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 111756
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
156 PM EDT Thu Jun 11 2026

.WHAT HAS CHANGED...
Forecast remains on track at this time.

&&

.KEY MESSAGES...

- Heat Advisories advisories remain in effect for northern CT 
  and much of interior MA from noon today to 8pm Friday.

- A few scattered strong to severe thunderstorms are possible 
  Thursday and Friday. 

- Above normal temperatures continue into early next week, but 
  humidity will be on the decrease. Weekend looking mostly dry, 
  while uncertainty remains high regarding potential for rain 
  showers early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Heat Advisories advisories remain in effect for
northern CT and much of interior MA from noon today to 8pm 
Friday.

Increasing heat and humidity pose a risk today and Friday with 
the arrival of the warmest airmass of the season. Prolonged 
southwesterly flow will bring a surge of very hot and humid air,
especially as 925mb temperatures increase to +27C Thursday and 
up to +30C Friday. Surface dewpoints are already in the low 60s 
just after 2AM and will only continue to climb throughout the 
day, likely topping out at or near 70, especially across 
interior MA and northern CT. These high dewpoints combined with 
temperatures climbing into the low to mid 90s will lead to heat 
index values approaching 100F today and likely above 100F Friday
across the CT River Valley. As such, Heat Advisories remain in 
effect for these areas through 8pm Friday.

Temperatures across RI and eastern MA likely remain in the 
upper 80s to low 90s across both days. Dewpoints surging to at 
or near 70 across most of southern New England both today and 
Friday will lead to heat indicies in the low 90s, especially 
away from the coastal plain. A backdoor cold front is also 
expected to drop into eastern MA sometime on Friday. Onshore 
flow will provide some relief from the heat Friday... likely 
leading to temperatures along the immediate coast topping out in
the low 80 with heat indicies in the mid to upper 80s. Some 
uncertainty still remains how far inland the front will push, 
but currently thinking it'll fall short of reaching ORH. 
Regardless, widespread moderate heat impacts are expected across
the region, with pockets of major heat impacts possible in the 
CT River Valley, both today and Friday, leading to an increased 
risk of heat-related illness for anyone spending extended time 
outdoors without adequate hydration or access to cooling.

KEY MESSAGE 2...A few scattered strong to severe thunderstorms 
are possible Thursday and Friday. 

The increased heat and humidity combined with a series of weak 
upper- level disturbances continue to be the catalyst for 
showers and thunderstorms later today and again Friday. While 
confidence has waned somewhat, the potential for some severe 
storms across western CT this evening remain. CSU ML 
probabilities continue to show 15-30 percent for severe wind 
potential, and the latest guidance shows CAPE values upwards of 
1500 J/kg with pockets of up to 2200 J/kg possible across far 
western CT... however, those higher values are likely to quickly
decay as they push east, which would lead to short- level 
cells. Latest CAMs continue to show 0-6km Bulk Shear values 
struggling to reach 20 kts, with highest values concentrated 
across western and southern CT. Regardless, any storms that do 
form will quickly tap into the unstable airmass, with the 
primary threat continuing to be damaging winds.

Friday looks to be very similar, with the exception that CSU ML
probabilities have a narrow corridor in western CT favoring a 
30 to 45 percent chance for severe winds. Some model sounding 
are indicating significantly higher DCAPE values Friday evening 
compared to this evening, which would support a chance for 
higher thunderstorm driven winds. Uncertainty remains Friday 
regarding how widespread storm coverage could be.

KEY MESSAGE 3...Above normal temperatures continue into early 
next week, but humidity will be on the decrease. Weekend looking
mostly dry, while uncertainty remains high regarding potential 
for rain showers early next week.

A weak high pressure sandwiched between two fronts should 
dominate our weather for most of this weekend, bringing lowering
dewpoints and decreased humidity. While it will still be plenty
warm for most of southern New England, peak heat index values 
should remain mainly in the 80s, with a few locations reaching 
the lower 90s.

Still quite a bit of uncertainty with the details of the 
forecast early next week. The latest guidance stalls yet another
front towards the south coast of New England as a weak low 
pressure develops towards NJ sometime Monday night into Tuesday.
The forcing looks rather weak, but cannot completely dismiss 
the idea of scattered showers in our area at times. A subtle 
shift of even just 20 miles to the south, and the forecast could
be largely dry. Changes with later forecasts are expected.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

This afternoon...Moderate confidence. 

VFR except for ACK where IFR cigs/vsbs persist. There is a risk
for thunderstorms between 19Z and 02z, but the risk is highest 
at BDL. There is a chance for -SHRA/-TSRA at the other 
terminals, but confidence is lower. 

Tonight...Moderate confidence.

-SHRA/-TSRA tapers off by 03-04Z. Mainly VFR, with some MVFR/IFR
 vsbys developing in patchy fog mainly over Cape/islands. Light
 and variable winds.

Friday...Moderate confidence.

VFR. Light onshore winds developing. A few rounds of TSRA
developing, first in the 18-00Z time period over eastern MA and
RI terminals, then again a broken line of storms is possible in
the 23z-06z period. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...Moderate Confidence in TAF. Risk for -TSRA this
afternoon/evening between 23Z and 02Z but may depend on if the
seabreeze makes it into the terminal which is becoming more
uncertain the later into the day we get. 

Friday night...High confidence in TAF. 

SHRA/TSRA exiting by 06z. VFR. NW winds 5-10 kts. 

Outlook /Saturday through Tuesday/...

Saturday: VFR. Breezy. 

Saturday Night: VFR. 

Sunday: VFR. Breezy. 

Sunday Night: VFR. Breezy. Chance SHRA, slight chance TSRA.

Monday: VFR. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Friday...High confidence.

Seas 2-4 feet for the majority of the waters except 3-5 feet
across the southern outer waters tonight. SW winds increase to 
15-25 kt with gusts as high as 30 kts. Areas of showers and 
perhaps a thunderstorm or two through Thursday morning. SCA 
conditions continue for the southern waters Thursday before 
gradually subsiding by the late evening.

Outlook /Friday Night through Tuesday/...

Friday Night: Winds less than 25 kt. Chance of rain showers. 

Saturday through Sunday: Winds less than 25 kt. 

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Rain showers likely, slight chance of thunderstorms. 

Monday: Winds less than 25 kt. Chance of rain showers, slight
chance of thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Friday for CTZ002>004.
MA...Heat Advisory until 8 PM EDT Friday for MAZ002>006-008>014-017-
     018-026.
     Air Quality Alert until 11 PM EDT this evening for MAZ013-
     016>024.
RI...Heat Advisory until 8 PM EDT Friday for RIZ001>004.
     Air Quality Alert until 11 PM EDT this evening for RIZ001>008.
MARINE...Small Craft Advisory until 8 PM EDT this evening for 
     ANZ254>256.

&&

$$

DISCUSSION...McMinn
AVIATION...BW
MARINE...McMinn