Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Overcast
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

Southeast Middlesex County, MA - High Wind Warning
- SEE ALL NEARBY ALERTS -

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 161856
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
256 PM EDT Mon Mar 16 2026

.WHAT HAS CHANGED...
High Wind Watches have been upgraded to High Wind Warnings across 
eastern MA and RI.

&&

.KEY MESSAGES...

- Periods of heavy rain with embedded t-storms today, especially 
tonight, may lead to river and small stream flooding. Poor drainage 
in urban areas could flood as well.

- A period of strong to damaging winds across SNE tonight. 

- Mainly dry and trending colder Tue into Wed.

- After a cold start early Thu morning temps begin moderating 
  especially by Fri. Mainly dry weather over this time.

- Unsettled weather at times Fri night into early next week...
  but timing remains uncertain. Temps tricky this weekend
  depending on the location of a boundary in the vicinity of
  SNE. Temps trending colder than normal early next week. 


&&

.DISCUSSION...

KEY MESSAGE 1...Periods of heavy rain with embedded t-storms today, 
especially tonight, may lead to river and small stream flooding. 
Poor drainage in urban areas could flood as well.

We're in the thick of a wet and windy storm system that will 
continue to impact the region through sunrise on Tuesday. After a 
bout of heavy and widespread rainfall this morning we're in a 
relative lull this afternoon as the warm front has lifted into 
northern New England. This has placed us into a warm and moist 
airmass with temperatures as warm as the low 60s while dewpoints 
have risen well into the 50s. A very strong LLJ (80-90 kts at 925mb 
over southeast MA) will act on very anomalous moisture (PWATs near 
1.5" or 3-4 SD higher than normal) to continue to squeeze out 
copious amounts of rainfall over the next 12-15 hours. Following 
this lull in intensity we'll see a resurgence of heavy rainfall this 
evening and overnight ahead of the cold front. Rainfall amounts will 
also be juiced by any convection that occurs given the environment 
with 400-600 J/kg of elevated CAPE. The best chance for thunder is 
CT/RI and central MA. When all is said and done still expecting 
widespread 2 to 3 inches of rain with 3-4 inches possible in those 
locations that experience a t-storm. River Flood Warnings have been 
issued for some area rivers, given recent snowmelt combined with a 
decent rainfall will lead to minor flooding. Additionally, some 
localized poor drainage flooding is possible, especially under any 
convection. 

KEY MESSAGE 2...A period of strong to damaging winds across SNE 
tonight. 

The other threat from this system is a period of strong, potentially 
damaging winds. As was mentioned previously, the jet dynamics with 
this system are very strong. This means we'll have an impressive low 
level jet screaming overhead just above a temperature inversion. 
Model soundings show an impressive inversion to near 950 mb which is 
typical this time of year with southerly wind events. The question 
is always just how much of that jet can be tapped into to pull down 
to the surface. The best way to tap into these winds is typically 1) 
warming the surface, the warmer the temp the better mixing and 2) the 
winds being pulled down by heavy downpours, especially in 
convection. The best shot for this event will be a fine line of 
convection accompanying the cold front after midnight tonight 
coincident with the core of the jet overhead. Thus, while winds will 
be increasingly gusty today, gusting 35-45 mph by the evening, the 
real chance for damaging winds will be in a ~3-4 hour window from 
roughly midnight to 4am. Wind gusts as high as 65 mph are possible 
in the southeast MA/RI area. Can't even rule out a gust to 70 mph in 
the Providence to Plymouth corridor. This is the favored location 
because, while the core of the jet is further south over the 
Cape/islands, southerly flow off the water keeps temperatures cooler 
in these areas so mixing isn't as efficient. 

KEY MESSAGE 3...Mainly dry and trending colder Tue into Wed. 

The cold front exits east offshore well before sunrise on Tuesday 
ushering in a cooler and drier airmass through Wednesday. Expect 
mostly sunny skies mixed with some diurnal cumulus thanks to the 
cold pool that moves in aloft. 925 mb temps drop from 13 C on Monday 
to -3C on Tuesday so we can expect a significant cooldown, 10-15 
degrees in highs from Monday to Tuesday and even moreso on 
Wednesday. Highs Tuesday will be in the low to mid 40s while 
Wednesday will be in the 30s. 

KEY MESSAGE 4...After a cold start early Thu morning temps 
begin moderating especially by Fri. Mainly dry weather over this
time.

Large high pressure shifts east of the region Wed night & Thu. 
Conditions will still be favorable for a good night of radiational 
cooling Wed night...so expect low temps mainly in the teens and 20s. 
Return southerly flow and plenty of March sunshine should allow 
highs on Thu to recover back into the low to mid 40s by afternoon. 

A warm front crosses the region late Thu night into early Fri 
morning with perhaps a brief passing rain/snow shower or two. 
Otherwise...expect a further moderation in temps with highs on Fri
potentially 50+. 

KEY MESSAGE 5...Unsettled weather at times Fri night into early
next week...but timing remains uncertain. Temps tricky this 
weekend depending on the location of a boundary in the vicinity 
of SNE. Temps trending colder than normal early next week. 

A couple pieces of northern stream shortwave energy will result in 
unsettled weather at times Fri night into early next week. Specific 
timing is uncertain...but appears one potential for showers will be 
Fri night/early Sat associated with a shortwave/cold front. Perhaps 
another round of unsettled weather later this weekend into early 
next week...but timing/confidence on that is low given a large model 
spread in timing and track.

A boundary in the vicinity of southern New England makes the 
temperature forecast tricky this weekend. Highs may be in the upper 
30s and 40s north of the boundary and between 55 and 65 to the south 
of the boundary. We probably will end up mostly on the cooler side 
of those numbers especially in north/northeast MA given climo this 
time of year...but plenty of time to sort that out. 
Regardless...temps likely trending colder early next week given 
amplifying New England upper trough indicating by the long range 
ensembles.



&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

18Z update...

This afternoon...High Confidence

IFR. Southerly winds gusting 30-35 kts late afternoon and 
evening. Scattered TSRA is increasingly likely particularly in 
CT and RI into northeat MA. 

Tonight...High Confidence. 

Peak of the winds, gusting gusting 40-55kts for several hours. 
S winds become more SW and W by 12Z. RA/TSRA possible through 
07-12z, ending from west to east. 

Tuesday...High Confidence

VFR. Region clears out behind cold front. Gusty W winds around 
25-30 kt are left in its wake.

Tuesday night...High Confidence. 

VFR. W winds 5-10 kts. 

KBOS Terminal...Moderate confidence.

KBDL Terminal...Moderate confidence.

Outlook /Wednesday through Saturday/...

Wednesday through Wednesday Night: VFR. 

Thursday: VFR. Breezy. 

Thursday Night: VFR. Slight chance SHSN.

Friday: VFR. Slight chance SHRA.

Friday Night: VFR. Chance SHRA, chance SHSN.

Saturday: VFR. Breezy. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday night...

Winds ramp up this afternoon into tonight as a powerful low pressure 
system approaches from the west. Seas increase considerably headed 
into tonight, reaching up to 15 ft and even close to 20 ft in the 
southern waters by 06z Tuesday. Seas 7-10 ft will be more common in 
the eastern waters. Winds will very likely reach storm conditions 
tonight. Storm Warnings are in effect for all waters. 

Seas decrease to around 12 ft for Tuesday as the cold front exits 
over the waters. W winds remain gusty to around 35 kt through the 
day Tuesday. Winds and seas diminish significantly Tuesday night. 

Outlook /Wednesday through Saturday/...

Wednesday: Winds less than 25 kt. Areas of rough seas. 

Wednesday Night: Winds less than 25 kt. Seas up to 5 ft. 

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

Friday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers. 

Friday Night through Saturday: Winds less than 25 kt. Seas up
to 5 ft. Chance of rain showers. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch through Tuesday morning for CTZ002>004.
     Wind Advisory until 8 AM EDT Tuesday for CTZ002>004.
MA...Flood Watch through Tuesday morning for MAZ002>022-026.
     Wind Advisory until 8 AM EDT Tuesday for MAZ002>004-008>012-
     026.
     High Wind Warning until 6 AM EDT Tuesday for MAZ005>007-
     013>024.
RI...Flood Watch through Tuesday morning for RIZ001>007.
     High Wind Warning until 6 AM EDT Tuesday for RIZ001>008.
MARINE...Storm Warning from 8 PM this evening to 5 AM EDT Tuesday for 
     ANZ230-236.
     Storm Warning until 8 AM EDT Tuesday for ANZ231>235-237-250-
     251-254>256.

&&

$$

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