187
FXUS61 KBOX 042339
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
739 PM EDT Wed Jun 4 2025

.SYNOPSIS...
Summer warmth Thursday and Friday with the heat peaking on
Thursday as highs reach 90 to 95 away from the immediate coast.
While an isolated shower/thunderstorm will be possible Thursday,
there will be a much better chance of scattered showers and
thunderstorms Friday some of which may linger into Saturday.
Unsettled weekend once again across southern New England.
Chances for showers and thunderstorms are highest Friday
evening. Drier conditions expected Monday before more showers
are possible heading into midweek next week. High temperatures
remain primarily in the 70s and 80s across the region.

&&

.NEAR TERM /THROUGH THURSDAY/...
Key Messages...

*  Mild night with increasing humidity

Details...

Upper level ridging remains in control of our weather tonight.
Humidity values increase overnight with southwesterly flow. Low
temperatures will remain mild with lows falling to 60-65 degrees,
especially in urban areas.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH 6 PM THURSDAY/...
Key Messages...

* Hot Thu with highs 90-95 away from the immediate coast
* Low chance of showers and some isolated thunderstorms across NW MA
* Little relief from the hot and humid conditions Thursday night

Details...

Thursday...

Still expecting widespread heat Thursday as a strong upper level
ridge builds over Southern New England. The ridge will result in
plenty of sunshine with 925T rising to between +23C and +25C!
Expecting temperatures to quickly warm into the lower and mid 70s
Thursday morning with the onset of mixing. Hot conditions develop by
the afternoon with high temperatures reaching between 90 and 95 in
many locations away from the immediate coast. Urban areas will have
the greatest chance of seeing 95 degree readings. There also will be
a bit of humidity to the air with dewpoints in the lower to middle
60s. Heat Index Values will climb into the lower to middle 90s in
many locations. While we are not anticipating any heat
headlines...our experimental NWS Heat Risk product indicates
moderate impacts for most individuals sensitive to the heat.

While mainly dry and hot weather will be the story on Thu we can not
rule out isolated showers/t-storm or two. Expecting somewhat high
CAPE values but the lack of forcing and a deep dry layer aloft
should prevent widespread thunderstorms. The best chance will be on
any subtle sea breeze boundaries or some terrain impacts/elevated
heating. Again though if any activity is able to develop it will be
isolated/localized with the most locales remaining dry.

Thursday Night...

Another warm and muggy night expected Thursday night with many
locations seeing low temperatures in the middle and upper 60`s to
near 70. Could see a few showers or perhaps a thunderstorm across
western areas as any remnant convection from a frontal boundary to
the NW makes its way east through the first half of the overnight.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Key Messages:

* Chances for showers and thunderstorms Friday through Sunday, with
  the highest chances Friday night

* Briefly dry on Monday before rain chances return Tuesday

* Highs mostly in the upper 70s and low 80s through this period,
  aside from Saturday

Details...

Friday evening looks to have the best chances for showers and some
thunderstorms. The latest NAM indicates surface CAPE values ranging
from 1500 J/kg to close to 3000 J/kg in some spots across the
interior in the afternoon hours, although its worth noting that the
flow aloft is quite weak and there is not much shear. As time goes
on and CAPE decreases, the chance for some heavy downpours may
increase. Ensemble means indicate PWAT values by Friday afternoon
getting close to 1.6", with the ECMWF ENS showing pockets of these
elevated PWAT values in western and eastern MA. Generally, NAEFS
guidance has PWAT values just under 2 standard deviations above
normal across the whole region, which is in agreement across the
other ensembles. Latest deterministic guidance has not completely
nailed down one area that could see elevated precipitation values,
but this should resolve as the event gets closer.

Through the weekend, the chance for showers remains. Some guidance
is hinting at a brief dry period Sunday heading into Monday,
particularly as weak high pressure builds in Monday, but there`s
higher confidence in a drier Monday than sometime Sunday at this
time. Rain chances and elevated surface moisture make a return
Tuesday through Wednesday morning with the weakening of Monday`s
high pressure and rain associated with a frontal passage from a low
moving NE across Canada.

In terms of temperatures, highs across southern New England are
expected to remain in the upper 70s and low to mid 80s across the
period, aside from Saturday when highs decrease a bit to the lower
70s in some spots and generally may remain below 80. Lows are
expected to generally be in the 50s and 60s.

&&

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

00z TAF Update...

Through Tonight...High confidence.

VFR. Winds become light to calm overnight. Some terminals that
tend to see some fog could go MVFR tonight, namely BAF and ACK,
but it`s not expected to last very long.

Tomorrow into Tomorrow Night...High confidence.

VFR. SW winds 5-10 kts across southern New England with late
morning seabreezes at coastal terminals around 15z. Very low
risk for isolated showers/thunderstorms in the afternoon,
primarily in NW MA.

BOS TAF...High confidence in TAF.

BDL TAF...High confidence in TAF.

Outlook /Thursday Night through Monday/...

Thursday Night: VFR. Breezy. Slight chance SHRA.

Friday: Mainly VFR, with local MVFR possible. Chance SHRA,
chance TSRA.

Friday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, slight chance TSRA.

Saturday: Mainly VFR, with areas MVFR possible. SHRA likely,
slight chance TSRA.

Saturday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.

Sunday: VFR. Chance SHRA.

Sunday Night through Monday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today through Thursday...High confidence.

Upper level riding persists and keeps conditions below small craft
advisory overnight through Thursday. Breezier southwest winds
develop Thursday night and Friday which could lead to some choppy
seas.

Outlook /Thursday Night through Monday/...

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

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

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

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ002>004.
MA...Air Quality Alert until 11 PM EDT this evening for MAZ009-011.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...Hrencecin/FT
NEAR TERM...FT
SHORT TERM...FT
LONG TERM...Hrencecin
AVIATION...Hrencecin/FT
MARINE...Hrencecin/FT