Somerville, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

443
FXUS61 KBOX 061118
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
718 AM EDT Sun Jul 6 2025

.SYNOPSIS...
Higher than normal heat and humidity expected today and Monday with
a Heat Advisory in place. Unsettled weather makes a return Monday
into Monday night, continuing off and on through much of next week.
Cooler weather expected middle to late next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages...

* Hotter today with more humidity.

Mid level heights rise initially today as the 500 mb ridge axis
shifts east across New England. This begins to turn the low/mid
level flow out of the SW while at the surface warm, moist flow is
already in place. This will further pump up the heat and humidity
today, pushing high temperatures into the mid 90s (80s closer to the
south coast). Dewpoints rising from the 50s into the upper 60s will
make it feel much more humid today as well. This heat continues into
Monday, so a Heat Advisory is in effect for the extended period of
abnormally warm and humid conditions. The one factor working to make
it feel a bit better will be the increasingly gusty winds as we are
sandwiched between low pressure over the Great Lakes and high
pressure over the Atlantic. Winds gusts up to 20-25 mph are
expected. Sun will be filtered by high clouds early on, though they
will diminish through the day. Tonight, dry and mild conditions
expected.

&&

.SHORT TERM /MONDAY/...
Key Messages...

* Heat and humidity peaks.

* Shower and thunderstorm chances increase.

Zonal flow to start the week becomes a bit more amplified as we move
further into the weak, with late Monday being a transition from the
heat and humidity of the late weekend back into unsettled weather.
One last day of abnormally hot temperatures for Monday before an
increase in cloudcover and rain chances leads to  a cooler day on
Tuesday. Mostly dry with increasing cloudcover, but guidance has
been quicker to bring in rain and thunderstorm chances ahead of an
approaching cold front, as early as Monday afternoon. EPS ensembles
have increased probabilities of measurable rain quite a bit on
Monday while GEFS also indicates a >50% chance in the interior.
Expect that any thunderstorms will be garden variety (sub severe),
lacking any bulk shear and with poor mid level lapse rates. Moisture
will be abundant, though, with 70s dewpoints sticking around and
PWATs near 2 inches. Any storms may contain heavy downpours.

&&

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

* Periodic chances of unsettled weather each day.

* Seasonable to even slightly cooler than average temps by late
  week.

A series of shortwaves moves through the largely zonal flow through
the end of the week while Monday night`s cold front stalls around
the coastal plain Tuesday night and moves offshore by Thursday. This
will provide a source of lift in addition to the mid level shortwave
moving through Tue into Wednesday. Details are sparse but
thunderstorms with heavy rain are possible on Tuesday into
early Wednesday followed by another shortwave Thursday into Friday.

&&

.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

12Z update...

Today...High confidence.

VFR. SSW to SW winds 10 to 15 knots. Gusting 20 to 25 knots by
late morning to early afternoon.

Tonight...Moderate confidence.

VFR, areas of MVFR/IFR develop mainly south of I-90 mainly after
09z. Patchy fog develops across the south coast. SSW to SW wind
with speeds 10 to 15 knots.

Monday...Moderate confidence.

Generally VFR north with MVFR to IFR along the south coast of RI
and MA. Hit-or-miss SHRA and TSRA during the afternoon and
evening. SSW to SW winds 10 to 15 knots. Gusting 20 to 25 knots by
late morning to early afternoon.

KBOS Terminal...High confidence in TAF.

Confidence in TAF is high through 12z Monday, VFR with gusty SSW
to SW wind with gusts 20 to 25 knots. But forecast confidence is
moderate beyond 12z Monday with the potential for lower ceilings
and SHRA/TSRA possible Monday afternoon and evening.

KBDL Terminal...High confidence in TAF.

Confidence in TAF is high through 12z Monday, VFR with gusty SSW
to SW wind with gusts 20 knots. But forecast confidence is
moderate beyond 10z Monday with the potential for lower ceilings
and SHRA/TSRA possible Monday afternoon and evening.

Outlook /Monday Night through Thursday/...

Monday Night: VFR. Breezy. Chance SHRA, slight chance TSRA.

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

Tuesday Night: Mainly VFR, with local IFR possible. Chance
SHRA, slight chance TSRA.

Wednesday through Thursday: Mainly VFR, with local IFR
possible. Slight chance SHRA, slight chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through tonight: High confidence.

SW winds increase today, gusting 20-25 kts, as high as 30 kts on
eastern waters. Seas 3-5 ft. Most zones will stay shy of SCA
criteria except the northern outer waters with gusts 25-30 kts in
the afternoon and sea 4-5 ft. SCA will be in effect for that zone
from 18z today through 06z Mon.

Monday: High confidence.

SW winds 10-15 kts with gusts 20-25 kts on southern waters, 25-30
kts on the eastern waters. Seas 2-3 ft, increasing to 2-4 ft on the
outer waters late in the day.

Outlook /Monday Night through Thursday/...

Monday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain showers, slight chance of thunderstorms.

Tuesday through Tuesday Night: Winds less than 25 kt. Areas of
seas approaching 5 ft. Chance of rain showers, chance of
thunderstorms.

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

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Monday for CTZ002>004.
MA...Heat Advisory until 8 PM EDT Monday for MAZ003>007-010>019-026.
RI...Heat Advisory until 8 PM EDT Monday for RIZ001>004.
MARINE...Small Craft Advisory from 2 PM this afternoon to 2 AM EDT
     Monday for ANZ250.

&&

$$

SYNOPSIS...BW
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...BW
AVIATION...BW/Dooley
MARINE...BW