495
FXUS61 KBOX 262334
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
734 PM EDT Sat Jul 26 2025
.SYNOPSIS...
A cluster of showers and a few embedded thunderstorms cross the
region on Sunday with the activity most widespread across western
and northern Massachusetts. Heat and humidity return Monday and
especially Tuesday when Heat Indices may approach 100 degrees in
some locations. Dry weather dominates much of next week outside the
risk for a few spot showers/thunderstorms. Much cooler/less humid
air follows behind a cold front late next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Messages...
* Dry & pleasant tonight with lows in the upper 50s to the middle 60s
* A bit of smoke/haze lingers especially across the interior
Details...
Tonight...
A ridge of high pressure slowly moves east of the region tonight. It
still will provide a dry/tranquil night for southern New
England...despite a gradual increase in cloud cover from the west
overnight. Low temps probably bottom out in the upper 50s to the
middle 60s with the coolest readings across southeast MA/Cape given
pattern recognition with departing high pressure.
The HRRR/RAP do indicate some lingering smoke tonight...but it will
be gradually dissipating and the bulk of it will be shifting into
the interior.
Lastly...a shortwave/mid level warm front will be approaching from
the west near daybreak. It will generate a burst of elevated
instability...so a cluster of showers and perhaps a few embedded t-
storms will approach western MA/CT but probably not until near or
after daybreak.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Key Messages...
* Cluster of showers & few embedded t-storms on Sunday with the
greatest areal coverage north of the CT/RI/MA borders
* Pockets of heavy rain possible Sun with best chance for that
across northwest/north central MA
* Clouds & some showers hold Sunday highs mainly in the middle to
upper 70s with a few spots around 80
Details...
Sunday...
An approaching mid level warm front/burst of elevated instability
will work across the region on Sunday. This will generate a cluster
of showers and perhaps a few embedded t-storms that will move across
the region. This activity may impact the entire region...but it
appears the activity will be most numerous north of the CT/RI/MA
border and especially northwest and north central MA. This is where
the guidance has the best forcing. There certainly could be
downpours with locally heavy rainfall given Pwats near 2 inches. As
for the timing...the bulk of the activity looks to occur Sun morning
into the mid afternoon with the focus across our northern zones.
Still a few showers and a rumble or two of thunder possible later in
the day...but think the bulk of the activity occurs through mid
afternoon. High temps will mainly be in the middle to upper 70s with
a few spots near 80 given the clouds and some showers.
Sunday night...
Bulk of any lingering showers near the Cape/Islands depart early
Sunday evening. Otherwise...partial clearing expected and with the
wet ground/increasing low level moisture patchy fog may develop.
Overnight low temps will be mainly in the 60s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Messages...
* Heat Advisory in effect from 11 AM Monday to 8 PM Tuesday.
* Mostly dry this week with a chance of showers and t-storms Wed/Thu.
* Cooler for the second half of the week.
Starting the week off hot... ensemble and deterministic guidance
continue to indicate 850mb temps between 18-20C and 925mb temps
between 25-27C. Surface temps will likely be in the high 80s to mid
90s Monday and mid to high 90s Tuesday. Dewpoints will also hover in
the high 60s to lower 70s both days, leading to "Feels Like"
temperatures to range from upper 90s to mid 100s. While Monday will
be hot, especially after the relatively cooler temperatures on
Sunday, the highest temperatures and heat impacts will be on
Tuesday. There is also the chance that the high temperatures and
humidity will stick around into Wednesday; however, model guidance
is about equally split, and confidence is not quite there. Given the
multi-day impacts and after collaboration with neighboring offices,
felt confident moving forward with Heat Advisory for Monday and
Tuesday.
A weak mid-level shortwave is still on track to move through
sometime on Tuesday, bringing the chance for isolated to scattered
showers and thunderstorms in the afternoon/evening. Ensemble
guidance shows a more substantial wave moving through sometime in
the Weds-Thurs timeframe. Still quite a bit of uncertainty in the
details such as timing, precipitation chances/amounts. Expecting a
much cooler (and drier) airmass to push into southern New England
once the shortwave moves through, allowing for a break in the high
heat and humidity. Ensemble guidance shows good agreement with a
transition to even below normal temperatures by Friday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update...
Tonight...High confidence.
Mainly VFR conditions persist tonight...but some lingering
smoke/haze may result in some lower vsbys at times across the
interior. Winds becoming SW generally under 10 knots.
Sunday...Moderate confidence.
A cluster of showers and perhaps a few embedded t-storms works
across the region from west to east during the morning and
afternoon. The areal coverage/intensity looks to be greatest across
northwest/north central MA with less as you move southeast. VFR
conditions will be mixed with MVFR cigs/vsbys at times in showers
and perhaps some IFR conditions in heavier showers. S winds 5-10
knots.
Sunday night...Low confidence.
A wide variety of conditions possible Sun night. Cigs may improve or
temporarily improve to mainly VFR...but this may allow low clouds
and fog patches to develop. There also may be low clouds towards the
Cape and Islands. Light SW may shift to the NW by daybreak Mon.
KBOS terminal...High confidence in TAF.
KBDL terminal...High confidence in TAF.
Outlook /Monday through Thursday/...
Monday through Wednesday: VFR.
Wednesday Night: VFR. Chance SHRA, slight chance TSRA.
Thursday: Chance SHRA, slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Sunday night...High confidence.
High pressure shifts east of the waters tonight as a mid level warm
front crosses the region Sun. The pressure gradient will remain weak
enough to keep winds/seas below small craft advisory thresholds. We
will have to watch for areas of fog to develop across the southern
waters Sun night.
Outlook /Monday through Thursday/...
Monday through Wednesday: Winds less than 25 kt.
Wednesday Night through Thursday: Winds less than 25 kt. Chance
of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from 11 AM Monday to 8 PM EDT Tuesday for
CTZ002>004.
MA...Heat Advisory from 11 AM Monday to 8 PM EDT Tuesday for
MAZ003>007-010>019-026.
Air Quality Alert until 11 PM EDT this evening for MAZ002>024-
026.
RI...Heat Advisory from 11 AM Monday to 8 PM EDT Tuesday for
RIZ001>004.
Air Quality Alert until midnight EDT tonight for RIZ001>008.
MARINE...None.
&&
$$
SYNOPSIS...Frank
NEAR TERM...Frank
SHORT TERM...Frank
LONG TERM...Loconto/McMinn
AVIATION...Frank/Loconto/McMinn
MARINE...Frank/Loconto/McMinn