072
FXUS61 KBOX 031112
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
712 AM EDT Thu Apr 3 2025

.SYNOPSIS...
A warm front will bring showers this morning followed by windy and
milder conditions this afternoon. A cold front will push southward
across the region tonight and may lead to a few showers, especially
south of the Mass Pike which may linger along the south coast early
Friday. High pressure brings drier and mild conditions Friday.
Turning much cooler Saturday with showers returning as a frontal
system approaches, then milder Sunday with continued unsettled
conditions. Drying out Monday as the frontal system exits the region
followed by cooler than normal temperatures overspreading the area
much of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages:

* Showers this morning with brief downpours possible

* Windy and milder this afternoon. A few gusts to 40 mph possible

Lull in the precip this morning with just areas of drizzle, but
additional showers upstream assocd with mid level shortwave. Mid
level shortwave crosses the region this morning. Deep moisture
plume combined with marginal elevated instability will result in
numerous showers redeveloping and moving across SNE this
morning, initially across the interior before shifting to the
south coast late morning and early afternoon. The instability
aloft has produced some lightning to the NW so can`t rule out an
isolated rumble of thunder and a few showers may contain brief
downpours given PWATs approaching 1.5".

We should see somewhat of a drying trend this afternoon with
decreasing coverage of showers as the shortwave exits and some
drying moves in aloft. The warm front will be lifting northward
across the region by afternoon with increasing SW flow bringing
milder air northward into SNE as 925 mb temps increase to 14-16C.
Normally this would support temps well into the 70s but cloud cover
and shallow mixed layer will limit how warm it gets. We should see
temps rise into the 60s away from the south coast, with the chance
of a few locations in the CT valley could reach 70+. 75th percentile
of NBM has highs near 70 in the CT valley and interior NE MA but
confidence is low due to cloud cover. Expect cooler 50s along the
immediate south coast.

It will become windy later this morning and afternoon as warm sector
overspreads the region. We have a 55-65 kt low level jet across
eastern half SNE. Inversion will limit how strong gusts will get,
but warming temps this afternoon will help to weaken the inversion
and support gusts to 30-40 mph.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Key Messages:

* A few showers tonight, especially south of MA Pike

* Increasing sunshine from north to south Fri with above normal temps

Northern stream shortwave moving across eastern Canada will push a
cold front southward into SNE tonight and can`t rule out a few spot
showers. There is an increase in elevated instability from the SW
which moves into the region in the evening which may result in a few
convective showers near the south coast this evening. The
instability moves to the south overnight, but developing deeper
moisture axis sets up near the south coast ahead of the front with
PWATs near 1.5", so may see a few additional showers develop near
the south coast late tonight into early Friday. Where these showers
set up is uncertain and could end further north or south.

Good drying trend for Friday as much drier air moves southward
across the region with PWATs falling to 0.25-0.50". There is a low
risk a few showers could linger near the south coast early Fri,
otherwise clouds will give way to increasing sunshine from N to S.
It may take until the afternoon for sunshine to develop near the
south coast. It will be a mild day with highs in the 60s and modest
NW breezes 10-20 mph.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Long Term

Key Messages

* Cooler on Saturday followed by increasing warmth and shower
  chances Saturday night into Sunday

* Unsettled early next week with seasonable temperatures

Saturday through Sunday night.

High pressure builds north and east of southern New England Friday
night into Saturday. This will allow a backdoor cold front to advect
cooler air into the region with 925 hPa temps dipping near the
freezing mark by Saturday morning. This will support a cool/raw day
with highs peaking in the mid to upper 40s for much of southern New
England. Saturday will as mark the beginning of a wet/unsettled
period for the forecast area that will carry into next week. As the
aforementioned area of high pressure continues to shift east, return
flow from the south will support WAA driven showers over southern
New England likely beginning Saturday afternoon. Expect
precipitation to persist through Sunday as the associated low-
pressure system traverses over The Northeast Saturday night through
Sunday evening.

As warm sector air lifts over the region on Sunday, 925 hPa temps
rise dramatically to the 15 to 20C range. So while Sunday is
expected to be wet/rainy, it will also be on the warm/humid side
with temperatures in the low to mid 60s and dewpoints in the 50s.
Ensemble mean precipitation forecasts for Saturday afternoon through
Sunday night are ranging from 0.75 to 1 inch across southern New
England. Some of this precip may come in the form of convective
showers Sunday night as the associated cold front drives the warm
sector air out of the region. Model derived CAPE values are
unimpressive at this time, but with ensemble mean SBCAPE values
around 250 J/kg, a few showers could have a rumble of thunder,
particularly along the south coast.

Monday through Wednesday

Showers associated with a passing cold front exit off the east coast
early Monday. Despite the dry/northwest flow that will follow,
unsettled weather looks to continue Monday and Tuesday as a second
pulse of short-wave energy digs east over The Midwest toward
southern New England. Moisture will be lacking, so while we aren`t
anticipating any substantial precipitation from this short-wave, we
do expect more clouds than sun with some sporadic showers.
Temperatures looks to be seasonable with ensemble means supporting
highs/lows in the upper 40s to 50s and mid to upper 30s respectively
Monday and Tuesday. Details become vague as we reach the middle of
next week, but there is strong support from ensembles for below
normal temperatures as a broad upper-level trough is expected to
bring a surge of cooler air to the Northeast for the middle of
next week.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Today...Moderate Confidence.

Widespread IFR with stratus and fog and drizzle, then numerous
showers developing this morning from the west. Showers becoming
more spotty in the afternoon. Areas of LIFR with areas of dense
fog developing along the south coast mid-late afternoon.
Increasing SW winds with gusts to 25-35 kt developing.

Tonight...Moderate Confidence.

IFR/MVFR improving to VFR from NW to SE with passage of a cold
front. LIFR fog near the south coast improving overnight.

Friday... High Confidence

VFR. West/northwest winds 10-20 kt.

BOS TAF...Moderate confidence. IFR should improve to cigs around
1000 ft this afternoon as gusty SW winds develop.

BDL TAF...Moderate confidence.

Outlook /Friday Night through Monday/...

Friday Night: Mainly VFR, with local MVFR possible.

Saturday: Mainly MVFR, with local IFR possible. Breezy. SHRA.

Saturday Night: Mainly MVFR, with areas IFR possible. Breezy.
SHRA.

Sunday: Mainly MVFR, with local IFR possible. Breezy. Chance
SHRA.

Sunday Night: Mainly MVFR, with local IFR possible. Breezy.
SHRA likely.

Monday: Mainly MVFR, with local IFR possible. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through tonight...High confidence.

Gusty SW winds today with low level jet over the waters. Gusts to 25-
35 kt with strongest gusts over nearshore waters. A few marginal
gale force gusts possible. Winds diminish tonight and shift to NW
late tonight. Seas build to 7-9 ft over the outer waters. Occasional
showers with areas of dense fog developing this afternoon into this
evening with poor vsbys, improving late tonight.

Friday...High confidence.

W-NW winds 10-20 kt with subsiding seas. Scattered showers
possible over southern waters early.

Outlook /Friday Night through Monday/...

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

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers.

Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Rain
showers.

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. Chance of rain showers.

Sunday Night: Winds less than 25 kt. Areas of rough seas. Rain
showers likely.

Monday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ230.
     Small Craft Advisory until midnight EDT tonight for ANZ231-251.
     Gale Warning from 11 AM this morning to 6 PM EDT this evening
     for ANZ232>234.
     Small Craft Advisory until 8 AM EDT Friday for ANZ235-237.
     Small Craft Advisory until 10 PM EDT this evening for ANZ236.
     Small Craft Advisory until 5 AM EDT Friday for ANZ250.
     Small Craft Advisory until 2 PM EDT Friday for ANZ254>256.

&&

$$

SYNOPSIS...KJC/RM
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...RM
AVIATION...KJC/RM
MARINE...KJC/RM