Flash Flood Warning 8, NWS Boston/Norton, MA

045 
WGUS71 KBOX 031201
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
801 AM EDT Mon Aug 3 2026

MAC017-027-031400-
/O.CON.KBOX.FF.W.0008.000000T0000Z-260803T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex MA-Worcester MA-
801 AM EDT Mon Aug 3 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 AM EDT THIS 
MORNING FOR NORTHERN WORCESTER AND NORTHWESTERN MIDDLESEX COUNTIES...

At 801 AM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2 inches of rain have 
fallen. The expected rainfall rate is 1 to 2 inches in 1 hour. 
Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Lowell, Leominster, Fitchburg, Chelmsford, Dracut, Westford, 
  Gardner, Holden, Athol, Pepperell, Tyngsborough, Groton, 
  Winchendon, Lunenburg, Townsend, Littleton, Lancaster, Templeton, 
  Rutland and Sterling.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4248 7228 4271 7203 4270 7130 4242 7173

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

RM

864 
WGUS71 KBOX 031355
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
955 AM EDT Mon Aug 3 2026

MAC017-027-031405-
/O.EXP.KBOX.FF.W.0008.000000T0000Z-260803T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Middlesex MA-Worcester MA-
955 AM EDT Mon Aug 3 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 10 AM EDT THIS MORNING FOR 
NORTHERN WORCESTER AND NORTHWESTERN MIDDLESEX COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

&&

LAT...LON 4248 7228 4271 7203 4270 7130 4242 7173

$$

RM

Area Forecast Discussion
National Weather Service Boston/Norton MA
214 AM EDT Mon Aug 3 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...

- A cold front brings the return of heavy rain and gusty winds
Sunday night and Monday. Localized flash flooding possible.

- After a quiet Tuesday unsettled weather returns mid week through
the weekend with periods of showers and storms.

&&

.DISCUSSION...

KEY MESSAGE 1...A cold front brings the return of heavy rain and
gusty winds Monday.

An anomalously deep upper trough digging into the Ohio Valley will
become cutoff as the broader longwave trough axis works its way
slowly east. Its trough axis will cross over southern New England
Monday night into Tuesday ushering in a much quiet and drier period.
Before that, however, we'll be dealing with a very moist and dynamic
system for the next 18-24 hours. This, as the shortwave and surface
reflection pull copious amounts of moisture north into New England
on strengthening SW flow (PWATs 2+ inches) with a 40-55 kt LLJ
strengthening as it's core moves over the Cape and islands.
Fortunately, even though BUFKIT soundings show 55kts down to about
925mb, the low level inversion should keep the worst aloft.
Regardless, it will be a gusty day, especially over southeast MA.
While some brief stronger gusts can't be ruled out, they are more
than likely to top out around 40 mph on Cape Cod.

Regardless of its impact at the surface, said LLJ will certainly act
as a strong forcing mechanism for our heavy rain. This together with
divergence aloft/placement beneath the RRQ of an upper jet will lead
to broad, deep layer ascent and widespread rain showers and
thunderstorms. Continuing to expect an initial round of moderate to
heavy rain showers this morning into the afternoon which has already
begun to materialize. The atmosphere is primed for some heavy
downpours and while we can't nail down exactly who will see these
downpours, any convection would lead to a better chance of those
higher rain rates hinted at by the HREF (low probability of as much
as 1+/hr).

There's unlikely to be a real break in the showers and embedded
thunderstorms but any pockets of clearing skies between showers may
lead to increased instability parameters and a better chance for one
of these thunderstorms to become severe as a final source of forcing
arrives in the evening in the form of a cold front. Any storms that
do get going will be in an environment with 30-45 kts of 0-6km bulk
shear meaning potential for organization and some damaging wind
potential.

When all is said and done (ending in western MA by 8pm, eastern MA
by midnight) a widespread 0.5 to 1.5 inches of rain is expected.
That being said, convective enhancement and potential for training
thanks to boundary-parallel mean flow mean that localized areas
could see significantly more, on the order of 3-4 inches. This
amount, especially if it falls in a short period, may lead to street
flooding and even isolated flash flooding situations. However, we
don't expect a widespread flash flooding risk with this system.

KEY MESSAGE 2...After a quiet Tuesday unsettled weather returns mid
week through the weekend with periods of showers and storms.

After a beautiful, mostly sunny, less humid day on Tuesday under
high pressure ridging, unsettled weather returns Wednesday into the
weekend. A broad mid level trough sets up over the eastern U.S. with
several shortwaves rotating through the base of the broader trough
and this will bring periodic rain and thunderstorm chances each day,
especially in the afternoon/evening.

&&

.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:

Through 12Z: Moderate confidence.

IFR/LIFR cigs continue to push north. Scattered -SHRA will
expand east through 12z. Embedded thunder is possible, but low
probability. LLJ pushes in from the south leading to added
added wind shear in the Cape terminals, BOS, and PVD.

Monday: Moderate confidence.

IFR/LIFR in RA/+RA through the day. Embedded storms possible
within the first few rounds of rain 12-21Z. Another round of
scattered thunderstorms likely pushes through from west to east
19Z-02Z ahead of the approaching cold front. Wind shear likely
continues in the east/southeast terminals during the day. SW
winds 10-20 kts with gusts 20-30 kts. Could see period in the
afternoon that winds gust 25-35 kts for the east and especially
SE terminals if we clear out before the early evening round of
storms.

Monday night: High confidence.

SHRA/TSRA will be pushing out of eastern terminals by 04Z
leaving VFR conditions with light W wind.

Tuesday: High confidence.

VFR. Winds 5-10 kts, first W then becoming SW after 18Z.

KBOS Terminal...Moderate confidence in TAF.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Tuesday through Friday/...

Tuesday through Tuesday Night: VFR.

Wednesday through Wednesday Night: VFR. Slight chance SHRA.

Thursday through Thursday Night: VFR. Breezy. Slight chance
SHRA, slight chance TSRA.

Friday: VFR. Breezy. Chance SHRA, chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Winds and seas increase into early this morning across the
southern and eastern waters eventually increasing across the
northern waters. Seas 5-9 ft for the outer coastal waters,
especially south. 5-7 ft seas stretch into portions of the inner
souther waters. SW winds 15-20 kts with gusts around 30 kts.
Can't rule out a few isolated gusts near Gale-force late
morning-afternoon if winds mix down from the low level jet
overhead. SCAs are in effect for all the coastal marine zones.
Elevated seas will keep SCAs around through Tuesday for the
southern waters.

A high surf advisory is in effect for the south coast and
islands Tuesday. A strong 35-45 kt southerly low level jet will
help build waves 5-9 ft across the waters of RI and south of
MVY-ACK Monday. Rough surf and strong rips are likely to linger
into Tuesday. Will have to watch this as Tuesday is shaping up
to be an ideal beach day.

Outlook /Tuesday through Friday/...

Tuesday: Winds less than 25 kt. Seas up to 5 ft.

Tuesday Night: Winds less than 25 kt. Areas of seas approaching
5 ft.

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

Wednesday Night: Winds less than 25 kt.

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

Thursday Night through Friday: Winds less than 25 kt. Areas of
seas approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory from 7 AM this morning to 9 PM EDT this
     evening for MAZ023-024.
RI...High Surf Advisory from 7 AM this morning to 9 PM EDT this
     evening for RIZ006>008.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for ANZ230-
     236.
     Small Craft Advisory from 8 AM this morning to 5 PM EDT this
     afternoon for ANZ231-251.
     Small Craft Advisory from 8 AM this morning to 2 AM EDT
     Tuesday for ANZ232>234.
     Small Craft Advisory until 2 PM EDT Tuesday for ANZ235-237.
     Small Craft Advisory from 8 AM this morning to 2 PM EDT
     Tuesday for ANZ250-254.
     Small Craft Advisory until 8 PM EDT Tuesday for ANZ255-256.

&&

DISCUSSION...BW
AVIATION...BW
MARINE...BW

Preliminary Local Storm Report
National Weather Service Boston/Norton MA
644 AM EDT Mon Aug 3 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0625 AM     Flash Flood      2 N Agawam              42.10N 72.60W
08/03/2026                   Hampden            MA   Fire Department/R

            In West Springfield, Rt 5 was closed from
            the north end bridge to memorial bridge due
            to both underpasses flooded to 2+ feet
            depth. Relayed by amateur radio.

&&