380
FXUS61 KBOX 202336
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
736 PM EDT Sun Apr 20 2025

.SYNOPSIS...
High pressure will bring dry conditions with less wind tonight and
Monday. Scattered showers return Monday night into early Tuesday as
a weak front moves through followed by dry conditions with above
normal temperatures Tuesday afternoon into Friday. A frontal system
may bring more showers Friday night into Saturday, then drying out
next Sunday as the system moves offshore.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Key Messages:

* Mainly clear with diminishing wind and low temps in the 30s

Upper level ridging builds in from the west tonight as surface high
pres builds to the north. Very dry air and subsidence will lead to
mainly clear skies although some high clouds will move in from the
west. Gusty winds this afternoon will diminish this evening and
become light to calm overnight. This will result in good radiational
cooling and a chilly night with lows dropping into the low-mid 30s,
with some upper 20s possible in the colder spots in NW MA.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Key Messages:

* Dry and mild Monday with sea-breezes developing
* Scattered showers developing Mon night

Monday...

Upper level ridge axis will be over New Eng as high pres shifts SE
of New Eng during the afternoon. Sunshine will give way to
increasing high clouds in the afternoon. 850 mb warm front moves
through with rapid increase in 850 mb dewpoints and increasing PWATs
in the afternoon. However, expect dry weather to persist through the
day as soundings show enough low level dry air that will need to be
overcome. Highs will reach low-mid 60s inland, but hold in the 50s
near the coast as cooling sea-breezes develop.

Monday night...

The high pres moves further offshore with weak cold front
approaching from the west. A modest pre-frontal low level jet will
lead to good moisture transport as PWATs increase over 1 inch. This
combined with marginal elevated instability will result in scattered
showers sweeping through the region from W to E during the late
evening and overnight. Lows will range through the 40s with modest
southerly breezes.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Key Messages:

* Showers linger into Tuesday morning.

* Mainly dry Wednesday and Thursday with temperatures slightly above
  normal.

* Pattern becomes more unsettled Friday through the weekend with
  periodic chances for precipitation.

Tuesday through Thursday:

Showers linger through the morning Tuesday as a cold front
pushes across the CWA. Weak warm advection ahead of the front
will bring 850mb temperatures in the 8-10C range Tuesday. This
will support above normal temperatures in the 60s and low 70s
with the exception of the Cape/Islands in the 50s.

Temps will quickly begin to cool off Tuesday evening as a colder and
drier airmass moves into place post-FROPA. Wednesday`s high temps
will be slightly cooler than Tuesday`s, but still above average...
high 60s for most areas, with a small chance (< 20 percent) some
urban areas could hit 70F.

Broad high pressure begins to build over the southeastern waters for
Thursday, bringing another day of clear skies and dry weather. High
temps for the interior likely range from high 60s to low 70s while
the immediate coast, Cape, and Islands likely remain in the high 50s
to low 60s.

Friday through the Weekend:

Ensemble guidance indicates a transition to a more unsettled pattern
sometime Friday afternoon or evening into Saturday morning with
potential for periodic chances for precipitation throughout the
weekend.

&&

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

00z Update...

Tonight and Monday...High Confidence.

VFR. Diminishing NW wind becoming light to calm overnight. Sea-
breezes developing along the coast 13-15z, otherwise wind
becoming S 10-15 kt in the afternoon.

Monday night...High confidence in trends.

VFR in the evening, lowering to MVFR-IFR from W to E after 05z.
Scattered showers developing.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Tuesday through Friday/...

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

Tuesday Night: VFR. Breezy.

Wednesday through Thursday Night: VFR.

Friday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Monday...High Confidence.

Small Craft Advisory conditions across most eastern waters, as
well as across the southern outer coastal waters. Winds diminish
late today, but seas will take a little longer to subside below
5 feet. Adjusted the end timing accordingly.

Outlook /Tuesday through Friday/...

Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers.

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

Wednesday through Thursday Night: Winds less than 25 kt.

Friday: Winds less than 25 kt. Slight chance of rain showers.

&&

.FIRE WEATHER...
Special Weather Statement for elevated fire weather concerns
issued for southern New England. A drier air mass filters into
our region behind a cold front. Gusty northwest winds with gusts
up to 35 mph, combined with low relative humidities between 15
and 30 percent could result in fast spread of any fires.
Exercise caution handling any potential ignition sources.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ230-
     256.
     Small Craft Advisory until 10 PM EDT this evening for ANZ231-
     250-251-254-255.

&&

$$

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