Alert archive / Connecticut / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 33, NWS Boston/Norton, MA

July 4, 2026Capitol Planning Region, Connecticut

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 4, 2026, 8:18 PM EDT for Capitol Planning Region, Connecticut. It was in force for 46 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 4, 2026, 8:18 PM EDT (00:18 UTC)
Expired: Jul 4, 2026, 9:04 PM EDT
In force: 46 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Capitol Planning Region, CT

The radar

The Brookhaven radar (KOKX), 93 km from the middle of the area, began a volume at 00:19 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Jul 4, 8:40 PM EDT	TSTM WND DMG	Bristol, CT	In Bristol, multiple power lines down across town. Relayed via Amateur Radio.
Jul 4, 8:40 PM EDT	TSTM WND DMG	Southington, CT	In Southington, multiple trees reported down on I-84. Relayed via Amateur Radio.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this severe thunderstorm warning; the first came 22 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 4, 7:20 PM EDT	Severe Thunderstorm Watch	SPC	3 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 0.3 hours before the alert went out and 93 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1105 J/kg
Mixed-layer CIN: -28 J/kg
Mixed-layer LCL: 1723 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 100 m²/s²
0-3 km storm-relative helicity: 144 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

832 
WUUS51 KBOX 050018
SVRBOX
CTC003-050115-
/O.NEW.KBOX.SV.W.0033.260705T0018Z-260705T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
818 PM EDT Sat Jul 4 2026

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Southwestern Hartford County in northern Connecticut...

* Until 915 PM EDT.

* At 818 PM EDT, severe thunderstorms were located along a line
  extending from Winsted to Northwest Harwinton to near Oakville to
  near Southbury to near Redding, moving southeast at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines.

* Locations impacted include...
  Hartford, New Britain, West Hartford, Bristol, East Hartford,
  Southington, Newington, Windsor, Wethersfield, Farmington,
  Simsbury, Bloomfield, Berlin, Rocky Hill, Avon, Plainville, Windsor
  Locks, Granby, Canton, and Burlington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Boston/Norton.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4181 7295 4189 7294 4190 7291 4193 7290
      4191 7265 4163 7266 4163 7271 4160 7272
      4155 7282 4157 7285 4155 7285 4156 7288
      4156 7295 4163 7293 4164 7294 4164 7299
      4180 7302
TIME...MOT...LOC 0018Z 293DEG 37KT 4194 7309 4180 7306 4157 7312 4145
7320 4132 7334

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Legro

2 follow-up statements

514 
WWUS51 KBOX 050051
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
851 PM EDT Sat Jul 4 2026

CTC003-050115-
/O.CON.KBOX.SV.W.0033.000000T0000Z-260705T0115Z/
Hartford CT-
851 PM EDT Sat Jul 4 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM EDT
FOR SOUTHWESTERN HARTFORD COUNTY...

At 851 PM EDT, severe thunderstorms were located along a line
extending from near Bloomfield to Rocky Hill to near Durham to near
Branford to 6 miles east of Milford, moving southeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines.

Locations impacted include...
Hartford, New Britain, West Hartford, Bristol, East Hartford,
Southington, Newington, Wethersfield, Farmington, Berlin, Rocky Hill,
Avon, Plainville, and Burlington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Boston/Norton.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4163 7266 4163 7271 4160 7272 4155 7282
      4157 7285 4155 7285 4156 7288 4156 7295
      4163 7293 4164 7294 4164 7299 4181 7297
      4181 7296 4178 7265
TIME...MOT...LOC 0051Z 293DEG 37KT 4181 7269 4167 7267 4144 7273 4132
7281 4119 7295

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Legro

545 
WWUS51 KBOX 050104
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
904 PM EDT Sat Jul 4 2026

CTC003-050114-
/O.CAN.KBOX.SV.W.0033.000000T0000Z-260705T0115Z/
Hartford CT-
904 PM EDT Sat Jul 4 2026

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN HARTFORD COUNTY
IS CANCELLED...

The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled.  However gusty winds and
heavy rain are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 100 AM EDT for
northern Connecticut.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Boston/Norton.

LAT...LON 4163 7266 4163 7271 4160 7272 4155 7282
      4157 7285 4155 7285 4156 7288 4156 7295
      4163 7293 4164 7294 4164 7299 4181 7297
      4181 7296 4178 7265
TIME...MOT...LOC 0059Z 293DEG 37KT 4178 7258 4164 7256 4141 7262 4129
7270 4116 7284

$$

Legro

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Boston/Norton, MA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 4, 7:15 PM EDT, 1 hour 3 minutes earlier. Its key messages:

Significant heat and humidity continues for the rest of this afternoon and evening. Scattered showers and thunderstorms possible through the evening. A storm or two may produce strong to damaging wind gusts.
Cooler temperatures are forecast for the first half of the week. Temperatures have the potential to be much cooler as a soaking rain is becoming more likely in the late Sunday through Tuesday time frame.

Area forecast discussion, Jul 4, 7:15 PM EDT, 1 hour 3 minutes before

Area Forecast Discussion
National Weather Service Boston/Norton MA
715 PM EDT Sat Jul 4 2026

.WHAT HAS CHANGED...
No significant changes with this forecast update.

&&

.KEY MESSAGES...

- Significant heat and humidity continues for the rest of this
  afternoon and evening. Scattered showers and thunderstorms
  possible through the evening. A storm or two may produce
  strong to damaging wind gusts.

- Cooler temperatures are forecast for the first half of the
  week. Temperatures have the potential to be much cooler as a
  soaking rain is becoming more likely in the late Sunday
  through Tuesday time frame.

&&

.DISCUSSION...
KEY MESSAGE 1...Significant heat and humidity continues for the
rest of this afternoon and evening. Scattered showers and
thunderstorms possible through the evening. A storm or two may
produce strong to damaging wind gusts.

Hot and humid conditions ongoing across southern New England,
with temperatures and heat indices alike well into the mid-to-
upper 90s. Heat Advisory in effect for northern CT, majority of
MA, and RI until 8 PM EDT this evening.

Elsewhere, convection is continuing across upstate NY and
central/south VT. This activity is trying to "split the gap"
between southern MA/northern CT/RI and northeastern MA. The
northeastern MA solution is winning at the moment, with a
cluster of storms crossing over into parts of Essex County as of
2:45 PM EDT.

High-resolution guidance has been rather ugly in trying to
picture how the rest of this afternoon and evening unfolds.
Overall, ultimately think that this splits up into two different
"events" (such that they are): this afternoon between now and
5-6 PM, and another between 8-11 PM. Firework shows this evening
could be dicey at times, particularly for eastern MA. Showers
and storms move offshore by 2 AM EDT at the latest.

Cold front due before sunrise Sunday morning, where a wind shift
from the NNE will kick in, veering to the ENE throughout the
day. Highs much more reasonable in the low-to-mid 80s.

KEY MESSAGE 2...Cooler temperatures are forecast for the first
half of the week. Temperatures have the potential to be much
cooler as a soaking rain is becoming more likely in the late
Sunday through Tuesday time frame.

High confidence remains that temps will cool down and return to
more seasonable summer readings thru next week. For starters
850 mb temps are forecast to cool to between +12 to +15C. That
will be enough to get temps back into the 80s on its own.
Dewpoints are also forecast to cool down as well, which will
make things feel more comfortable than it has been.

Temps may also be much cooler if we can get substantial cloud
cover and rain into the forecast area. Overnight guidance has
doubled the number of ensemble members with more than 1 inch of
QPF. Now nearly all of the ECMWF ensemble members are in that
camp around BDL, with roughly half of members greater than 1
inch as you move northeast to BOS. However the GEFS has also
moved on board with roughly half of all members at or above 1
inch QPF across southern New England. Deterministic model
guidance is forecasting mid level warm advection to produce an
area of frontogenesis, giving this a little more synoptic
support for rainfall than the more typical scattered summertime
convective pattern to rainfall. NBM PoP looks pretty good at
this range, with categorical across the southwestern forecast
area and likely farther northeast, given the timing uncertainty.
Rain could begin as early as late Sun night and continue thru
Tue. Right now 6 hr FFG across much of the forecast area is at
least 3 inches, so I am not anticipating flooding unless we see
guidance really start to ramp up QPF numbers.

&&

.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...

Today through Sunday...High confidence.

VFR conditions dominate through Sunday except during any TSRA.
Storms should move off the northeastern shore by 01-02z, but
moving into western CT/MA 00-02z. Storms should move eastward
off the Cape/Islands by 06Z at the latest tonight. Frontal
passage expected before sunrise Sunday morning, where a wind
shift from the NNE is expected. Winds will continue to veer
towards the ENE throughout the day.

KBOS Terminal...Moderate confidence in TAF. Uncertainty
surrounding thunderstorm coverage and duration.

KBDL Terminal...Moderate confidence in TAF. Uncertainty
surrounding thunderstorm coverage and duration.

Outlook /Monday through Thursday/...

Monday: Mainly VFR, with local IFR possible. Breezy. SHRA
likely, slight chance TSRA.

Monday Night: Mainly MVFR, with local IFR possible. Breezy.
SHRA likely, slight chance TSRA.

Tuesday: Mainly VFR, with local IFR possible. Breezy. SHRA
likely, chance TSRA.

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

Wednesday: VFR. Slight chance SHRA.

Wednesday Night: VFR.

Thursday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Sunday...High confidence.

A relatively weak pressure gradient will keep winds/seas below small
craft advisory thresholds this holiday Weekend. Some 20+ knot
WNW wind gusts over the land this afternoon may result in some
nearshore chop...but no headlines will be needed for the waters
this weekend with seas generally 3 feet or less.

Outlook /Monday through Thursday/...

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

Monday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Rain showers likely, slight chance of thunderstorms.

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Rain showers likely, chance
of thunderstorms.

Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers, slight chance of thunderstorms.

Wednesday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers.

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

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT this evening for CTZ002>004.
MA...Heat Advisory until 8 PM EDT this evening for MAZ002>023-026.
RI...Heat Advisory until 8 PM EDT this evening for RIZ001>007.
MARINE...None.

&&

DISCUSSION...Guest
AVIATION...McMinn/Guest
MARINE...Guest

In the hours before

Local storm report, Jul 4, 3:17 PM EDT, 5 hours 1 minute before

Preliminary Local Storm Report
National Weather Service Boston/Norton MA
317 PM EDT Sat Jul 4 2026

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

0309 PM     Marine Tstm Wind 1 NE Rockport           42.66N 70.60W
07/04/2026  M51 MPH          ANZ251             MA   Mesonet

            Mesonet station on Gap Head.

&&

Local storm report, Jul 4, 3:19 PM EDT, 4 hours 59 minutes before

Preliminary Local Storm Report
National Weather Service Boston/Norton MA
319 PM EDT Sat Jul 4 2026

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

0304 PM     Marine Tstm Wind 2 ENE Ipswich           42.69N 70.80W
07/04/2026  M40 MPH          ANZ251             MA   Mesonet

            Mesonet station on Little Neck.

&&

Legro

Local storm report, Jul 4, 8:05 PM EDT, 13 minutes before

Preliminary Local Storm Report
National Weather Service Boston/Norton MA
805 PM EDT Sat Jul 4 2026

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

0740 PM     Tstm Wnd Gst     2 W Burlington          41.75N 73.00W
07/04/2026  M56 MPH          Hartford           CT   Public

0749 PM     Tstm Wnd Dmg     Burlington              41.77N 72.97W
07/04/2026                   Hartford           CT   Fire Dept/Rescue

            In Burlington, CT, trees and wires down on
            Route 4. Relayed via Amateur Radio.

0755 PM     Hail             Bristol                 41.68N 72.94W
07/04/2026  M1.75 Inch       Hartford           CT   Trained Spotter

            In Bristol, golf ball sized hail fell.

0759 PM     Hail             1 W Plainville          41.67N 72.91W
07/04/2026  M1.25 Inch       Hartford           CT   Public

            In Plainville, Half Dollar sized hail fell.

&&

The office that day

Everything else NWS Boston/Norton, MA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 4, 8:02 PM EDT	Severe Thunderstorm Warning Considerable damage threat	BOX	Capitol Planning Region	27 min
Jul 5, 2:24 AM EDT	Flood Watch	BOX	Capitol Planning Region, Northeastern Connecticut Planning Region	60 hr

Nearby

Severe Thunderstorm Warnings in Connecticut, 2026 Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.