Severe Thunderstorm Warning 24, NWS Boston/Norton, MA

060 
WWUS51 KBOX 191935
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
335 PM EDT Thu Jun 19 2025

CTC003-013-MAC013-192015-
/O.CON.KBOX.SV.W.0024.000000T0000Z-250619T2015Z/
Tolland CT-Hartford CT-Hampden MA-
335 PM EDT Thu Jun 19 2025

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR NORTHWESTERN TOLLAND...NORTHERN HARTFORD AND SOUTH CENTRAL
HAMPDEN COUNTIES...

At 335 PM EDT, a severe thunderstorm was located over Avon, or near
West Hartford, moving northeast at 35 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         trees and power lines.

Locations impacted include...
Springfield, Hartford, New Britain, West Hartford, East Hartford,
Enfield, Westfield, Newington, Windsor, Agawam, West Springfield,
South Windsor, Farmington, Simsbury, Bloomfield, Avon, Plainville,
Longmeadow, Suffield, and East Longmeadow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4167 7281 4179 7299 4181 7298 4181 7295
      4184 7294 4185 7295 4215 7273 4199 7236
TIME...MOT...LOC 1935Z 219DEG 31KT 4180 7283 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

CAM

776 
WWUS51 KBOX 191959
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
359 PM EDT Thu Jun 19 2025

CTC003-013-MAC013-192009-
/O.CAN.KBOX.SV.W.0024.000000T0000Z-250619T2015Z/
Tolland CT-Hartford CT-Hampden MA-
359 PM EDT Thu Jun 19 2025

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

The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
northern Connecticut...and western Massachusetts.

LAT...LON 4167 7281 4179 7299 4181 7298 4181 7295
      4184 7294 4185 7295 4215 7273 4199 7236
TIME...MOT...LOC 1957Z 221DEG 35KT 4198 7262 

$$

CAM

Area Forecast Discussion
National Weather Service Boston/Norton MA
310 PM EDT Thu Jun 19 2025

.SYNOPSIS...
High heat and humidity today with strong to severe thunderstorms
possible this afternoon and evening. The best chance of severe
weather today is in interior Southern New England. Turning drier and
much less humid on Friday, but also quite windy by late June
standards. Seasonably warm temperatures are expected this weekend.
Monitoring for thunderstorm potential this weekend but the overall
risk is low. A multi-day stretch of significant heat is looking more
likely for Monday through Wednesday, with the potential for heat to
reach dangerous levels.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Key Messages:

* Heat Advisory in effect through 8PM with apparent temps near triple
  digits

* Strong to severe thunderstorms possible this afternoon, especially
  after 4 PM. A thunderstorm watch in effect for western MA and
  northern CT this afternoon

Details:

Heat and Humidity...

A Heat Advisory remains in effect through 8 PM this evening. We've
already seen several hours of full sun today, and the temperatures
skyrocketed this morning in response. Expecting temperatures to
continue to warm into the lower to mid 90s, and with dewpoint
temperatures in the low to mid 70s, it may feel closer to the low
100s.

Remember to stay hydrated and limit strenuous outdoor activities
today. Take frequent breaks in locations with air conditioning and
wear light weight and light colored clothing.

Strong to Severe Thunderstorms This Afternoon...

Starting to see some discrete cells firing ahead of the main cold
front in eastern NY and western CT. These storms are riding the pre-
frontal trough through southern New England and outrunning most of
the forcing, but we expect the main line to form around 4 PM and
move east throughout the afternoon and into the evening. Some of
these storms are expected to become severe given the hot and humid
airmass in place.

A thunderstorm watch has been issued for Worcester County and
extending west to the NY/MA state line as well as extending south
into CT. While the greatest risk for severe weather today is within
the watch area, the somewhat earlier start to storms supports a
growing potential for thunderstorms making the trip into eastern MA
and northern RI.

Damaging straight line winds continue to be the main hazard, with
torrential rainfall, large hail, and a possible tornado remaining as
secondary hazards.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Key Messages:

* Sunny and slightly cooler Friday

* High winds likely during the day on Friday

Friday and Friday Night:

Clearing skies and lots of sun combine with a low-level jet around
40 kts and lead to the likelihood of quite high winds at the surface.
Thinking we could see areas of 30-45 mph with a few gusts near
50 mph in parts of western, central, and northeastern
Massachusetts and possibly go with a Wind Advisory for Friday.
Already went with a Gale Warning for Boston Harbor,
Massachusetts Bay, and Ipswich bay for the day. Wind speeds
should decrease more steadily into Friday evening.

We'll start to dry out a little bit for the start of the weekend
once the post-FROPA airmass moves in. Temperatures look to be in the
mid 80s across the interior and mid to upper 70s across the Cape and
Islands.&&

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Key Messages:

* More seasonable temperatures for the weekend behind cold front.

* Slight chance for showers and thunderstorms early Saturday but
  coverage is in question.

* Multiple days of dangerous heat still expected through mid-week
  next week. Air temperatures could rise as high as 100 degrees with
  humidity making things feel even hotter. Greatest chance across
  the interior, especially in river valleys and urban areas.

Little in the way of changes with regards to the evolution of the
upper-level pattern in the 3-7 day range. Heights are still expected
to  build across the eastern CONUS as a trough deepens over the
western CONUS. This results in a strong ridge centered over the Ohio
Valley and Mid Atlantic. Ensemble guidance suggests that 500
millibar heights rise to as high as 597 dm by Tuesday. This setup
likely brings the hottest conditions of the season so far starting
Monday and lasting through Wednesday. Widespread 90's, and even a
few 100-degree readings will be likely across the region. Locally
hotter conditions are possible in river valleys where downslope flow
may warm things by a few degrees.

Saturday and Sunday:

The warm-up begins Saturday as heights start to build over the
region. Temperatures will be near to slightly above normal with
highs rising into the mid and upper 80s except across the Cape and
Islands where southwesterly flow will likely keep things a bit
cooler. High temperatures climb a bit more on Sunday, likely
reaching the upper 80s and lower 90s across the interior.

Outside of the increasing temperatures, there is a slight chance for
a few showers or thunderstorms earlier Saturday. A weak shortwave
moving around the periphery of the building ridge may bring a round
of showers and storms mainly across northwestern areas. At the
moment the risk is quite low as the storms will be battling rising
heights and limited surface instability.

Through Mid-Week:

Confidence in a significant heat event continues as guidance shows
near unanimous agreement in dangerously hot conditions. Heat starts
to build on Monday with ensemble guidance showing probs near 100
percent for high temperatures >90F across much of the interior. The
NBM suggests even hotter conditions on Tuesday with widespread 90-
95% probs of high temperatures exceeding 95F! A few spots in area
river valleys may approach 100 degrees with light westerly downslope
flow. The idea for widespread heat is further supported by 850mb
temperatures soaring to +22-24C Monday and Tuesday! This is an
impressive signal considering we are still more than 120 hours away
from the event. Some relief is possible Wednesday as low pressure
passing through the Canadian Maritimes swings a weak backdoor cold
front through the area. Guidance suggests than an onshore flow
develops by Wednesday afternoon. The onshore flow could bring a
relief from the hot weather, mainly for coastal areas and much of
eastern MA.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

18Z TAF Update:

Today: High confidence in trends, though moderate on timing.

At least IFR is likely to continue over the Cape and Islands
much of the day. VFR with hazy conditions once stratus
dissipates.

Growing consensus in scattered to numerous t-storms between
18-23z for BAF-BDL-HFD-ORH corridor, some which may turn severe.
Elected for prevailing VCTS with TEMPO 2 SM +TSRA in the
aforementioned timeframe. It's still a question if BOS, PVD and
BED sees t-storms but the potential seems to be on the increase,
best chance between 22-00z. Maintained PROB30s for these TAFs,
and later TAF issuances could increase the t-storm potential
here. Damaging wind gusts and torrential downpours are the
primary severe-storm hazards. SW winds increase to around 10 kt
by late this morning, with developing gusts to 20-25 kt during
the afternoon.

Tonight: High confidence.

A low chance for lingering TSRA thru 02z but improvement is
expected at all airports. IFR stratus and fog out over the Cape
and Islands may still linger until we see a gusty westerly
windshift overnight. SW to W winds increase to around 10-15 kt
with gusts low-20s kt range and LLWS for the Cape and Islands
from a 40kt westerly low level jet.

Friday: High confidence.

VFR. W/WNW winds become gusty by late morning, with speeds
13-18 kt and gusts 25-35 kt.

KBOS Terminal...Moderate confidence in TAF.

IFR ceilings scatter to VFR after 14z, with possible HZ due to
very humid air. Monitoring for possible TSRA 22-00z; while
confidence is still lower on occurrence, the potential continues
to increase. Maintained PROB30 -TSRA for now. SW winds becoming
10-13 kt today with gusts 20-23 kt, with a windshift to W
overnight at similar speeds.

KBDL Terminal...Moderate confidence in TAF.

IFR ceilings scatter to VFR 14-15z, with possible HZ due to
very humid air. Greater potential for TSRA/+TSRA between 18-23z
and indicated VCTS starting 18z with TEMPO 2SM +TSRA 19-23z due
to growing confidence. Damaging winds, frequent lightning and
heavy downpours all threats in +TSRA. S winds around 10-12 kt
with gusts to 20 kt today, then with a windshift to W around
midnight at similar speeds.

Outlook /Saturday through Tuesday/...

Saturday: VFR.

Saturday Night through Sunday: Mainly VFR, with areas MVFR
possible. Breezy. Slight chance SHRA, slight chance TSRA.

Sunday Night: VFR. Breezy.

Monday through Monday Night: VFR.

Tuesday:

&&

.MARINE...
Forecaster Confidence Levels...

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

Small craft advisories have been expanded to all waters starting
this afternoon and were also extended into Friday. SW gusts
today should reach into the 25 kt range, although we expect
stronger gusts on Friday on all waters to around 30 kt. Gusts
could approach near gale force at times on Friday. Seas will
also be building today to around 3-5 ft, and then increase to
around 4-7 ft on Friday.

Because of the building seas and SW to W winds expected for
today and tonight, we've also hoisted a rip current statement
for today and Friday on south-facing beaches. It is somewhat
borderline today, but the threat for dangerous rip currents
should increase tonight and into Friday.

Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt.

Saturday Night: Winds less than 25 kt. Slight chance of rain
showers.

Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Seas locally approaching 5 ft. Slight chance of
rain showers.

Sunday Night through Tuesday: Winds less than 25 kt.

&&

.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 MAZ003>007-
     010>019-026.
     High Risk for Rip Currents through Friday evening for MAZ023-024.
RI...Heat Advisory until 8 PM EDT this evening for RIZ001-002.
     High Risk for Rip Currents through Friday evening for RIZ008.
MARINE...Gale Warning from 9 AM to 7 PM EDT Friday for ANZ230-251.
     Small Craft Advisory until 8 PM EDT Friday for ANZ231>237-250-
     254>256.

&&

SYNOPSIS...Frank/McMinn/FT
NEAR TERM...Frank/McMinn
SHORT TERM...Frank/McMinn
LONG TERM...FT
AVIATION...Frank/McMinn
MARINE...