling out with the temperatures after sundown in all areas, with 
the first real taste of winter-like temperatures arriving tonight 
and especially Tuesday. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
315 AM Update:

Key Messages: 

* Winterlike temps arrive tonight: upper 30s to low-mid 50s 
  early tonight crash to widespread subfreezing readings by 
  dawn.

* Partly cloudy Tue, but with below normal temps and gusty NW winds 
  producing a biting cold. Highs in the 30s (sub-freezing highs in 
  the terrain), but will feel like the mid teens to the 20s in most 
  areas, with NW gusts 30-40 mph.

* Intervals of snow showers in the terrain Tue afternoon, but nil 
  accumulation.

Details: 

Tonight: 

Surge of strong low-level cold advection takes place tonight, to go 
along with rapid drying and increasing WNW winds. 925 mb temps start 
out around -2 to 0C in the Berkshires, and around +2 to +10C 
elsewhere, warmer east. By morning, 925 mb temps in all areas are in 
the -5 to -7C range. Starting tonight in the mid 30s in the 
Berkshires to the 40s central sections to lower 50s near the 
coast. By midnight, much of the interior will be in the mid 20s 
to around freezing, and turns to widespread subfreezing temps to
the coast by dawn. 

Westerly winds will accompany this surge in colder air, and we 
should see wind chills between 4 and 7 AM in the mid to upper teens 
in the terrain, and the low to mid 20s for the lower elevations and 
coastal plain, and around freezing for the Cape and Islands. 

Tuesday / Veterans Day: 

The cold upper trough gradually lifts out toward the ENE 
through the day. This will allow for an enhanced westerly flow 
with partly to mostly cloudy skies (more clouds toward the west
due to advection of Great Lakes-enhanced moisture). The 
anomalously cold air will steepen lapse rates considerably, with
potential for mixing depths up to 800 mb.

The net result for Tue is anomalously cold daytime temperatures
with gusty northwest winds making for a biting cold. Ambient 
air temps only rise a few degrees, with ineffective warming 
from partial sun offset by the cold air, leading to high temps 
in the upper 20s/around freezing for the terrain, and the mid to
upper 30s for most of Southern New England (around 40 near the 
south coast, Cape and Islands). Mixed-layer speeds at the top 
of the deep boundary layer are as high as 45 kt, so gusts in the
30 to 40 mph range are conceivable with sustained west winds 
around 15-20 mph. Wind chills in most areas are in the 20s, with
mid to upper teens in the terrain! Add a couple layers for this
winterlike chill if you're headed outside. 

Weak lift in a saturated dendrite growth layer out in the 
Berkshires and into the MA portion of CT Valley Tue aftn could 
result in periodic, unfocused snow showers, given Froude 
numbers around 1 to 2 favoring unblocked terrain flow. But even 
with the cold air, pavement temps are still too warm for any 
impacts, so more likely to be decorative at worst. 

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Key Messages...

* Cold and blustery Tuesday night.

* A few rain and elevation snow showers possible Wednesday. 

* Increasingly dry with a moderating trend in temps through the 
  late week period. 

Another cold night Tuesday night for much of the CWA. Lows will 
moderate compared to Monday night owing to a well mixed boundary 
layer and increasing mid and high clouds. Temperatures Tuesday night 
fall into the upper 20s in the terrain and the middle to lower 30s 
for other areas.

Recent runs of CAMs have come in quite a bit more amplified with a 
shortwave rotating through the region on Wednesday. The result 
should be greater coverage of precipitation and cloud cover for much 
of the day. Expecting a warmer day as the flow becomes southerly. 
Highs will likely climb to near 50 near the coast but may be quite a 
struggle to get out of the 30s in the higher terrain. Elevated areas 
may see snow scattered showers through Wednesday afternoon with 
plenty of moisture and forcing. 

We'll feel the influence of a lingering trough over the northeast 
through the rest of the workweek keeping temperatures cooler than 
average generally in the upper 40s. A few weak disturbances round 
the trough leading mainly to some orographic rain/snow showers and 
ocean effect showers offshore, but the column remains largely dry 
which should prevent any widespread precipitation for the week and 
into the weekend as a brief ridge approaches around the weekend.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

06Z TAF Update: 

Tonight: High confidence in trends but moderate on timing.

Continued IFR-LIFR ceilings with FG/BR and -DZ. Winds turn 
toward SE/S overnight possibly becoming light and variable
through the early morning.

Monday: Moderate confidence. 

IFR-LIFR to start. Another batch of rain moves through ahead of
the cold front generally from west to east. Rain likely arrives
10-12z across the western terminals and closer to 14-16 further
east. Frontal passage 15-22z with ceilings quickly improving 
behind it. Windshift to W around 10-12 kt with frontal passage. 

KBOS Terminal...Moderate confidence in TAF.
IFR/LIFR conditions through the rest of the night into the
morning hours. Another round of showers with slight improvements
in ceilings arrive 14-16z Monday. FROPA 20-22z with ceilings 
improving to MVFR behind it.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Tuesday Night through Friday/... 

Tuesday Night: VFR. Windy with gusts up to 35 kt. 

Wednesday: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 30 kt. Slight chance RA.

Wednesday Night through Thursday: Mainly VFR, with local MVFR
possible. Breezy. 

Thursday Night through Friday: VFR. Breezy. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Key Messages: 

* SCAs still valid thru 12z Tue, but these are for seas in the
  5-7 ft range which will be slow to subside. 

* Foggy conditions especially this morning reduce visby, with
  periods of rain by mid-morning, clearing late afternoon. 

* Gale force westerly gusts on all waters Tue into part of Wed.
  Gale Warnings in effect for Tue into early Wed.

Seas are still elevated this morning and will only slowly
subside through tonight. Therefore SCAs were extended through
Monday night. Light winds this morning to gradually become W
with an increase in speeds to around 10-15 kt with gusts 20 kt
late this afternoon and tonight, as a cold front crosses the
waters. 

An anomalously cold airmass over the waters with a strong WNW 
pressure gradient will allow for gale force gusts to then 
develop by Tuesday and linger into at least part of the first 
half of Wednesday. Given high confidence, Gale Watches have 
been converted to Gale Warnings on all waters for this Tue- Wed 
period. Gusts 35-40 kt are expected with seas building to around
12-14 ft over the offshore waters. 

Outlook /Tuesday Night through Friday/... 

Tuesday Night: Strong winds with gusts up to 40 kt. Rough seas
up to 14 ft. 

Wednesday: Strong winds with gusts up to 35 kt. Rough seas up
to 13 ft. Chance of rain. 

Wednesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas. Slight chance of
rain. 

Thursday: Moderate risk for Small Craft Advisory winds with
areas of gusts up to 30 kt. Areas of rough seas. Slight chance
of rain. 

Thursday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas. Slight chance of
rain. 

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Local rough seas. Slight chance of rain. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Warning from 7 AM Tuesday to 7 AM EST Wednesday for 
     ANZ230-236.
     Small Craft Advisory until 1 PM EST this afternoon for ANZ231-
     251.
     Gale Warning from 7 AM Tuesday to 1 PM EST Wednesday for 
     ANZ231>235-237-250-251-254>256.
     Small Craft Advisory until 7 AM EST Tuesday for ANZ235-237-250-
     254>256.

&&

$$

SYNOPSIS...Loconto/FT
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...FT
AVIATION...Loconto/FT
MARINE...Loconto