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 110540
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
140 AM EDT Wed Mar 11 2026

.WHAT HAS CHANGED...
Small craft advisories hoisted on most waters for this evening into 
Thursday. River Flood Warning in effect for the Taunton River at 
Bridgewater due to snowmelt-induced river rise to minor flood stage. 
Cold front moving in Thurs has slowed down and could allow for hit 
or miss showers or even a rumble of thunder tonight. 

&&

.KEY MESSAGES...

- Backdoor cold front brings cooler temps and northeast winds to
  northern/eastern MA today. 

- Mild tonight with hit or miss showers, with thunder also 
  possible. 

- Cold front moves thru Thurs, bringing rain and falling temps 
  through the day. Even a risk for minor snow accumulation in 
  interior Southern New England Thurs depending on the timing. 

- Potential for strong winds and heavy rain later Sunday and
  Monday which may lead to minor river flooding.

&&

.DISCUSSION...
Key Message 1...Backdoor cold front brings cooler temps and 
northeast winds to northern/eastern MA today. 

A backdoor cool front is taking shape early this morning in northern 
ME and is expected to build southward thru ME/NH thru early 
overnight and into eastern and central MA by the early morning hours 
and then eventually stalling into CT/RI by late in the morning. 
North of the boundary, expect an overcast and raw day with NE winds 
and temps either hovering or slowly falling for a time (some areas 
today in northern MA may struggle to get out of the mid 40s), with 
warmer temps south and west of the frontal boundary (highs in the 
lower 60s for CT and southern RI). Other than hit or miss showers on 
the cool side of the frontal boundary, most of the daytime period 
should be largely dry. In response to strong southerly flow and warm 
advection, this boundary returns back northward as a warm front 
during the afternoon to early evening, which then brings with it a 
surge in temps and dewpoints. So for areas in northern and northeast 
MA on the north side of the frontal boundary, calendar-day highs are 
more likely to be met after sundown.

Key Message 2...Mild tonight with hit or miss showers, with 
thunder also possible. 

Ahead of a powerful but slowing cold front, a strong burst of 
warm/moist advection takes place tonight on 850 mb winds around 45-
55 kt. This brings rising dewpoints (in the 50s) and PWAT values of 
up to 1.5 inches, as well as decreasing the static-stability above 
the strong frontal inversion. Most models show showalter indices 
dropping below 0 indicative of elevated instability...but the degree 
to which they do and what may force any shower activity is in some 
question. Similar to yesterday the 00z NAM shows a very-probably-
overdone look with lapse rates above 700 mb around 7 C/km, which 
generates an exorbitant amount of MUCAPE around 1500 J/kg. RAP and 
GFS MUCAPEs seem more realistic at around 200-400 J/kg. This could 
be enough to produce some thunder and have included a mention of 
thunder in with the chance-level PoP during the evening. It 
also looks like the forcing is slower to arrive, which lends 
itself to questions on what may get any showers going. And it 
could be from remnant convective activity in the mid-Atlantic
given more active thunderstorms anticipated there today, as 
offered by some high- res solutions. With the front now slower 
to lurch into the Berkshires, low temps look to stay in the low 
to mid 50s in most areas given the southerly winds and overcast.

Key Message 3...Cold front moves thru Thurs, bringing rain and 
falling temps through the day. Even a risk for minor snow 
accumulation in interior Southern New England Thurs depending 
on the timing. 

Cold front then moves into SNE Thurs, which is when the best chance 
for widespread precipitation sets in. Much of this will initially 
fall as rain, but strong shallow cold advection should allow for 
falling temps through the day. One thing to watch is the potential 
for anafrontally-forced precipitation Thurs aftn as secondary 
shortwave trough in the central Appalachians draws moisture 
northward from the mid-Atlantic on the cold side of the frontal 
boundary, into an airmass which would be cold enough for a minor 
accumulation of wet snow. If that were to happen, minor accumulating 
snow could develop with better chance in interior Southern New 
England. While snow in March is not uncommmon, considering the mid 
to upper 70s some areas saw on Tuesday it would be quite a whiplash.

Mild temps from the overnight (mid 50s) should serve as Thurs's 
highs, with hourly temps then falling steadily through the day.



KEY MESSAGE 4...Potential for strong winds and heavy rain later
Sunday and Monday which may lead to minor river flooding.

Even though melting snow has brought increased river and stream 
flows, we don't see much of a flood concern until Monday with the 
arrival of potentially heavy rainfall and strong winds. Rises on
mainstem Connecticut River this weekend should remain below
flood stage.

Ensemble situational awareness tables indicate the potential for a 
highly anomalous event in terms of rainfall and strong winds, with 
several wind and moisture parameters above the 90th percentile and 
in some cases near the max of model climate. This is ahead of a more 
amplified upper trough which will bring strong southerly flow and 
deep moisture into southern New England resulting in a widespread 
and potentially heavy rainfall event along with a brief surge of 
warmth.

Probabilities for 1"+ of rain are currently centered more across CT, 
RI, and SE MA, and as a result ensemble river forecasts show the 
potential for minor flooding beginning Monday along the Pawtuxet, 
Pawcatuck, and Wood Rivers in RI and perhaps along the lower reaches 
of the mainstem Connecticut River from Hartford through Middle 
Haddam.

It's tough to mix down strong winds this time of year with southerly 
flow events, but areas that are usually favored are the immediate 
South Coast, Cape Cod, and the Islands. Assuming we have a strong 
inversion, which is typical in March, we can estimate gusts taking 
about 50% of 925 mb winds. GFS shows a peak of 70-75kt Mon morning 
which would yield 35-40kt gusts and Gales on the coastal waters. 

Behind a strong cold front, we look to be in for another brief surge 
of cold with below average temperatures in the 30s Tuesday.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

06z TAF Update: 

Through 12z Wednesday: Moderate confidence.

VFR prevails through at least 08z, then a backdoor cold front 
beings a NE wind shift, IFR stratus and drizzle/mist to BOS/BED 
and perhaps as far south as ORH by 09-12z. 

Today: Moderate confidence. 

IFR with NE winds, drizzle and mist for BOS-BED-ORH with VFR
elsewhere. As backdoor front returns northward as a warm front,
expect modest improvement to MVFR-IFR in most areas, timing 
approx 16-20z with winds becoming SE/S.

Toight: Moderate confidence. 

MVFR/IFR ceilings ahead of approaching cold front. Isolated
showers/possible thunder rumbles south of the Mass Pike before
cold front comes in approx 03-07z and moves into central MA/CT
by 12z. SW winds around 10-12 kt with low level wind shear
likely. 

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday: Mainly VFR, with local IFR possible. Windy with gusts
up to 30 kt. RA likely, chance SN.

Thursday Night: VFR. Breezy. 

Friday: VFR. Breezy. Slight chance RA.

Friday Night: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 30 kt. Chance RA.

Saturday: VFR. Windy with gusts up to 30 kt. 

Saturday Night: VFR. Breezy. 

Sunday: VFR. Breezy. Slight chance RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

A backdoor cold front will be working southward from the 
coastal ME waters which will bring an increased NE wind to the 
waters today at around 10-15 kt which then becomes ESE/SE late 
in the day. Elsewhere winds mainly southerly today around 10-15 
kt, increasing to around 20 kt southern waters late.

SCAs hoisted on most waters starting early this evening and
through midafternoon Thurs as southerly winds increase to around
25-30 kt in gusts. Seas will also be building to 5-10 ft thru
Thurs. Winds will eventually shift to NW late Thurs afternoon
to SCA criterion.

Outlook /Thursday through Sunday/...

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Rain. Local visibility
1 nm or less.

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. 

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

Friday Night: Strong winds with gusts up to 35 kt. Areas of
rough seas. Chance of rain. 

Saturday: Strong winds with gusts up to 35 kt. Rough seas up to
11 ft. 

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of seas approaching 5 ft. 

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 8 PM this evening to 2 PM EDT 
     Thursday for ANZ232>235-237-250-254>256.

&&

$$

DISCUSSION...KJC/Loconto
AVIATION...KJC/Loconto
MARINE...KJC/Loconto