363
FXUS61 KBOX 091920
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
320 PM EDT Sun Mar 9 2025

.SYNOPSIS...

Sunshine and mild temperatures are in store for Monday and
Tuesday. Cooler on Wednesday and a chance of light showers on
Thursday. Warmer temperatures Friday through the weekend with
the next chance for accumulating rainfall arriving late weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...

Key Messages...

* Considerable clouds tonight...but nothing more than a passing
  flurry across northern MA, lows in the upper 20s to the middle 30s

Details...

Initial mid level warm front was moving across the region late this
afternoon with just some clouds and perhaps a brief flurry in
northwest MA. The clouds associated with this system will push east
of the region early this evening. However...another clipper system
will be tracking across northern New England later tonight. This
should again just bring more clouds to our region with perhaps a
brief passing snow flurry or two across northern MA...mainly near
and north of Route 2. Otherwise...the clouds should keep overnight
temps mainly in the upper 20s to the middle 30s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...

Key Messages:

* Sunshine returns Mon...Highs in the 50s to perhaps near 60 in spots
* Dry Mon night with lows in the 20s & 30s

Details...

Monday...

In the wake of the clipper system tracking to our north tonight...a
westerly flow of dry air will work into southern New England on Mon.
Plenty of sunshine returns Mon along with fairly mild temperatures.
925T warm to between +4C and +6C and with good mixing and plenty of
March sunshine...Highs should top off well into the 50s to perhaps
even near 60 in spots. Westerly winds of 10 to 20 mph will weaken as
the day wears along...so localized sea breezes may develop along
portions of the immediate coast late in the afternoon/early evening.
Nonetheless...a very nice day is in store for the region but it may
turn cooler by late afternoon/early evening along portions of the
immediate coast.

Monday night...

A ridge of high pressure will remain in control of our weather Mon
night. This will result in a mainly clear skies/light winds and a
good night of radiational cooling. Lows Mon night should bottom out
in the 20s across the outlying locations to the 30s in some urban
centers.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...

Tuesday and Wednesday:

Stronger SW flow aloft develops for Tuesday ahead of a weak
shortwave trough. 850mb temperatures increase to 4-6C. This will
support a mild day with highs in the 50s in most spots. A few spots
across the interior have a shot at 60, especially in the valleys.
The south coast and Cape/Islands will stay on the cooler end thanks
to the cooler marine air with highs in the upper 40s to around 50.
It will be breezy with southerly winds with gusts 20-30 mph.

A weak mid-level trough moves through overnight into Wednesday with
a cold front. This will bring NNW/N flow and cooler temperatures for
Wednesday. Highs range in the 40s for most areas. If northerly flow
becomes more NNE/NE, the added onshore component may keep coastal
areas along the eastern waters even cooler in upper 30s/low 40s.

Thursday through weekend:

A weak mid-level shortwave trough moves through the flow Thursday
into Friday. Ensemble and deterministic guidance have stayed
consistent with the continued downward trend in precipitation
chances/QPF with this system. The system overall lacks
synoptic-scale support with the moisture being mainly in the
mid-levels with WAA. Ensemble means still signal the chance for
some light showers Thursday and Thursday night. Model soundings
show dry intact at the surface which will make it difficult for
it to reach the ground and support more virga. We could still
see low chances (< 30%) for scattered showers, perhaps a few
flakes across the northern higher elevations spots across
interior MA for AM showers Thurs. Temperatures will be
seasonable in the 40s by the afternoon.

Warming trend for Friday into the weekend with warm advection and
height rises. This should help warm temperatures back into the 50s
Friday with potential for highs in the low 60s for many areas over
the weekend. There is a good consensus among model guidance for a
system to move through for the second half of the weekend bringing
our highest chance for seeing accumulating rain. More details to
come as we get closer.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...

Forecast Confidence Levels:

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

18z TAF Update...

This afternoon...High Confidence.

VFR with mid level cloudiness overspreading the region. WSW
wind gusts of 20 to 25 knots with a few gusts up to 30 knots.

Tonight...High Confidence.

VFR with another round of mid level cloudiness later in the
evening and into the overnight hours. SW winds mainly 5 to 10
knots.

Monday...High Confidence.

VFR. WNW winds of 8-14 knots with some 20+ knot wind gusts into
the early afternoon. The gradient may weaken enough to result in
sea breezes along the eastern MA coast near or after 21z.

Monday night...High Confidence.

VFR. Light/Calm S winds.

KBOS TAF...High confidence in TAF. The only uncertainty is
whether a sea breeze develops Mon after 21z.

KBDL TAF...High confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday through Wednesday: VFR. Breezy.

Wednesday Night: VFR.

Thursday: Mainly VFR, with local MVFR possible. Slight chance
RA.

Thursday Night: Mainly VFR, with local IFR possible. Slight
chance RA.

Friday: Mainly VFR, with local IFR possible.

&&

.MARINE...

Forecaster Confidence Levels:

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

Tonight through Monday night...High Confidence.

Small craft SW wind gusts/seas will linger tonight across most open
waters...but drop below criteria in Boston Harbor and Narragansett
Bay early this evening with the loss of diurnal heating. A clipper
system passing to our north overnight will result in winds shifting
to more of a westerly direction by Mon. Most locations will have
winds/seas below small craft advisory criteria by Mon morning...but
lingering marginal small craft winds/seas across expected into Mon
afternoon for our southern outer-waters. A ridge of high pressure
building in Mon night should result in our entire region seeing
winds/seas below small craft advisory thresholds.

Outlook /Tuesday through Friday/...

Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas locally approaching 5 ft.

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

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

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

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

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ230-
     236.
     Small Craft Advisory until 8 AM EDT Monday for ANZ231>235-237-
     250-251-254.
     Small Craft Advisory until 5 PM EDT Monday for ANZ255-256.

&&

$$

SYNOPSIS...Frank/Mensch
NEAR TERM...Frank
SHORT TERM...Frank
LONG TERM...Mensch
AVIATION...Frank/Mensch
MARINE...Frank/Mensch