Severe Thunderstorm Warning 24, NWS Boston/Norton, MA

585 
WWUS51 KBOX 302320
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
720 PM EDT Tue Jun 30 2026

CTC003-013-MAC013-015-302330-
/O.CAN.KBOX.SV.W.0024.000000T0000Z-260630T2345Z/
Tolland CT-Hartford CT-Hampshire MA-Hampden MA-
720 PM EDT Tue Jun 30 2026

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN TOLLAND...
HARTFORD...SOUTH CENTRAL HAMPSHIRE AND SOUTHEASTERN HAMPDEN COUNTIES
IS CANCELLED...

The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds and
heavy rain are still possible with these thunderstorms.

LAT...LON 4203 7301 4204 7302 4234 7250 4194 7222
      4163 7279 4183 7294 4184 7294 4185 7295
      4189 7294 4190 7291 4197 7289 4197 7303
TIME...MOT...LOC 2313Z 328DEG 25KT 4210 7241 4186 7286 

$$
FT

Area Forecast Discussion
National Weather Service Boston/Norton MA
338 PM EDT Tue Jun 30 2026

.WHAT HAS CHANGED...
The Extreme Heat Watch has been upgraded to an Excessive Heat
Warning for the east slopes of the Berkshires and the South
Coast. A Heat Advisory has been posted for Cape Cod and
Martha's Vineyard.

&&

.KEY MESSAGES...

- Dangerous prolonged heat and humidity Wed through Sat with max
  afternoon heat indices in the 98 to 112 degree range with
  little relief at night. Peak of the heat Thu into Fri.

- A cluster of showers and a few thunderstorms may impact parts
  of our region very late today into tonight. Activity likely
  weakening with main severe weather risk to our northwest, but
  cannot rule out a low risk across western MA/CT.

- W/NW flow aloft may bring a low convective/severe weather risk
  Wed-Fri. However, limited forcing and cap may keep us mainly
  dry. Greatest risk for thunderstorms/severe weather potential
  might wait until Independence Day with the actual cold front.

&&

.DISCUSSION...
KEY MESSAGE 1...Dangerous prolonged heat and humidity Wed
through Sat with max afternoon heat indices in the 98 to 112
degree range with little relief at night. Peak of the heat Thu
into Fri.

High confidence forecast in dangerous prolonged heat and humidity
Wed through Sat. Focused the headline messaging on the peak
threats rather than trying to slice the bologna too thin. Thus,
Extreme Heat Warnings for most of southern New England. Heat
Advisories for the Cape and Vineyard. The peak of this heat
looks to be in the Thursday-Friday time frame.

Heat indices will rise to between 98 and 108 degrees away from
the south coast. The worst of the heat and humidity will likely
be in the CT and Merrimack River valleys. High temperatures will
likely reach between 97 and 103 away from the south coast and
any very localized sea breezes. Heat indices will reach dangerous
levels in the 102 to 113 degree range. It will remain hot and
humid for Independence Day as well. While it may be a few degrees
lower than Thu/Fri, dangerous heat and humidity may continue and
will be determined by the timing of a cold front.

Not only will this be a dangerous prolonged period of heat,
there will be little relief at night. Low temperatures will only
drop into the middle 70s in most locations and 75 to 80 degrees
in the urban centers. In fact, Boston may not drop below 80
degrees during the peak of the heat and humidity!

KEY MESSAGE 2...A cluster of showers and a few thunderstorms may
impact parts of our region very late today into tonight. Activity
likely weakening with main severe weather risk to our northwest,
but cannot rule out a low risk across western MA/CT.

The other concern for late today and especially tonight is a
shortwave that will be dropping southeast in northwest flow aloft
around the developing ring of fire. Effective shear of 30-40 knots
is favorable for this activity to work into our region...but
instability will be rather marginal. So expect a cluster of
weakening scattered showers and perhaps a few thunderstorms to
impact portions of our region. The greatest risk is across western
MA/CT. The overall severe weather threat is low given the limited
instability in our region...but given northwest flow aloft and
lingering momentum can not rule out a low probability for some
severe weather in western MA/CT. However...currently thinking
greatest risk is northwest of our region.

KEY MESSAGE 3...W/NW flow aloft may bring a low convective/severe
weather risk Wed-Fri. However, limited forcing and cap may keep
us mainly dry. Greatest risk for thunderstorms/severe weather
potential might wait until Independence Day with the actual
cold front.

Anomalous heat and humidity will result in rather high instability
across our region Wed through Fri. In addition, a remnant EML
in northwest flow aloft is present. If somehow a few thunderstorms
do develop, they could quickly become severe, even during the
overnight/morning hours. However, a lack of overall synoptic
forcing and a mid level cap should keep this risk low. This
potential will still need to watched. Greatest risk for
convection and potentially some severe weather may wait until
Independence Day when a cold front and stronger forcing arrives.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

Tonight...High confidence.

VFR. Still monitoring a cluster of weakening showers and perhaps
a few TSRA moving SE form Ontario. Greatest risk for this activity
will be across western MA/CT. Not expecting fog to redevelop
towards the south coast, but that will also need to be watched.

Wednesday...High confidence.

Mainly VFR but cannot rule out widely scattered showers/t-storms
later Wed into Wed night. SW winds becoming gusty, especially
towards the Cape and islands.

Wednesday Night...High confidence.

VFR. Gusty SW winds continue.

KBOS Terminal...High Confidence in TAF.

KBDL Terminal...High Confidence in TAF. Showers approach the
terminal 21-23z, with some rumbles of thunder possible around
00z tonight.

Outlook /Thursday through Sunday/...

Thursday through Friday: VFR. Breezy.

Friday Night: VFR.

Independence Day: VFR. Breezy. Chance SHRA, chance TSRA.

Saturday Night through Sunday: VFR. Slight chance SHRA, slight
chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Wednesday Night...High confidence.

Bermuda high pressure will result in a persistent SW flow across
our waters. Winds become gusty tonight and continue into
Wednesday night across the southern waters. In addition, long
southwest fetch should build seas to 3-6 feet across our southern
waters.

Outlook /Thursday through Sunday/...

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.

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

Independence Day: Winds less than 25 kt. Slight chance of rain
showers, slight chance of thunderstorms.

Saturday Night: Winds less than 25 kt. Chance of rain showers,
slight chance of thunderstorms.

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

&&

.CLIMATE...
Record High Temperatures:

July 1:
KBOS: 98/1872
KBDL: 101/1964
KPVD: 97/1964
KORH: 94/1913

July 2:
KBOS: 98/1963
KBDL: 99/1966
KPVD: 98/1941
KORH: 97/1901

July 3:
KBOS: 102/1911
KBDL: 102/1966
KPVD: 98/2002
KORH: 96/1911

July 4:
KBOS: 104/1911
KBDL: 99/1911
KPVD: 99/1919
KORH: 102/1911

Record High Minimum Temperatures:

July 1:
KBOS: 73/1958
KBDL: 73/1968
KPVD: 71/1968
KORH: 72/2018

July 2:
KBOS: 76/2002
KBDL: 73/2018
KPVD: 75/1941
KORH: 73/1963

July 3:
KBOS: 80/2002
KBDL: 73/2018
KPVD: 78/2002
KORH: 72/2002

July 4:
KBOS: 77/2002
KBDL: 74/2018
KPVD: 77/2002
KORH: 73/2018

July 5:
KBOS: 81/1999
KBDL: 77/1999
KPVD: 78/1999
KORH: 73/1999

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ002.
     Air Quality Alert from 11 AM to 11 PM EDT Wednesday for
     CTZ002>004.
     Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
     for CTZ002>004.
MA...Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
     for MAZ002>021-026.
     Heat Advisory from 10 AM Wednesday to 8 PM EDT Saturday for
     MAZ022-023.
RI...Air Quality Alert from 11 AM to 11 PM EDT Wednesday for
     RIZ001>008.
     Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
     for RIZ001>007.
MARINE...Small Craft Advisory from 8 AM to 11 PM EDT Wednesday for
     ANZ231>237.
     Small Craft Advisory from 5 AM Wednesday to 1 AM EDT Friday
     for ANZ254>256.

&&

DISCUSSION...Belk
AVIATION...Belk
MARINE...Belk
CLIMATE...FT

Preliminary Local Storm Report
National Weather Service Boston/Norton MA
637 PM EDT Tue Jun 30 2026

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

0252 PM     Tstm Wnd Dmg     North Amherst           42.42N 72.51W
06/30/2026                   Hampshire          MA   Trained Spotter

            several trees down on Pine St, Bridge St and
            Leverett Rd. Time estimated from radar.

0255 PM     Tstm Wnd Dmg     Amherst                 42.40N 72.50W
06/30/2026                   Hampshire          MA   Law Enforcement

            tree down on North East St. Time estimated
            from radar.

0300 PM     Tstm Wnd Dmg     Belchertown             42.28N 72.38W
06/30/2026                   Hampshire          MA   Law Enforcement

            several trees down on Blue Meadow Road. Time
            estimated from radar.

&&