NWS Forecaster Discussion
BOX
Area Forecast Discussion National Weather Service Boston/Norton MA.
843
FXUS61 KBOX 140543
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
143 AM EDT Sat Mar 14 2026
.WHAT HAS CHANGED...
Expanded the Wind Advisory into Cape Cod, Martha`s Vineyard and
Nantucket for today, while also upgrading marine headlines to
Gale Warnings for all waters.
&&
.KEY MESSAGES...
- Variable amounts of cloud cover, cooler than normal with
strong west wind gusts 35-50 mph today.
- A period of heavy rainfall Mon into Mon night may lead to some
river and small stream flooding. A period of strong to
damaging wind gusts possible Mon night.
- Mainly dry weather and trending colder through midweek then
moderating toward the end of next week.
&&
.DISCUSSION...
Key Message 1...Variable amounts of cloud cover, cooler than normal
with strong west wind gusts 35-50 mph today.
Strong Clipper low pressure system is expected to pass to our
north and into the Canadian Maritimes by tonight. Pretty tight
pressure gradient combined with efficient if still shallow
mixing from a strong cold advection pattern should help to
promote gusty to strong westerly wind gusts today. This system
has had a history of strong westerly winds yesterday (e.g.
several instances of 50 to 60 mph gusts) in the eastern Gt Lakes
region, but the westerly lower-level jet doesn`t look nearly as
robust as it did yesterday, although is still considerable at
around 45-50 kt at 850 mb.
Boosted wind gusts upward some for today, and most areas should
end up gusting in the 35-45 mph range; however gusts could
punch as high as 50 mph across the Berkshires, northern hills of
Worcester County and down across the Cape and Islands where the
existing Wind Advisory has now been expanded further into. This
is supported by BUFKIT momemtum transfer progs as well as the
00z HRRR 10-m wind gust speeds, and the HREF ensemble minimum
10-m gust is also around 40-45 kt in the Advisory areas.
Westerly gusts should really pick up once the sun comes out this
morning but should peak into the afternoon as the core of the
low-level jet crosses Southern New England. Gusts should drop
below 40 mph by late afternoon, with a steadier decrease into
the night as winds turn more northwesterly and lighter.
It wouldn`t take much more of an increase in gusts to warrant
expanding the Wind Advisory further into Southern New England,
especially given continued early-morning observations of 35-45
kt gusts across western NY and the Gt Lakes. It does look to be
at least a variably-cloudy day (more clouds north and fewer
south) as moisture continues to wrap-around from the Clipper
system, which casts some uncertainty in the mixing depth and
that was a factor in deciding not to expand the Advisory into
remainder of Southern New England. Other than the cloud cover,
there may also be some scattered flurries or sprinkles dotting
the area as this is a favorable setup for Gt Lakes moisture to
be advected quite a distance downwind given the enhanced
westerly jet, but this should be fewer and far betweeen and not
impactful. Besides the windy conditions and the variable amts of
cloud cover, today is otherwise a cooler day with highs in the
upper 30s to low 40s, a couple degrees cooler than normal but
the wind will add a bit of chill.
KEY MESSAGE 2...A period of heavy rainfall Mon into Mon night may
lead to some river and small stream flooding. A period of strong to
damaging wind gusts possible Mon night.
Ensemble guidance showing a strong signal for a heavy rainfall and
strong wind event Mon into Mon night. PWAT and low level wind
anomalies 3-4 SD above normal which is near the maximum of the CFSR
climatology. This occurs ahead of a deep and amplified upper trough
over the Gt Lakes which sends anomalous moisture northward into New
Eng. Expect numerous showers Mon as anomalous PWAT plume overspreads
the region within the low level jet axis. There is also some
elevated instability so potential exists for heavy convective
showers and a few t-storms as well. These locally heavy showers and
isolated thunder will continue into Mon night. Given the strong
forcing along the boundary along with some elevated instability a
fine line of convection may develop along the front as it moves
through during Mon night. The front should be moving off the coast
by Tue morning with rapid drying moving from west to east. We are
still expecting average rainfall of 1-2 inches with localized
amounts up to 3 inches. 90th percentile of the ensemble QPF
distribution continues to show rainfall amounts up to 3 inches which
likely represents a high end potential from convection. MMEFS
ensemble guidance continues to target RI rivers (Pawcatuck, Wood and
Pawtuxet) and the lower reaches of the CT River from Hartford to
Middle Haddam with the highest probabilities for (50-80%) for minor
flooding during Tue-Wed timeframe.
While winds will be ramping up during Mon, the worst of the wind
will likely be focused during the Mon night period just ahead of the
cold front. This is when the maximum of the low level jet lifts
across the region. NAM is indicating 85-90 kt LLJ at 925 mb moving
across SE New Eng. Even the global guidance is showing 75-80 kt.
Soundings do show a low level inversion which is normal with these
southerly LLJ events so the challenge is determining how much wind
can mix down. The key will be how mild it gets Mon evening ahead of
the cold front and whether a fine line of convection can develop
along the front which would increase potential for mixing strong
winds to the surface. These are factors that should become more
clear as we get within the hi-res window later this weekend. A quick
look at the soundings suggest temps near 60 would increase damaging
wind potential and there is certainly a chance we see temps get to
60 in some locations. But just taking 50 percent of the LLJ as an
initial estimate with a strong inversion in place would support 45-
55 mph gusts, while a weakened inversion with milder temps would
increase potential for 55-65 mph gusts.
KEY MESSAGE 3...Mainly dry weather and trending colder through
midweek then moderating toward the end of next week.
It appears the front will have moved east of New Eng before 12z Tue
with much drier air moving in from the west so expecting mainly dry
weather Tue. The dry weather will continue Wed & Thu and possibly
into Fri as well but we may have to contend with a shortwave and
cold front which could bring a low risk for showers on Fri. It will
be trending colder with the coldest day on Wed as 850 mb temps
bottom out around -15 to -18C at 12z Wed. Highs Wed expected to be
mostly in the 30s to near 40. Then temps gradually moderate Thu into
Fri getting back to seasonable normals by Fri.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
06z TAF Update:
Through 12z Saturday: High confidence.
Areas of MVFR/temporary IFR-visby SHSN to move offshore by
07-08z, then rapid improvement to VFR. Winds become SW/WSW and
increasing to around 13-16 kt with gusts to 25 kt.
Today: High confidence.
SCT-BKN VFR ceilings (035-050) should predominate, though some
MVFR ceilings possible across northern MA. Outside chance at
passing rain/snow showers in Gusty WSW to W winds around 15-25
kt, with gusts 35-45 kt highest at ORH, on Cape Cod/ACK and in
the Berkshires. Gusts should slowly ease around 25-35 kt late
Sat while becoming W/WNW.
Saturday Night: High confidence.
VFR. Easing WNW winds to around 5-10 kt thru evening/overnight.
KBOS Terminal...High confidence in TAF. MVFR-visby SHSN should
exit by 07z. VFR but with gusty WSW to W winds Sat, easing
trends into Sat early evening.
KBDL Terminal...High confidence in TAF. VFR, gusty WSW to W
winds thru Sat, easing trends into Sat late-afternoon.
Outlook /Sunday through Wednesday/...
Sunday: VFR. Breezy.
Sunday Night: Mainly VFR, with local IFR possible. Windy with
local gusts up to 30 kt. Chance RA, chance FZRA.
Monday: Mainly MVFR, with areas IFR possible. Strong winds with
areas of gusts up to 40 kt. RA, slight chance TSRA.
Monday Night: Mainly MVFR, with local IFR possible. Strong
winds with gusts up to 50 kt. RA, isolated TSRA.
Tuesday: VFR. Windy with gusts up to 35 kt.
Tuesday Night: VFR. Windy with local gusts up to 30 kt.
Wednesday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
High confidence.
Have upgraded SCAs/Gale Watch to Gale Warnings, which now cover
all waters for today into early tonight. Gusts look to punch a
little higher than prior expectations, with westerly gusts in
the 35-45 kt range, but on the higher end of that range over the
southern/southeast waters. Expect rough seas especially
eastern/southern outer waters. Gradual decrease in winds and
seas through SCA range into tonight and early Sunday AM.
Winds and seas then decrease below SCA criterion for Sunday.
However increasing southerly winds ahead of a strong low
pressure should take place starting Sunday night. Gale/Storm
Watches could become necessary very late Sunday night/early
Monday.
Outlook /Sunday through Wednesday/...
Sunday: Winds less than 25 kt.
Sunday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Local rough seas. Chance of rain.
Monday: Moderate risk for gale force winds with gusts up to
45 kt. Rough seas up to 15 ft. Rain, slight chance of
thunderstorms.
Monday Night: gale force winds with gusts up to 45 kt. Rough
seas up to 19 ft. Rain, isolated thunderstorms.
Tuesday: Strong winds with gusts up to 35 kt. Rough seas up to
15 ft. Slight chance of rain.
Tuesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Rough seas up to 14 ft.
Wednesday: Winds less than 25 kt. Areas of rough seas.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Wind Advisory from 10 AM this morning to 7 PM EDT this evening
for MAZ002-004-008-009-022>024.
RI...None.
MARINE...Gale Warning until 11 PM EDT this evening for ANZ230>237-250-
251-254.
Gale Warning until 11 PM EDT this evening for ANZ255-256.
&&
$$
DISCUSSION...KJC/Loconto
AVIATION...KJC/Loconto
MARINE...KJC/Loconto