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 300636
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
236 AM EDT Thu Apr 30 2026

.WHAT HAS CHANGED...

Extended the Small Craft Advisory for the outer waters through 
8pm Friday.

&&

.KEY MESSAGES...

- Steady rain continues through much of the day giving way to a 
clearing trend from west to east this afternoon. 

- Cooler and mainly dry this weekend with a coastal storm passing 
well offshore.

- Warmer albeit unsettled conditions return next week.

&&

.DISCUSSION...

KEY MESSAGE 1... Steady rain continues through much of the day 
giving way to a clearing trend from west to east this afternoon. 

Broad lift from approaching low pressure brings a shield of rain to 
southern New England through much of the day today. Main area of low 
pressure tracks through the St. Lawrence Valley. Weak secondary low 
tracking from mid Atlantic will help enhance showers mainly across 
eastern Mass and the Islands this afternoon into the early evening. 
High-res guidance still shows some elevated instability developing 
by the afternoon as the dry slot works its way overhead. Best chance 
for any isolated thunder will be on the edge of the dry slot
focused near Cape Cod and Islands, but moreso offshore. Solid 
rainfall event on the order of around 0.5" for most, but still 
much needed given recent rainfall departures.

KEY MESSAGE 2...Cooler and mainly dry this weekend with a coastal 
storm passing well offshore.

Amplified pattern over the weekend should feature a building ridge 
of high pressure over central Canada which traps a closed 532 
decimeter upper low over southern Ontario. There are still slight 
differences among global guidance in the exact location and strength 
of the ridge over Canada. The ECMWF shows a more southern solution 
and thus a bit more in the way of shower activity later Saturday 
afternoon. On the whole, southern New England should be far 
enough removed from coldest air aloft to keep us mostly dry, 
especially given W/NW flow, but pattern certainly favors diurnal
clouds and perhaps a few afternoon sprinkles over weekend.

Guidance continues to show a fairly weak low that may bring a few 
showers or perhaps a period of light rain to the southern coast and 
the Cape/Islands Saturday night into Sunday morning. Recent trends 
still paint a weak unamplified picture with the majority of the EPS 
and GEFS ensembles showing a further offshore track. 

KEY MESSAGE 3... Warmer albeit unsettled conditions return next 
week.

Pattern relaxes a bit early next week as closed low lifts farther 
north, but we remain under broad cyclonic flow aloft. Eventually 
longer range guidance shows closed low setting up near upper Great 
Lakes, putting us in SW flow aloft. This could end up bringing more 
moisture and warmer air into region by Tuesday/Wednesday as weak 
front approaches resulting in scattered showers. Ensemble guidance 
shows 850 mb temp anomalies climbing to +10F above climo Tuesday and 
Wednesday of next week.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

06z TAF Update: Moderate confidence due to timing of flight 
categories.

Widespread -SHRA thru 14z with IFR ceilings/visibilities. 
Showers come to an end around midday today with gradual 
improvement to MVFR ceilings, and possibly VFR later in day with
the exception of Cape Cod and Islands. 

Quick improvements to VFR from W to E tonight with slower
improvements for the Cape and Islands. 

KBOS Terminal...Moderate confidence. Reduced confidence in the
end time of IFR/LIFR this afternoon.

KBDL Terminal...High confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: VFR. 

Saturday through Saturday Night: VFR. Chance RA.

Sunday: VFR. Breezy. Slight chance RA.

Sunday Night: VFR. 

Monday: VFR. Breezy. 

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence through the end of the week.

Pressure gradient between slow-moving low pressure SE of the 40/70 
benchmark and high pressure over the Canadian Maritimes keeps E/NE 
winds in play through the end of the week. 

Main issue will be the long fetch of NE winds resulting in rough 
seas of 5 to 8 feet on outer waters through Thu where SCA remains 
posted. Areas of fog will persist through tonight along with 
showers.

Outlook /Friday Night through Monday/...

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

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

Saturday Night through Sunday: Winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain. 

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

Monday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Seas up to 5 ft. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Friday for ANZ250.
     Small Craft Advisory until 8 PM EDT Friday for ANZ254>256.

&&

$$

DISCUSSION...FT
AVIATION...FT
MARINE...FT