Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Mist, 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: 2 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 231931
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
331 PM EDT Sun Aug 23 2026

.WHAT HAS CHANGED...

A high risk for rip current statement has been issued for Nantucket 
on Monday. 

&&

.KEY MESSAGES...

- Outside a few showers/isolated t-storm risk into mid evening
  with the focus across the interior especially near and west of
  the CT River Valley. Areas of fog develop overnight which may
  become locally dense in spots. 

- Drier with a return to seasonable temperatures this week. Rain
  chances return Thursday/Friday.

&&

.DISCUSSION...

KEY MESSAGE 1...Outside a few showers/isolated t-storm risk into mid 
evening with the focus across the interior especially near and west 
of the CT River Valley. Areas of fog develop overnight which may 
become locally dense in spots. 

The main cluster of showers that resulted in brief heavy rain along 
with a rumble or two of thunder has exited the eastern Ma coast 
earlier this afternoon. Behind this activity some subsidence and 
drier mid level air was allowing the lower clouds to begin to mix 
out from southwest to northeast. We will see a late rise in temps 
through early evening well into the 70s to perhaps near 80 in the CT 
River Valley as some peeks of sun try to develop. This will result 
in some modest instability developing with ML Capes approaching 1000 
J/KG across parts of the interior. However...subsidence behind the 
earlier shortwave coupled with the main forcing well to our west 
will limit the additional risk. Nonetheless...a few showers and 
perhaps an isolated t-storm or two will be possible into mid-
evening. The main focus for this activity will be across the 
interior and especially near and west of the CT River Valley closer 
to the upper level shortwave.

Otherwise...the main story later tonight will be for the development 
of fog some of which may become locally dense. Winds become 
light/calm overnight coupled with partial clearing, wet ground and 
dewpoints remaining in the 60s will set the stage for fog 
development. Some of the fog may become locally dense too. Low 
temperatures overnight will drop into the middle to upper 50s in the 
outlying locations...to the middle 60s in the urban heat islands of 
downtown Boston/Providence. 

KEY MESSAGE 2...Drier with a return to seasonable temperatures this 
week. Rain chances return Thursday/Friday.

A post-frontal air mass ushers in drier conditions and warmer 
temperatures on westerly winds this week. As skies gradually clear 
from the dreary weekend, dewpoints will begin to drop slightly... 
into the upper 50s as opposed to the low to mid 60s we've been 
seeing. High pressure begins to slowly build Tuesday into Wednesday, 
prolonging the clear skies, drier weather, and warmer temperatures 
through the middle of the week. Expecting temperatures to return to 
seasonable, in the upper 70s to low 80s, and feel less humid 
thanks to the lower dewpoints through the end of the week.

Chances for rain showers return Thursday and Friday as a low 
pressure system develops over the Great Lakes and meanders east 
through southern Ontario. Some uncertainty remains regarding the 
onset of the showers as there's little consistency in the global 
ensembles on the actual placement of the low as it tracks through 
Canada; however, confidence has ticked up slightly in a later show 
of showers Thursday evening into the overnight period compared to 
yesterday's model runs.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...

Forecaster Confidence Levels...

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

18z TAF Update...

This afternoon through tonight...Moderate confidence in trends
but lower confidence in specific timing. 

The main cluster of showers and an occasional rumble of thunder
or two will be exiting eastern MA by mid afternoon. 
Otherwise...a few additional showers and perhaps an isolated 
t-storm will be possible into mid evening with the focus across
interior southern New England and particularly areas near and 
west of the CT River Valley.

IFR/LIFR conditions will be improving to mainly MVFR-VFR by 
early-mid evening in most locations although the process will be
slowest across the Cape/Islands. However...a wet ground, light 
winds and dewpoints still in the 60s will likely result in areas
of fog developing in the typically prone locations. Some of 
that fog may become locally dense overnight...while areas like 
KBOS end up going VFR. So a wide variety of conditions possible 
toward daybreak. Winds become calm/light SW tonight. 

Monday and Monday night...High confidence. 

Any leftover ground fog quickly burns off after sunrise Mon.
Otherwise...VFR with SW winds of 7-13 knots. Mainly VFR 
conditions continue Mon night outside of any localized patches 
of ground fog that develop in those typically prone locations. 
Winds become calm/light SW Mon night. 

KBOS Terminal...Moderate confidence in trends but lower
confidence in specific timing. 

KBDL Terminal...Moderate confidence in trends but lower
confidence in specific timing.

Outlook /Tuesday through Friday/...

Tuesday: VFR. Breezy. 

Tuesday Night through Wednesday Night: VFR. 

Thursday: VFR. Breezy. Chance SHRA, slight chance TSRA.

Thursday Night through Friday: 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 Monday night...High confidence.

The pressure gradient will generally remain weak enough to keep 
winds/seas below small craft advisory through Monday night. 
However...nearshore SW winds may gust into the lower 20 knots late 
Monday result in some decent chop for recreational boaters. 

Outlook /Tuesday through Friday/...

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

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

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

Wednesday Night through Thursday: Winds less than 25 kt. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents from Monday morning through Monday 
     afternoon for MAZ024.
RI...None.
MARINE...None.

&&

$$

DISCUSSION...Frank/McMinn
AVIATION...Frank/McMinn
MARINE...Frank/McMinn