Boston, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

006
FXUS61 KBOX 040702
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
302 AM EDT Mon May 4 2026

.WHAT HAS CHANGED...
No changes with the latest forecast update.

&&

.KEY MESSAGES...

- Breezy, warm, and dry day with elevated fire weather potential
this afternoon.

- Warmer on Tuesday with a chance for showers and thunderstorms
across far northwestern Massachusetts.

- Unsettled for the midweek timeframe with multiple chances for
showers and embedded thunderstorms.

- Turning sharply cooler late in the week and into the weekend.

&&

.DISCUSSION...
.DISCUSSION...

KEY MESSAGE 1... Breezy, warm, and dry day with elevated fire
weather potential this afternoon.

Cold start this morning for many of us as a few additional hours of
radiational cooling took place with less cloud cover than high-res
guidance initially advertised. Coldest spots this morning are
interior valleys with lows in the lower 30s. Quick warm up this
morning as 850mb temps soar from 0C to +6C by this afternoon. Given
the expected well mixed boundary layer up to 800mb with full sun,
expecting high temperatures in the upper 60s to low 70s in the CT
and Merrimack River Valleys. Coolest temps will be found along the
immediate south coast will be coolest in the low to mid 60s. Good
mixing also leads to a gusty day; with a 25-35kt 850mb jet overhead,
expecting to mix down gusts of 25 to 35 mph. This, combined with the
drier air (RH values down to 25-30 percent) has led us to issue a
Special Weather Statement for elevated fire weather potential
covering all of southern New England with the exception of Cape Cod
and the islands.

KEY MESSAGE 2... Warmer on Tuesday with a chance for showers and
thunderstorms across far northwestern Massachusetts.

Cold front slowly advances toward our CWA through the day on
Tuesday. At the same time, high pressure continues to build over the
Atlantic. The result will be a gusty SW winds and even warmer
temperatures away from the marine modified airmass towards the south
coast. 925T on the order of +17C/+18C should allow highs to reach
near 80 in the lower elevations northwest of I-95. The gusty
southwest winds will hold highs in the 60s near the south coast,
Cape and Islands. It is possible that Nantucket does not even break
60 degrees! Bufkit soundings support southwest wind gusts of 25 to
35 mph with a few gusts of 40-45 mph possible towards the upper Cape.

Mainly dry weather prevails Tue as most of the synoptic scale
forcing will remain well to our west in the vicinity of the cold
front. Still see at least a low risk for a thunderstorm or two
across western Massachusetts with CAPE values increasing to around
1000 J/kg Tuesday afternoon.

KEY MESSAGE 3...Unsettled for the midweek timeframe with multiple
chances for showers and embedded thunderstorms.

A slow moving cold front approaches the region from the west on Wed.
Still some timing differences...But we do expect a band of showers
to overspread the region from west to east as the day wears along.
This may take until mid-late afternoon to reach the I-95
corridor...but again the timing still needs to be worked out. There
might be an embedded t-storm or two as well...But instability does
not look to be high enough for any severe weather.

This cold front slowly sags south of our region Wed night into Thu
bringing cooler temps. In terms of the potential for a secondary
area of low pressure, the trend amongst guidance has been for a
solution further to the south of the CWA and thus more of a glancing
blow.  The exact track of this low will have a significant impact on
temperatures during the day Thu depending on if we see rain or end
up mainly dry.

KEY MESSAGE 4...Turning sharply cooler late in the week and into the
weekend.

The long range ensembles are in good agreement in an upper trough
with below normal height fields re-establishing itself Fri into the
weekend. Modest westerly flow this time of year coupled with the
strong May sun angle should keep high temps near or just slightly
below normal though. Highs should still mainly be in the 60s. The
night/s will be potentially cool though with lows in the 40s and
potentially some 30s along with a frost risk if we have enough
clearing.

As for precipitation chances...some shortwave energy with the
associated upper trough/cold pool aloft may bring the potential for
a few showers at times. However...not expecting a washout with
plenty of dry weather expected as well over this time.&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

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

06z TAF Update...

VFR conditions continue through the next day. SW winds increase
later this morning and especially in the afternoon with gusts
on the order of 25 to 35 knots with perhaps a few gusts near 40
knots towards the typically prone locations near KFMH. The gusts
gradually diminish this evening...but still expect sustained
S-SW winds of 5 to 15 knots overnight with a few gusts up to 20
knots persisting.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday Night through Friday/...

Tuesday Night: VFR. Breezy. Slight chance SHRA.

Wednesday through Wednesday Night: Mainly VFR, with local IFR
possible. Breezy. Chance SHRA.

Thursday: VFR. Chance SHRA.

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

Friday: VFR. Breezy. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence.

Through Tuesday...

Southwest winds today gusting 25-30 kts. Will also see seas
build to 4-6 feet across the outer waters . Given these
conditions, the Small Craft Advisory has been extended into
Tuesday for the outer waters and expanded into the inner waters
this afternoon. There is also a chance for near-gale force winds
across Buzzard`s Bay as well as Nantucket Sound this afternoon.
Additional SCAs will likely be needed Tuesday.

Outlook /Tuesday Night through Friday/...

Tuesday Night: Moderate risk for Small Craft Advisory winds
with local gusts up to 30 kt. Rough seas up to 9 ft.

Wednesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Chance of rain showers.

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. Chance of rain showers,
slight chance of thunderstorms.

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

Thursday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain showers.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 11 AM this morning to 8 PM EDT this
     evening for ANZ230>237-251.
     Small Craft Advisory until 8 AM EDT Tuesday for ANZ250-254>256.

&&

$$

DISCUSSION...FT
AVIATION...FT
MARINE...FT