Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: Light rain, Mostly cloudy
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 191905
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
305 PM EDT Fri Jun 19 2026

.WHAT HAS CHANGED...
Issued small craft advisories for all waters and extended them 
through Saturday early evening, as west winds will remain breezy. 
Increased wind gusts with a risk for scattered afternoon showers on 
Saturday.

&&

.KEY MESSAGES...

- Cooler with westerly breezes this weekend. Risk of scattered
  afternoon showers thru sundown, then scattered showers and a
  rumble of thunder on Sunday afternoon, but risk for severe
  weather is very low. 

- Periods of heavy rain possible Monday into early Tuesday. 
  Drier air with seasonable temperatures expected midweek.


&&

.DISCUSSION...
KEY MESSAGE 1...Cooler with westerly breezes this weekend. Risk of 
scattered afternoon showers thru sundown, then scattered showers and 
a rumble of thunder on Sunday afternoon, but risk for severe 
weather is very low. 

Cyclonic mid-level flow governs our weather in Southern New England 
this weekend. In that broader cyclonic flow aloft, a stronger closed 
low over Quebec is expected to dig south-southeast into Maine and 
the Gulf of Maine Saturday afternoon. Another weaker disturbance 
moves through the flow on Sunday. Each of these disturbances will be 
responsible for diurnally-driven scattered shower activity, with a 
little more (if still weak) instability leading to scattered diurnal 
showers with a risk for a thunderstorm or two. Highs should be in 
the 70s to lower 80s on Saturday, and in the low 80s on Sunday, but 
both days feature comfortable humidities. 

Westerly winds have been gusting to 25-35 mph this afternoon with 
the cold pool of air aloft helping to drive good mixing. Most models 
show the low-level jet increasing post-sundown, but by that point, 
more limited mixing as temperatures fall should temper the gusts to 
around 20-25 mph. Gust speeds are expected to be similar by mid-
morning Saturday too - around 25 to 30 mph - but the directions are 
more from the NW than today. 

Shallow, weak instability is forecast for Saturday, and with a litle 
better dynamics coming down from the upper trough on Saturday, best 
chance for afternoon scattered showers is from Springfield to 
Providence north and east. Not everyone sees these showers, but 
there will be some to dodge during the afternoon to early evening 
hours. With temps running a few degrees warmer on Sunday, there's a 
better risk for pop-up showers with a garden-variety thunderstorm or 
two possible during the daytime hours. 

KEY MESSAGE 2...Periods of heavy rain possible Monday into 
early Tuesday. Drier air with seasonable temperatures expected 
midweek.

A 500mb closed off low will slowly rotate through the upper Great 
Lakes region with a weak shortwave trough moving into the Northeast 
on Monday. At the surface, a low pressure system will track across 
Southern New England, bringing significant moisture to the region. 
Models continue to show precipitable water values of 1.50 to 2.00 
inches, which would be well above climatological normals for mid 
June. Widespread precipitation is likely mainly Monday into Monday 
night with pockets of heavy rainfall possible. The latest National 
Blend of Models run continues to show high probabilities (around 80% 
chance) of greater than 1 inch of rainfall areawide and around 50% 
chance of greater than 2 inches.

Behind the system, high pressure and northwest flow will bring 
rapidly drying conditions during the day on Tuesday. Temperatures 
are then expected to be pleasant midweek with seasonable highs in 
the upper 70s to low 80s and only isolated rain chances possible 
at the end of the period on Thursday.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

18z TAF Update: 

Through Tonight: High confidence. 

VFR. A spot shower possible toward BDL around 23-01z but 
confidence is too low for a mention in TAF. W wind gusts 25-30 
kt, and though they should begin to ease some after sundown, 
still could see gusts in the 20-25 kt range overnight as the 
low-level jet increases. 

Saturday: High confidence. 

VFR; some risk for diurnal SHRA with brief MVFR-VFR visbys 
after 17z mainly from BDL to PVD north and east through sundown 
and indicated with PROB30s. WNW winds again gusting 25-28 kt by 
mid-morning Saturday, then easing into sundown.

Saturday Night: High confidence.

VFR, any showers diminish post-sundown. WNW winds decrease to 
5-10 kt.

KBOS Terminal...High confidence in TAF. Westerly gusts 25-30 kt
continue through sundown, but will still be clocking in around
20-25 kt overnight.
 
KBDL Terminal...High confidence in TAF.

Outlook /Saturday Night through Wednesday/...

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

Sunday Night: VFR. 

Monday: Mainly VFR, with local IFR possible. Breezy. SHRA,
chance TSRA.

Monday Night: Mainly MVFR, with local IFR possible. Breezy.
SHRA, slight chance TSRA.

Tuesday: VFR. Breezy. Chance SHRA.

Tuesday Night through Wednesday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels...

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

Have issued SCAs on all waters and extended them through Saturday 
early evening, as westerly winds will be gusting to around 25-30 kt 
through Saturday. There may be some lull in the gusts overnight but 
would be short-lived and/or resume early Saturday morning. Seas in 
the 4-6 ft range, with 3-5 ft nearshore through Saturday. Risk for 
scattered showers during Saturday afternoon. 

Winds and seas should trend below SCA criterion Saturday night 
through Sunday, with gusts to 20 kt.

Outlook /Saturday Night through Wednesday/...

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

Sunday Night: Winds less than 25 kt. 

Monday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Seas locally approaching 5 ft. Chance of rain
showers. 

Monday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 10 ft. Rain showers, chance
of thunderstorms. 

Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Areas of rough seas. Chance of rain showers. 

Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 9 PM EDT Saturday for ANZ230>235-
     237-251.
     Small Craft Advisory until 1 AM EDT Sunday for ANZ250-254>256.

&&

$$

DISCUSSION...Loconto/Birchfield
AVIATION...Loconto/Birchfield 
MARINE...Loconto/Birchfield