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 061810
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
210 PM EDT Sat Jun 6 2026

.WHAT HAS CHANGED...

No significant changes to the current forecast. 

&&

.KEY MESSAGES...

- A cluster of showers & thunderstorms works across the region
  between 5 and 11 pm this evening. A few storms may become 
  severe and produce damaging wind gusts, dangerous cloud to 
  ground lightning and brief torrential rainfall.
 
- Scattered showers and perhaps a few embedded t-storms develop 
  Sunday afternoon/early evening with the focus across eastern 
  New England Drier and much cooler weather follows Sunday night. 

- Seasonable temperatures Monday, followed by another stretch of
  summerlike heat and building humidity. No notable storms next
  week, though a front may bring a period of showers and 
  thunderstorms mid to late week.

&&

.DISCUSSION...

KEY MESSAGE 1...A cluster of showers & thunderstorms works across 
the region between 5 and 11 pm this evening. A few storms may become 
severe and produce damaging wind gusts, dangerous cloud to ground 
lightning, and brief torrential rainfall.

Breaks in the mid-high level cloudiness has allowed for partial 
sunshine to develop. This will continue to push highs well into the 
80s to near 90 in many locations by late afternoon. Low level 
moisture is limited and will probably keep surface Capes on the 
order 1000 to 1500 J/KG. This is on the marginal side...But bulk 
effective shear increasing to between 30 and 40 knots will try to 
offset that.  

Given the above parameters...we expect a cluster of showers and 
thunderstorms to develop and enter western MA and CT after 5-6 pm. 
This potential will likely not reach the BOS-PVD corridor until 
after 7-8 pm. A few of the storms may become severe and produce 
damaging wind gusts. While this potential exists across most of our 
region...the greatest risk will be across interior MA & CT given 
better instability/more favorable timing. 

We will have to see if the bulk effective shear is enough to 
overcome the limited instability...but mid level lapse rates are 
decent for our standards on the order of 6/6.5 C/KM. Main severe 
weather risk will be localized damaging wind gusts given decent T/Td 
spread. Much of the machine learning guidance supports this as well 
indicating localized damaging wind gusts the main severe weather 
threat. They also indicating this potential across most of our 
region...But show the greatest threat across interior MA & CT. 

So in a nutshell...a few severe thunderstorms possible between 5 and 
11 pm this evening. Greatest risk will be after 5-6 pm across 
interior southern New England...But can not rule out the risk 
approaching the I-95 corridor after 7-8 pm this evening. In 
addition...brief heavy rain and dangerous cloud to ground lightning 
are possible too. Bulk of any activity will probably exit the region 
by midnight followed by mainly dry weather. It will remain mild and 
a bit muggy compared to what we have experienced lately...low temps 
will only drop into the 60s. 

KEY MESSAGE 2...Scattered showers and perhaps a few embedded t-
storms develop Sunday afternoon/early evening with the focus across 
eastern New England.

Dry weather is on tap Sunday morning...but a strong shortwave/cold 
pool aloft and associated cold front will be dropping south Sunday 
afternoon. This will combined with diurnal heating and trigger the 
development of afternoon scattered showers and a perhaps a few 
embedded thunderstorms. While a few showers will be possible across 
the entire region...areal coverage should be the greatest in 
central/eastern MA and RI given better instability. Not expecting 
severe weather...But a few thunderstorms possible especially towards 
the I-95 corridor. Given 500T dropping to between -14C to -16C we 
can not rule out some small hail if a thunderstorm two is able to 
develop. Highs will mainly be in the upper 70s to the lower 80s.

Showers may linger into the evening across parts of eastern MA/RI 
into the evening. Otherwise...drier and much cooler air works into 
the region overnight. Lows by daybreak Monday will be in the middle 
to upper 40s in the outlying locations and lower to middle 50s in 
the urban centers. 

KEY MESSAGE 3...Seasonable temperatures Monday, followed by 
another stretch of summerlike heat and building humidity. No 
notable storms next week, though a front may bring a period of 
showers and thunderstorms mid to late week.

Sundays mid-level trough exits east of New England by early Monday 
morning as an amplified ridge shifts toward the eastern third of the 
CONUS. The trough eventually evolves into a cutoff mid-level low 
over the Canadian Maritimes, helping to slow eastward progression of 
the ridge and supporting another stretch of summerlike temperatures 
across southern New England. Monday will likely be the coolest day 
of next week due to north-northeast flow aloft draining a cooler 
airmass southward into the region. Forecast soundings Monday 
afternoon depict a well-mixed atmosphere with the boundary layer 
extending to around 850 mb and temperatures at that level ranging 
from +8C to +12C. Naturally, the farther east, the cooler 
temperatures will be, with Cape Cod, the Islands, Boston, and the 
eastern coastal plain largely remaining in the 70s, while the 
Connecticut River Valley reaches the lower to middle 80s. Through 
much of next week, an anomalous ridge extending north toward Hudson 
Bay in Canada favors mainly dry and increasingly hot conditions. 850 
mb temperatures rise to around +15C Tuesday, then increase to around 
+18C Wednesday through Friday. This should support highs in the 
middle 80s to near 90 Tuesday, followed by upper 80s to lower 90s 
through much of the remainder of the week. The first half of next 
week should feature relatively comfortable dewpoints in the 50s. 
However, by late week, dewpoints rise into the 60s, leading to a 
more humid airmass. While outside the forecast period, there is a 
signal for heat to continue into next weekend, reflected in CPC 
outlooks depicting a Slight Risk (20 to 40% probability) for extreme 
heat across portions of the Northeast. In terms of precipitation, 
there does not appear to be anything appreciable on the horizon 
through much of next week. However, a frontal passage late in the 
week may bring a period of showers and thunderstorms as heat and 
humidity continue to build.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

Forecaster Confidence Levels...

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

18z TAF Update...

Through tonight...Moderate confidence.

The main issue will be for scattered showers and thunderstorms that 
will likely enter western MA/CT after 21z/22z and approach the 
coastal plain after 00z/01z. Brief MVFR/IFR conditions are possible 
with this activity along with localized strong wind gusts. Greatest 
risk for this is across interior southern New England...But there is 
the risk for this right to the I-95 corridor. The bulk of this 
activity should exit the southeast New England coast near 05z-06z. 
Outside this activity...VFR conditions will dominate tonight. The 
exception might be towards the Cape/Islands...where low clouds and 
fog patches may develop overnight with the best chance across 
Nantucket.

Sunday and Sunday night...High confidence.

Any lower clouds/fog patches that form towards the Cape/Islands 
should burn off Sunday morning. Otherwise...VFR conditions dominate 
outside of scattered showers that are expected to develop Sunday 
afternoon. A few embedded t-storms are possible too...but areal 
coverage and intensity is expected to be significantly less than 
this evening. Winds shift to the NW on Sun and gust to between 20 
and 25 knots. Winds then turn N Sun night at speeds of 5 to 15 knots 
but may temporarily decouple for a few hours in the typically prone 
locations late Sun night. 

KBOS Terminal...Moderate confidence in TAF. The main concern for 
thunderstorms crossing the terminal will be between 00z and 04z. 

KBDL Terminal...Moderate confidence in TAF. The main concern for 
thunderstorms crossing the terminal will be between 23z and 03z.

Outlook /Sunday Night through Thursday/...

Monday: VFR. Breezy. 

Monday Night: VFR. 

Tuesday: VFR. Breezy. 

Tuesday Night: VFR. 

Wednesday: VFR. Breezy. Slight chance SHRA.

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

Thursday: VFR. Chance SHRA, slight chance TSRA.

&&

.MARINE...

Forecaster Confidence Levels...

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

Tonight through Sunday night...High confidence.

We will continue marginal near shore small craft advisories into 
early-mid evening for marginal SW wind gusts near 25 knots. 
Otherwise...marginal 5 foot seas will flirt with the southern waters 
into Sunday while the rest of the region will be below small craft 
advisory criteria. However...a surge of northerly small craft wind 
gusts is expected Sunday night behind the cold front especially in 
our eastern waters. New small craft headlines will eventually be 
needed once most of current headlines expire. 

Lastly...a cluster of strong t-storms may approach our waters after 
7-8 pm this evening. They eventually should weaken and clear the 
southeast waters after 6z-7z or so. 

Outlook /Monday through Thursday/...

Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. 

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

Tuesday through Wednesday: Winds less than 25 kt. 

Wednesday Night: Winds less than 25 kt. Slight chance of rain
showers. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Air Quality Alert until 11 PM EDT this evening for MAZ013-
     016>024.
RI...Air Quality Alert until 11 PM EDT this evening for RIZ001>008.
MARINE...Small Craft Advisory until 9 PM EDT this evening for 
     ANZ231>235-237.
     Small Craft Advisory until 11 PM EDT this evening for ANZ250.
     Small Craft Advisory until 8 AM EDT Monday for ANZ254>256.

&&

$$

DISCUSSION...Frank/Dooley
AVIATION...Frank
MARINE...Frank/Dooley