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

Southeast Middlesex County, MA - Heat Advisory
- SEE ALL NEARBY ALERTS -

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 091913
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
313 PM EDT Tue Jun 9 2026

.WHAT HAS CHANGED...
Showers and storms may return Wednesday evening as a warm front 
approaches the region. No major changes otherwise.

&&

.KEY MESSAGES...

- Dry through the rest of today and tonight before the risk for
  showers and thunderstorms returns Wednesday afternoon/evening.

- Diurnal showers and thunderstorms possible Wednesday through
  Friday. Above normal temperatures peaking Thursday into Friday.

- Warm conditions with lower humidity throughout this weekend. 
  Uncertainty remains high regarding potential rain showers for 
  Saturday, and again early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Dry through the rest of today and tonight before the 
risk for showers and thunderstorms returns Wednesday 
afternoon/evening.

High pressure south of Long Island continues moving off to the south 
and east as the ridge aloft starts receding from the northeast US. 
Some shortwave disturbances will then start to make their way across 
the region as its influence wanes, which will aid in the return of 
some showers and storms. Lows tonight will generally be in the upper 
50s and low 60s as light SW winds continue for most; winds to 15 kt 
will be possible through tonight across the Cape and Islands.

A warm front will push through southern New England Wednesday 
evening/night and showers and thunderstorms will likely accompany 
it. With regards to severity, not seeing much that would scream a 
severe weather threat with these possible storms. CSU ML guidance 
has about a 5-15 percent chance for severe winds in western MA and 
CT, along with part of central MA for Wednesday. Winds also shift 
more southerly going into Wednesday afternoon/evening, helping bring 
in more moisture from the south. PWATs may approach 2.0", and NAEFS 
guidance indicates that values Wednesday into Thursday morning may 
be around 2-3 standard deviations above normal. Details regarding 
the coverage of these showers and storms still need to be ironed 
out, but the latest guidance is favoring the heavier rainfall 
remaining to our north and south. With the moist airmass overhead, 
some spots with locally heavier rainfall can't be ruled out, but 
much can still change between now and when this front comes through. 
Rainfall amounts at this time may only reach around 0.10-0.20". Hot 
and humid conditions will be left in the wake of this warm frontal 
passage.

KEY MESSAGE 2...Diurnal showers and thunderstorms possible Wednesday 
through  Friday. Above normal temperatures peaking Thursday into 
Friday.

High pressure towards the southeast USA will push heat and humidity 
into southern New England later this week. Will likely need to 
consider heat headlines with later forecasts. Uncertainty remains 
for how quickly and how far west a backdoor cold front can make it 
Friday. This would have implications for heat headlines across 
eastern MA as well as RI. Should this front be delayed from its 
current timing, then more of southern New England would be at risk 
for headlines using the lower 2-day threshold.

Portions of the CT River Valley in MA and CT could see heat index 
values around 100F, while more of our region should be well into the 
90s both Thursday and Friday. Coastal areas of MA and RI are 
expected to be cooler Friday, but the timing still needs to be 
ironed out.

The increased heat and humidity will also set the stage for possible 
showers and thunderstorms later this week. There is not much concern 
for the threat of widespread severe thunderstorms at this time due 
to the lack of wind shear and weak forcing mechanisms. The western 
half of southern New England would have the higher risk, which is 
not unusual for this time of year.

KEY MESSAGE 3...Warm conditions with lower humidity throughout this 
weekend. Uncertainty remains high regarding potential rain showers 
for Saturday, and again early next week.

Anticipating the passage of a couple fronts Saturday and Sunday. The 
main impact will be lower humidity, with Sunday anticipated the 
drier of the two. Lingering showers possible Saturday, but plenty of 
dry hours too. Some guidance members indicated a weak low pressure 
passing by towards the south coast of New England sometime Monday 
into Tuesday. Kept a mention of showers in the forecast, but 
confidence in these details is low.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

18z TAF Update...High confidence.

VFR conditions continue into much of Wednesday. Some MVFR to 
localized IFR conditions may overspread parts of the region from
southwest to northeast by early evening Wednesday along with a 
few showers. Showers become more likely Wednesday night, but
coverage is still relatively uncertain.

Gusts will diminish this evening, but may linger a bit longer 
near the upper Cape/Buzzards Bay area. For Wednesday, gusts to
around 20 kt may make a return by the mid/late morning hours. SW
winds will persist through tonight and into Wednesday before
shifting more S Wednesday night in the wake of a passing warm
front.

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday through Thursday Night: Mainly VFR, with local MVFR
possible. Chance SHRA, slight chance TSRA.

Friday: Mainly VFR, with local MVFR possible. Chance SHRA,
chance TSRA.

Friday Night: VFR. Chance SHRA, slight chance TSRA.

Saturday: VFR. Slight chance SHRA.

Saturday Night through Sunday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Wednesday Night...High confidence.

Small Craft Advisories continue over the nearshore southern waters 
with the elevated SW winds continuing into this evening. After that, 
winds will be sustained at or below 15 kt with only occasional gusts 
to 25 kt expected more towards Nantucket and the outer waters near 
it. Winds shift more SW then SSW Wednesday afternoon, sustained at 
around 15-20 kt with gusts remaining just below Small Craft 
criteria. Seas generally 2-4 ft through Wednesday night, though the 
southern outer waters may start to creep to 5 ft heading into 
Thursday morning.

Outlook /Thursday through Sunday/...

Thursday: Winds less than 25 kt. Local rough seas. Chance of
rain showers, isolated thunderstorms. 

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers, isolated thunderstorms. 

Friday: Winds less than 25 kt. Seas locally approaching 5 ft. 

Friday Night through Saturday: Winds less than 25 kt. Slight
chance of rain showers. 

Saturday Night through Sunday: Winds less than 25 kt. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 PM EDT this evening for 
     ANZ231>236.

&&

$$

DISCUSSION...Belk/Hrencecin
AVIATION...Belk/Hrencecin
MARINE...Belk/Hrencecin