480
FXUS61 KBOX 192347
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
747 PM EDT Sat Apr 19 2025

.SYNOPSIS...
Scattered showers and possibly a rumble of thunder later this
afternoon and evening. Drier and mild behind a cold front
Sunday with gusty northwest winds. Low pressure should pass by
to our north Tuesday. High pressure then expected to linger
nearby into Friday with above normal temperatures.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Messages

* Showers associated with a passing cold front taper off the east
  coast by midnight

* Rapid clearing overnight with winds shifting to the
  northwest behind the cold front

Tonight

A strong cold front ushers out the abnormally warm air mass that is
in place this afternoon. Scattered showers should taper off the east
coast between roughly 8-11PM. Still can`t rule out a rumble of
thunder, but instability should be waning in the hours following
sunset. Winds shift to the northwest overnight and remain
strong/gusty with sustained winds from 15 to 20 mph and wind
gusts from 25 to 35 mph.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Key Messages

    * Gusty northwest winds (25-35 mph) and low relative
      humidity (20-30%) tomorrow may support elevated fire
      weather conditions across southern New England tomorrow
      afternoon

    * Gusty winds diminish tomorrow night as high pressure
      builds in from the west to start next week

Tomorrow and Tomorrow Night

Temperatures will be more seasonable tomorrow as 925 hPa temps
dip to 5C in the wake of the passing cold front. Steep low-level
lapse rates will support deep diurnal mixing, so we can expect
high temperatures to top out in the upper 50s to low 60s. The
low-level jet will continue to be fairly strong tomorrow
afternoon, especially across the eastern half of southern New
England. Thus, we`ll be looking at another afternoon with gusty
winds out of the northwest between 25 and 35 mph. The atmosphere
will be substantially drier as well with dewpoints falling to
the 20s across much of southern New England. This will support
very low RH values between 20 and 30 percent. With the dry
conditions and gusty winds, a special weather statement for
elevated fire weather concerns will likely be in the cards for
tomorrow. This will hinge on how much precipitation we receive
with the showers we`re expecting this afternoon and evening.

Winds will gradually weaken Sunday night into Monday as high
pressure builds in from the west and helps relax the pressure
gradient. Mechanical mixing may limit radiational cooling for the
first half of the night, but as winds weaken to light/variable the
rate of cooling should increase in the hours approaching sunset.
Generally expect lows in the mid 30s across the region for Monday
morning.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Messages:

* Dry for much of Monday with light NW winds shifting more southerly
  into the afternoon

* Showers Monday night into Tuesday, dry through most of the week,
  then another round Friday

* Temperatures next week remain slightly above normal

Monday through Tuesday:

An upper level ridge and associated surface high push into southern
New England Monday bringing light NW winds to start the day. As the
high moves offshore through the day, winds will become more
southerly, except for the eastern coast where winds will likely be
more easterly with a sea breeze in the afternoon. Temperatures trend
slightly cooler than Sunday with highs in the 50s closer to the
coastline and low 60s across interior southern New England. It will
be dry much of the day with showers likely not arriving until Monday
night. Although there is a low chance (< 20%) for an isolated shower
in the early evening timeframe.

A round of showers move through Monday night into Tuesday with light
rainfall amounts expected. Tuesday likely stays unsettled for the
morning, as any remaining showers exit off to the east, followed by
gradually drying conditions in the afternoon. Weak warm advection
will bring 850mb temperatures in the 9-12C range Tuesday. This will
support above normal temperatures in the 60s and lower 70s with the
exception of the Cape/Islands in the high 50s.

Tuesday Night through Friday:

A cold front moves through Tuesday night into early Wednesday
morning bringing a slightly cooler airmass in for Wednesday... still
slightly above normal temps with highs in the 60s in most places. A
similar pattern stays in place through the end of the week with
zonal flow and 850mb temperature anomalies signaling slightly above
normal temperatures. Ensembles indicate the potential for the
passage of a low sometime Friday/Saturday possibly bringing some
showery conditions for the weekend; however, it`s too far out to
make any concrete conclusions at this time.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

00Z Update...

Tonight...High Confidence

Mainly VFR. Brief borderline MVFR ceilings may accompany cold
front with isolated to widely scattered SHRA through
03Z. Front moves through after midnight with rapid clearing
behind it and switch to NW winds with gusts 25-40 kt. The higher
end of that range possible for higher terrain terminals
briefly (ORH). Strong LLWS 40-55 knots over Cape/Islands
terminals

Sunday...High confidence.

VFR. NW winds with gusts of 20-30 kt. Gusts diminish towards
sunset.

Sunday Night... High Confidence.

VFR. Northwest winds gradually become light and variable by 12Z.

KBOS TAF...High confidence in flight categories. Less confidence
in precip timing. Gusty W winds veering NW 12Z-14Z.


KBDL TAF...High confidence in TAF.

Outlook /Monday through Thursday/...

Monday: VFR.

Monday Night: Mainly VFR, with local IFR possible. Breezy. SHRA
likely.

Tuesday: Mainly VFR, with local IFR possible. Breezy. Chance
SHRA.

Tuesday Night: VFR. Breezy.

Wednesday through Thursday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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


Tonight through Tomorrow Night

SCY conditions persist overnight for the southern marine zones
as a cold front crosses the water this evening. Winds shift from
southwest to northwest but remain on the strong side with 15 to
20 knot sustained winds and gusts up to 30 knots. Wind gradually
weaken during the afternoon tomorrow and become much lighter
tomorrow night as high pressure builds in from the west. Seas
gradually subside below SCY criteria tomorrow as well.

Outlook /Monday through Thursday/...

Monday: Winds less than 25 kt.

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

Tuesday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers.

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

Wednesday through Thursday: Winds less than 25 kt.

&&

.FIRE WEATHER...
SPS for elevated fire weather will be likely for tomorrow for
southern New England. A drier air mass filters into the region
behind a cold front crossing the region this afternoon. Gusty
northwest winds tomorrow afternoon with gusts up to 35 mph
combined with low relative humidities between 20 and 30 percent
could result in fast spread of any wildland fires. Potential
will also hinder on how much precipitation we get from a round
of showers ahead of the approaching cold front this afternoon
and evening. A final decision on a headline will be made
overnight once the aforementioned showers have exited the
region.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ231.
     Small Craft Advisory until 1 AM EDT Sunday for ANZ232-234-236.
     Small Craft Advisory until 7 AM EDT Sunday for ANZ233.
     Small Craft Advisory until 7 PM EDT Sunday for ANZ235-237-250-
     254>256.

&&

$$

SYNOPSIS...McMinn/RM
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...McMinn
AVIATION...McMinn/RM
MARINE...McMinn/RM
FIRE WEATHER...RM