Old Res Weather

Lexington, Massachusetts, USA

35°F

2/16/2025 7:17pm

Lexington Conditions: 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: 10 miles
Rain Today: 0.01 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 071103
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
603 AM EST Sat Mar 7 2026

.WHAT HAS CHANGED...
No significant changes. Becoming more confident in springtime
warmth, especially Tuesday, along with the potential for minor 
river flooding next week.

&&

.KEY MESSAGES...

- Black ice possible early this morning, otherwise a significant 
  warming trend this weekend with the potential to reach 60+ 
  in spots by Sun. Dry weather outside a brief round of showers & 
  perhaps a rumble of thunder late tonight into very early Sun am.

- Springtime warmth next week may lead to minor river flooding
  from melting snow, but we also need to watch a backdoor front
  to the north, which could bring cooler temperatures Wed-Thu.

&&

.DISCUSSION...
KEY MESSAGE 1...Black ice possible early this morning, 
otherwise a significant warming trend this weekend with the 
potential to reach 60+ in spots by Sun. Dry weather outside a 
brief round of showers & perhaps a rumble of thunder late 
tonight into very early Sun am.

Areas of drizzle and spotty freezing drizzle mainly in the high 
terrain will dissipate by early mid-morning. Until that time...black 
ice will be a concern especially in the high terrain but can not be 
ruled out in some lower elevations given temps near freezing. 
Therefore...will continue the special weather statement until mid-
morning. 

Strengthening 850 MB LLJ will allow the surface winds to shift to a 
SSW direction by early-mid morning. However...model soundings show 
an abundance of low level moisture/saturation from the surface to 
925 mb. This will result in low clouds hanging tough today. 
Nonetheless...surface winds becoming SSW will allow afternoon highs 
to reach the upper 40s to near 50 this afternoon. We will need to 
watch for advection fog some of which may become locally dense today 
into tonight near the south coast, Cape & Islands. This a result of 
southerly advection of high dewpoint air over the very cold ocean. 
Temps will only drop into the 40s tonight and may actually rise 
toward daybreak. Dewpoints will also be rising into the 40s...so 
considerable snow melt will occur over the next 24 hours. 

A weakening complex of showers and t-storms will approach the region 
from the west very late tonight into early Sat morning. A round of 
brief scattered showers and perhaps even a rumble of thunder will be 
possible. Otherwise...low clouds and fog should eventually scour out 
on Sunday except perhaps for areas near the south coast. 925T in the 
+7C to +9C range indicate good potential for highs to approach or 
break 60 degrees on Sunday...at least away from the south coast. 
The remaining snowpack will quickly be melting away. 

KEY MESSAGE 2...Springtime warmth next week may lead to minor river 
flooding from melting snow, but we also need to watch a backdoor 
front to the north, which could bring cooler temperatures Wed-Thu.

A very warm stretch coming up compared to what we've experienced 
recently. For context, normal high temperatures for early March are 
in the low to mid 40s. This stretch of warmth, peaking on Tuesday, 
looks to reach 20 to 25 degrees above normal values, well into the 
60s or even 70 in spots. EPS ensemble guidance continues to show 30-
50% chance of reaching 70F though the GEFS is less enthused. 
Regardless, warm w/SW flow around an Atlantic high will bring well 
above average temperatures through mid week, though those along the 
immediate south coast will see much cooler temps thanks to air 
off the cold ocean. The increasing warmth raises concerns for 
rises on rivers and streams as we quickly lose our snowpack. 
Ensemble guidance continues to indicate a 20-40% probability of 
minor river flooding as early as Mon-Tue. As we get closer and 
have more high resolution guidance we'll also have to nail down 
how far south a backdoor cold front may sink late Tuesday into 
Wednesday which would put a damper on warm temperatures for at 
least northeast MA if not areas further south and west. The next
shortwave disturbance and cold front arrives by the end of the 
week bringing cooler and wetter weather.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

12z TAF Update...

Today...High confidence.

IFR/LIFR conditions dominate today and tonight. Lingering -DZ and 
localized -FZDZ which was mainly in the high terrain will come to an 
end by mid morning. Otherwise...surface winds shift to the SSW at 8-
15 knots with some 20+ knot gusts today. This may allow cigs/vsbys to 
improve very slightly to IFR levels in some locations away from the 
south coast later today and into tonight. However...LIFR conditions 
will be favored near the south coast where advection fog perhaps 
even dense at times will impact areas near the south coast, Cape and 
Islands. 

Tonight...High confidence. 

A band of of showers will approach western MA/CT after 03z/04z 
tonight and may reach the coastal plain 06z/07z. While the showers 
will be undergoing a weakening trend...they still may survive in 
some form and reach the coast. Perhaps even an isolated rumble of 
thunder. S-SW winds will gust between 15 and 25 knots. We also
will have LLWS in the TAFS given an 850 mb southwest LLJ on the
order of 55-70 knots.

Sunday...High confidence in trends with moderate confidence
in timing. 

Gradual improvement will occur on Sunday with many locations 
eventually improving to VFR by mid afternoon...except for areas near 
the south coast, Cape & Islands where low clouds and fog may 
persist. SW winds should shift to the W at 10 to 15 knots. 

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday: Mainly VFR, with local IFR possible. Breezy. Slight
chance RA, patchy BR.

Sunday Night: VFR. 

Monday: VFR. Breezy. 

Monday Night through Tuesday: VFR. 

Tuesday Night: Slight chance RA.

Wednesday: Breezy. Chance RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Sunday...High confidence. 

Lingering small craft swell will require headlines across our outer-
waters through the weekend. In addition...shortwave/warm front will 
result in a period of southwest wind gusts of 20 to 30 knots tonight 
into Sunday morning for most of our waters. Therefore...we have 
additional small craft headlines for all our open waters over this 
time.

Lastly...areas of fog and poor visibility will be an issue for 
mariners the entire weekend especially near the south coast.

Outlook /Sunday through Wednesday/...

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Areas of rough seas. Chance of rain, patchy fog.
Areas of visibility 1 nm or less.

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

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

Tuesday through Tuesday Night: Winds less than 25 kt. 

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of seas approaching 5 ft. Chance of rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 6 PM this evening to noon EST Sunday 
     for ANZ231>235-237.
     Small Craft Advisory until 7 PM EST Sunday for ANZ250-251-
     254>256.

&&

$$

DISCUSSION...Frank/BW
AVIATION...Frank/BW
MARINE...Frank/BW