Alert archive / Connecticut / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 63, NWS Boston/Norton, MA

July 14, 2020Capitol Planning Region, Connecticut; Hampden County, Hampshire County, Massachusetts

NWS Boston/Norton, MA issued this severe thunderstorm warning at Jul 14, 2020, 12:05 PM EDT for Capitol Planning Region, Connecticut; Hampden County, Hampshire County, Massachusetts. It was in force for 55 min. 4 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 14, 2020, 12:05 PM EDT (16:05 UTC)
Expired
Jul 14, 2020, 1:00 PM EDT
In force
55 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Capitol Planning Region, CT, Hampden County, MA, Hampshire County, MA

The radar

The Albany radar (KENX), 124 km from the middle of the area, began a volume at 16:07 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

TimeReportWhereRemark
Jul 14, 12:15 PM EDTHAIL 0.75South Hadley, MA
Jul 14, 12:15 PM EDTHAIL 1South Hadley, MA
Jul 14, 12:20 PM EDTTSTM WND DMGHolyoke, MALARGE TREE DOWN ON SOUTHBOUND LANE OF RTE 91
Jul 14, 12:25 PM EDTHAIL 1.25South Hadley, MA

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 3 storm reports to this severe thunderstorm warning; the first came 10 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 nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 4.1 hours before the alert went out and 111 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-pSkew-T log-p diagram, Albany, NY at 12:00Z on 2020-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 482 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 12:00Z on 2020-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
482 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
914 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

557 
WUUS51 KBOX 141605
SVRBOX
CTC003-013-MAC013-015-141700-
/O.NEW.KBOX.SV.W.0063.200714T1605Z-200714T1700Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boston/Norton MA
1205 PM EDT Tue Jul 14 2020

The National Weather Service in Boston/Norton has issued a

* Severe Thunderstorm Warning for...
  Northwestern Tolland County in northern Connecticut...
  North central Hartford County in northern Connecticut...
  South central Hampshire County in western Massachusetts...
  Central Hampden County in western Massachusetts...

* Until 100 PM EDT.

* At 1204 PM EDT, a severe thunderstorm was located over Northampton,
  moving south at 15 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect wind damage to trees and power lines. Minor hail 
           damage to vehicles is possible.

* Locations impacted include...
  Springfield, Chicopee, Enfield, Westfield, Holyoke, Amherst,
  Northampton, Agawam, West Springfield, Ludlow, South Hadley,
  Easthampton, Longmeadow, Suffield, East Longmeadow, Wilbraham,
  Windsor Locks, Stafford, Somers and Southwick.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4233 7281 4240 7258 4203 7234 4194 7268
TIME...MOT...LOC 1604Z 340DEG 14KT 4230 7267 

HAIL...1.50IN
WIND...60MPH
 
$$

Chai
3 follow-up statements
222 
WWUS51 KBOX 141625
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1225 PM EDT Tue Jul 14 2020

CTC003-013-MAC013-015-141700-
/O.CON.KBOX.SV.W.0063.000000T0000Z-200714T1700Z/
Tolland CT-Hartford CT-Hampshire MA-Hampden MA-
1225 PM EDT Tue Jul 14 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 PM EDT
FOR NORTHWESTERN TOLLAND...NORTH CENTRAL HARTFORD...SOUTH CENTRAL
HAMPSHIRE AND CENTRAL HAMPDEN COUNTIES...

At 1224 PM EDT, a severe thunderstorm was located over Chicopee,
moving southeast at 20 mph.

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

SOURCE...Radar indicated and trained spotters. At 1220 PM, a large 
         tree was downed blocking one line of Interstate 91 in 
         Holyoke. Penny size hail was also reported in South Hadley.

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Springfield, Chicopee, Enfield, Westfield, Holyoke, Amherst,
Northampton, Agawam, West Springfield, Ludlow, South Hadley,
Easthampton, Longmeadow, Suffield, East Longmeadow, Wilbraham,
Windsor Locks, Stafford, Somers and Southwick.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 4224 7278 4233 7254 4203 7234 4194 7268
TIME...MOT...LOC 1624Z 335DEG 15KT 4220 7259 

HAIL...1.00IN
WIND...60MPH
 
$$

Loconto
972 
WWUS51 KBOX 141634
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1234 PM EDT Tue Jul 14 2020

CTC003-013-MAC013-015-141700-
/O.CON.KBOX.SV.W.0063.000000T0000Z-200714T1700Z/
Tolland CT-Hartford CT-Hampshire MA-Hampden MA-
1234 PM EDT Tue Jul 14 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 PM EDT
FOR NORTHWESTERN TOLLAND...NORTH CENTRAL HARTFORD...SOUTH CENTRAL
HAMPSHIRE AND CENTRAL HAMPDEN COUNTIES...

At 1232 PM EDT, a severe thunderstorm was located over Chicopee,
moving south at 15 mph.

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

SOURCE...Radar indicated and trained spotters. At 1220 PM, a large 
         tree was downed blocking one line of Interstate 91 in 
         Holyoke. Quarter sized hail was also reported in South 
         Hadley. 

IMPACT...Expect wind damage to trees and power lines. Minor hail 
         damage to vehicles is possible.

Locations impacted include...
Springfield, Chicopee, Enfield, Westfield, Holyoke, Amherst,
Northampton, Agawam, West Springfield, Ludlow, South Hadley,
Easthampton, Longmeadow, Suffield, East Longmeadow, Wilbraham,
Windsor Locks, Stafford, Somers and Southwick.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 4224 7278 4233 7254 4203 7234 4194 7268
TIME...MOT...LOC 1632Z 340DEG 14KT 4217 7257 

HAIL...1.00IN
WIND...60MPH
 
$$

Chai
583 
WWUS51 KBOX 141655
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
1255 PM EDT Tue Jul 14 2020

CTC003-013-MAC013-015-141704-
/O.EXP.KBOX.SV.W.0063.000000T0000Z-200714T1700Z/
Tolland CT-Hartford CT-Hampshire MA-Hampden MA-
1255 PM EDT Tue Jul 14 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN TOLLAND...NORTH
CENTRAL HARTFORD...SOUTH CENTRAL HAMPSHIRE AND CENTRAL HAMPDEN
COUNTIES WILL EXPIRE AT 100 PM EDT...
                
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 will be allowed to expire.  However small 
hail, gusty winds and heavy rain leading to localized minor flooding 
are still possible with this thunderstorm. Therefore, it will be 
followed by a Special Weather Statement. 

LAT...LON 4224 7278 4233 7254 4203 7234 4194 7268
TIME...MOT...LOC 1654Z 340DEG 14KT 4211 7254 

$$

Chai

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 14, 10:54 AM EDT, 1 hour 11 minutes earlier.

Area forecast discussion, Jul 14, 10:54 AM EDT, 1 hour 11 minutes before
Area Forecast Discussion
National Weather Service Boston/Norton MA
1054 AM EDT Tue Jul 14 2020

.SYNOPSIS...
Strong to severe thunderstorms possible across portions of
southern New England this afternoon. Main threats are damaging
wind gusts, hail and heavy rainfall which could bring localized
flash flooding. Will be cooler in comparison to the past several
days, but the humidity remains. High pressure then brings fair weather
for Wednesday and Thursday. Scattered showers and thunderstorms
return early Friday and Friday night. High pressure then bring
rain-free but very warm weather for Saturday and Sunday. Another
cold front may bring a few thunderstorms Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
1040 AM Update:

Another afternoon of scattered to numerous thunderstorms, a few
of which may become strong to severe. On that front, we are
already off and running early as storms have already developed
basically along or near I-95/Route 128 with a recent spotter
report of half-inch hail in Needham. These storms will progress
eastward towards the eastern MA waters over the next hour to 90
minutes.

Recent CAMs blossom scattered to numerous storms progressing
southeastward from NH/VT into northern MA across the remainder
of Southern New England into the afternoon, fostered by the cold
pool aloft associated with the upper low. While effective bulk
shear decreases through the day with aprch of upper low, and
temepratures/dewpoints are not as high as yesterday, the cold
pool aloft is resulting in somewhat more steep lapse rates in
mid- levels and will help sustain at least moderate convective
instability. Strong to damaging winds will be the main severe
hazard, though instances of hail certainly will be possible
given the cooler profiles/steeper lapse rates aloft. Localized
torrential downpours is a related risk, and while there aren't
the signals for storm training like we saw yesterday in NE MA
and northwest Windham County CT, if torrential rains fall over a
vulnerable spot localized street flooding could develop. Storms
are expected to decrease in number and intensity by early
evening.

Given expected numerous coverage of storms, a handful of which
may become strong to severe, have opted for an SPS to bring
awareness to the strong/severe thunder threat.

Previous Discussion...

* Isolated strong to severe thunderstorms possible across
  southern New England today. Main threats from storms are
  damaging wind gusts and heavy rainfall, which could produce
  localized flash flooding. In addition, hail cannot be ruled
  out.

* Cooler temperatures in comparison to the past couple of days.

A negatively tilted trough digs into northern New England today.
The surface low associated with the trough will remain offshore
into the Gulf of Maine.

Expect the surface low to reinforce cool, stable onshore flow
across eastern MA and RI. The interior will see north to
northeast winds throughout the day. How strong this onshore flow
is bring some questions in regards to the thunderstorm activity
today. However, further from the coast there is a better
opportunity for showers and storms.

Aloft the 500 hPa trough will dig into northern New England.
This will bring an anomalously cold air mass into the region
aloft with 500 hPa temperatures between -10 to -15 degrees
Celsius. This cold pool moving in aloft in combination with the
trough overhead and diurnal heating will result in scattered
shower and thunderstorm development. Dew points not expected to
drop much despite the northerly to northeasterly flow with
readings generally in the mid to upper 60s. So, there is plenty
of moisture available.

Stability values across New England range generally from
1000-1500 J/kg of MUCAPE. Though the ARW/NMM does feature values
increasing to 2000-2500 J/kg. Bulk shear values are around 20 to
30 kts within the 0-6 km layer. So not completely ideal wind
shear aloft, but this can be compensated for by the higher
instability. Low level lapse rates are expected to increase to 7
to 8 degrees Celsius per km. Mid level lapse rates are
supportive to maintain updrafts. Models keep values around 6 to
7 degrees Celsius per km. Do have a few hundred J/kg of DCAPE
and there is a decent amount of CAPE within the hail growth
zone. Forcing is a bit weaker today in comparison to yesterday,
so that is also a question. Think the best chance for strong to
severe storms will be across central MA into the Merrimack
Valley. This is also supported by some 2-5 km updraft helicity
swaths per the HREF and SREF Craven Brooks SIG Severe Index
values greater than or equal to 10k. This is also indicated per
the SPC Day 1 Outlook.

Along with the threat of strong to severe storms there will be
the threat of heavy rainfall. Will see PWAT values between 1.25
to 1.5 inches, which is approaching the 75th percentile per SPC
Sounding Climo for CHH. The HREF neighborhood probability
matched mean guidance does indicate that there is a 50 to 70
percent chance of 3-hr QPF values greater than 1 in, but no
probabilities of 3-hr QPF values greater than 3 in as was the
case yesterday. This again highlighting the greatest risk across
central MA into the Merrimack Valley this afternoon. Do have
some concerns for northeast MA given that storms moved through
today, so will need to closely monitor.

Will be cooler today in comparison to the past couple of days.
Flow at 850 and 925 hPa will be generally out of the northwest
to north. This will advect cooler air in. Highs range from the
mid 70s to the low 80s, though there may be come mid 80 degree
readings across the CT River Valley.

&&

.SHORT TERM /WEDNESDAY/...
Highlights

* Any showers and storms diminishing during the evening. Low
  clouds linger tonight due to onshore flow. Much cooler with
  lows falling into the 50s across the interior and the low 60s
  along the coast.

* Drier weather across southern New England on Wednesday. Cannot
  rule out an isolated shower across the CT River Valley. Cooler
  temperatures continue with readings generally in the 70s.

Tonight...

Nearly neutrally tilted trough slides offshore. Behind the
trough a ridge axis will build from the central Great Lakes into
the eastern Great Lakes.

Shower and storms diminishing as the trough lifts offshore and
due to the loss of heating. Onshore flow persists and expect low
clouds to advect further inland. Dew points falling into the
upper 50s and low 60s across the region. Will feels much more
comfortable. Low temperatures falling into the 50s across the
interior and the low 60s along the coast.

Wednesday...

Ridge axis building into western portions of New England from
the eastern Great Lakes. This will provide dry and quiet weather
across the majority of southern New England. Will have cool
northeasterly winds becoming easterly at 925 hPa. This will
continue to advect cooler air in. Dew points remain comfortable
with readings in the upper 50s and low 60s. High temperatures
generally in the 70s. Could have some low 80s across the CT
River Valley.

Not out of the question that the combination of the easterly
flow and diurnal heating results in some orographically driven
showers across the higher terrain of CT and western MA. Little
to no instability present, so do not anticipate any
thunderstorms.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Highlights...

* Mostly dry Thursday then rain and thunderstorms return late
  Thursday night and Friday

* Warmer temperatures and increasing humidity for the weekend

Details...

High pressure remains in control at the sfc with mid level ridging
aloft Wed night and Thursday. The pattern breaks down late Thursday
night and Friday as a mid level shortwave and frontal system swings
through bringing the return of rain and thunderstorms. Zonal flow
and high pressure influence keep dry and increasingly hot/humid
conditions in the forecast for the weekend into next week.

High pressure nosing down from Quebec remains in place Wednesday
night into Thursday. This keeps southern New England largely dry
with partly cloudy skies as moisture lingers around 850 mb.
Temperature-wise things remain relatively comfortable and below
normal; in the low 80s inland, mid-upper 70s east. This will be the
last day of the cooling NE flow influence, however, as winds shift
out of the SE late in the day and SW by Thursday night as the high
moves out.

On its heels is a sfc low over southern Canada moving into northern
New England Thursday night and Friday. Timing has been slowed down a
bit, but by early Friday morning WAA showers should have moved into
western MA ahead of the cold front which moves through around late
Friday night or early Saturday morning. Ahead of the cold front
convective parameters are marginally favorable for a few strong
storms (CAPE near 1000 J/kg and bulk shear of 25-30 kts) but lapse
rates are rather poor which could be a limiting factor. Thunderstorm
potential will likely be dependent on the timing of the cold front
which, if it comes through as slowly as it's looking currently, may
be too late to take advantage of the more favorable afternoon
temperature profile. Stay tuned.

For the weekend the post frontal airmass looks drier with high
pressure building over southern New England. This brings with it the
return of normal to above normal temperatures nearing 90 F. The
airmass becomes less comfortable too, as higher humidity returns on
southerly flow; dewpoints once again approaching 70 F.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

15z TAF Update:

Today...Moderate confidence.

While VFR most of the time (except MVFR-IFR Cape/Islands),
expecting scattered to numerous showers and thunderstorms to
develop 17-00z. Already are some storms as of 15z near BOS and
have a short period of VCTS. Though there may be a break in the
next hour or two, expecting that after 17z that storms will
again fire up in greater number. A few may become strong to
locally severe with gusty winds and hail and short-lived/brief
sub-VFR ceiling/visbys. Ceilings should remain VFR, but
deteriorate to MVFR to IFR late across coastal locations as flow
becomes onshore.

Tuesday night...Moderate confidence

Northeasterly flow at 5 to 10 kts. Should see MVFR to borderline
IFR ceilings. Think that the patchy fog will be limited, but
best shot will be across locations that receive precipitation
today.

Wednesday...High confidence

Any MVFR to borderline IFR ceilings improving to VFR during the
morning as high pressure builds in. Only exception is across
Cape Cod and the Islands where MVFR ceilings may linger. Winds
shifting to an easterly direction.

KBOS Terminal...Moderate confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly VFR, with local IFR possible.

Thursday: VFR.

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

Friday: Mainly MVFR, with areas VFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Friday Night: Mainly VFR, with areas IFR possible. Slight
chance SHRA, isolated TSRA.

Saturday: VFR.

&&

.MARINE...
Small Craft Advisories remain in effect across the southern
waters due to wave heights around 5 ft. Low clouds and fog
across the eastern waters into late this morning. May need a
Small Craft Advisory late tonight across the eastern waters due
to building waves. This is a result of strengthening northeast
winds. Have held off in the current update as have some doubts
in wind speeds and resultant waves.

High Surf Advisory remains in effect for the Islands, including
Block Island, until Tuesday evening for south facing beaches
due to the rip current risk and breaking 4-6 ft waves in the
surf zone.

Outlook /Wednesday Night through Saturday/...

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

Thursday: Winds less than 25 kt.

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

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

Saturday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 8 PM EDT this evening for MAZ023-024.
RI...High Surf Advisory until 8 PM EDT this evening for RIZ008.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ235-
     237-255-256.

&&

SYNOPSIS...BL/BW
NEAR TERM...BL/Loconto/BW
SHORT TERM...BL
LONG TERM...BW
AVIATION...BL/Loconto/BW
MARINE...BL/Loconto/BW
Hazardous weather outlook, Jul 14, 4:35 AM EDT, 7 hours 30 minutes before
Hazardous Weather Outlook
National Weather Service Boston/Norton MA
435 AM EDT Tue Jul 14 2020

MAZ023-024-RIZ008-150845-
Dukes MA-Nantucket MA-Block Island RI-
435 AM EDT Tue Jul 14 2020

...HIGH SURF ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...

This Hazardous Weather Outlook is for southeastern Massachusetts
and southern Rhode Island.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   High Surf Advisory.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ANZ230>237-250-251-254>256-150845-
Boston Harbor-Cape Cod Bay-Nantucket Sound-Vineyard Sound-
Buzzards Bay-Rhode Island Sound-Narragansett Bay-Block Island Sound-
Coastal waters east of Ipswich Bay and the Stellwagen Bank National
Marine Sanctuary-Massachusetts Bay and Ipswich Bay-
Coastal waters from Provincetown MA to Chatham MA to Nantucket MA
out 20 nm-
Coastal Waters extending out to 25 nm South of Marthas Vineyard and
Nantucket-
Coastal Waters from Montauk NY to Marthas Vineyard extending out to
20 nm South of Block Island-
435 AM EDT Tue Jul 14 2020

This Hazardous Weather Outlook is for Massachusetts and Rhode
Island coastal waters.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

CTZ002>004-MAZ002>022-026-RIZ001>007-150845-
Hartford CT-Tolland CT-Windham CT-Western Franklin MA-
Eastern Franklin MA-Northern Worcester MA-Central Middlesex MA-
Western Essex MA-Eastern Essex MA-Western Hampshire MA-
Western Hampden MA-Eastern Hampshire MA-Eastern Hampden MA-
Southern Worcester MA-Western Norfolk MA-Southeast Middlesex MA-
Suffolk MA-Eastern Norfolk MA-Northern Bristol MA-
Western Plymouth MA-Eastern Plymouth MA-Southern Bristol MA-
Southern Plymouth MA-Barnstable MA-Northern Middlesex MA-
Northwest Providence RI-Southeast Providence RI-Western Kent RI-
Eastern Kent RI-Bristol RI-Washington RI-Newport RI-
435 AM EDT Tue Jul 14 2020

This Hazardous Weather Outlook is for northern Connecticut, central
Massachusetts, eastern Massachusetts, northeastern Massachusetts,
southeastern Massachusetts, western Massachusetts, northern Rhode
Island and southern Rhode Island.

.DAY ONE...Today and tonight.

Isolated strong to severe thunderstorms are possible across southern
New England today. The main threats with storms are damaging wind
gusts, hail, frequent lightning and heavy rainfall. The heavy
rainfall may lead to localized flash flooding.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

For more information on upcoming hazardous weather, please see the
Area Forecast Discussion on our webpage for the latest forecast
thinking. There is also our Enhanced Hazardous Weather Outlook at
www.weather.gov/box/ehwo

For the latest updates...please visit our webpage at
www.weather.gov/boston

You can follow us on Facebook at
www.facebook.com/us.nationalweatherservice.boston.gov

You can follow us on Twitter at
@NWSBoston

In the hours before

Special weather statement, Jul 14, 9:50 AM EDT, 2 hours 15 minutes before
Special Weather Statement
National Weather Service Boston/Norton MA
950 AM EDT Tue Jul 14 2020

CTZ002>004-MAZ002>024-026-RIZ001>008-141600-
Hartford CT-Tolland CT-Windham CT-Western Franklin MA-
Eastern Franklin MA-Northern Worcester MA-Central Middlesex MA-
Western Essex MA-Eastern Essex MA-Western Hampshire MA-
Western Hampden MA-Eastern Hampshire MA-Eastern Hampden MA-
Southern Worcester MA-Western Norfolk MA-Southeast Middlesex MA-
Suffolk MA-Eastern Norfolk MA-Northern Bristol MA-
Western Plymouth MA-Eastern Plymouth MA-Southern Bristol MA-
Southern Plymouth MA-Barnstable MA-Dukes MA-Nantucket MA-
Northern Middlesex MA-Northwest Providence RI-
Southeast Providence RI-Western Kent RI-Eastern Kent RI-
Bristol RI-Washington RI-Newport RI-Block Island RI-
Including the cities of Hartford, Windsor Locks, Union, Vernon,
Putnam, Willimantic, Charlemont, Greenfield, Orange, Barre,
Fitchburg, Framingham, Lowell, Lawrence, Gloucester,
Chesterfield, Blandford, Amherst, Northampton, Springfield,
Milford, Worcester, Foxborough, Norwood, Cambridge, Boston,
Quincy, Taunton, Brockton, Plymouth, Fall River, New Bedford,
Mattapoisett, Chatham, Falmouth, Provincetown, Vineyard Haven,
Nantucket, Ayer, Foster, Smithfield, Providence, Coventry,
West Greenwich, East Greenwich, Warwick, West Warwick, Bristol,
Narragansett, Westerly, Newport, and New Shoreham
950 AM EDT Tue Jul 14 2020

...SCATTERED STRONG TO LOCALLY SEVERE THUNDERSTORMS POSSIBLE
TODAY...

Scattered to numerous showers and thunderstorms are expected to
develop today across a large part of Southern New England. A few
storms may become strong to locally severe, with the main severe
weather threat being damaging straight-line winds with hail a
secondary threat. In addition, heavy rainfall associated with the
thunderstorms may result in localized street flooding.

Storms are anticipated to develop near northern Massachusetts by
late this morning, with storms moving southeastward through the
afternoon across the remainder of Massachusetts, Rhode Island into
northern Connecticut. Storms are expected to decrease in number
and intensity by early this evening.

Stay tuned to local media and television outlets for later
statements and possible warnings. Be prepared to take the
necessary preparedness actions if warnings are issued for your
area.

Loconto
Special weather statement, Jul 14, 10:36 AM EDT, 1 hour 29 minutes before
Special Weather Statement
National Weather Service Boston/Norton MA
1036 AM EDT Tue Jul 14 2020

MAZ005-007-013>016-019-141515-
Eastern Essex MA-Eastern Plymouth MA-Suffolk MA-Western Norfolk MA-
Central Middlesex County MA-Eastern Norfolk MA-
Southeast Middlesex MA-
1036 AM EDT Tue Jul 14 2020

...A CLUSTER OF STRONG THUNDERSTORMS MOVING INTO THE BOSTON AREA...

At 1034 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Winchester to near Brookline. Movement was
northeast at 10 mph.

Hail up to penny size and winds in excess of 40 mph will accompany
these storms. Trained spotters in Needham recently reported half-
inch hail from these storms. In addition, expect brief heavy
donwpours and cloud to ground lightning.

Locations impacted include...
Boston, Cambridge, Quincy, Lynn, Newton, Somerville, Waltham, Malden,
Brookline, Medford, Weymouth, Revere, Peabody, Arlington, Everett,
Salem, Beverly, Woburn, Braintree and Chelsea.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get indoors when these storms approach. Winds may be strong enough to
produce minor damage, such as a few downed branches.

These storms may intensify and become capable of producing damage.
Stay tuned for updated statements and possible warnings.

&&

LAT...LON 4253 7084 4255 7085 4254 7090 4254 7087
      4250 7089 4252 7085 4250 7084 4246 7089
      4246 7094 4243 7091 4242 7091 4242 7094
      4241 7099 4237 7096 4234 7088 4221 7091
      4222 7124 4252 7120 4256 7083
TIME...MOT...LOC 1434Z 238DEG 7KT 4245 7113 4229 7115

Loconto
Special weather statement, Jul 14, 11:00 AM EDT, 1 hour 5 minutes before
Special Weather Statement
National Weather Service Boston/Norton MA
1100 AM EDT Tue Jul 14 2020

MAZ020-023-141600-
Southern Bristol MA-Dukes MA-
1100 AM EDT Tue Jul 14 2020

...STRONG THUNDERSTORM OVER BUZZARDS BAY MOVING TOWARDS THE
ELIZABETH ISLANDS AND MARTHA'S VINEYARD...

At 1058 AM EDT, Doppler radar was tracking a strong thunderstorm near
Gosnold, or near Dartmouth, moving southeast at 10 mph.

Hail up to one-half inch and winds in excess of 40 mph will
accompany this storm. Torrential rains and frequent lightning can
also be expected from this storm.

Locations impacted include...
Oak Bluffs, Edgartown, Tisbury, Aquinnah, West Tisbury, Chilmark and
Gosnold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get indoors when this storm approaches. Winds may be strong enough to
produce minor damage, such as a few downed branches.

Frequent lightning was occurring. Lightning can strike far away from
the storm. Go inside a building or vehicle. Wait at least 30 minutes
until after the storm has passed to resume outdoor activities.

These storms may intensify and become capable of producing damage.
Stay tuned for updated statements and possible warnings.

&&

LAT...LON 4141 7095 4139 7088 4152 7099 4152 7098
      4145 7092 4156 7094 4135 7083 4135 7078
      4143 7070 4145 7084 4151 7072 4150 7071
      4147 7076 4144 7072 4147 7062 4140 7050
      4135 7056 4134 7071 4130 7078
TIME...MOT...LOC 1458Z 309DEG 11KT 4148 7091

Loconto
Special weather statement, Jul 14, 11:01 AM EDT, 1 hour 4 minutes before
Special Weather Statement
National Weather Service Boston/Norton MA
1101 AM EDT Tue Jul 14 2020

MAZ002-003-008-010-141545-
Western Franklin MA-Western Hampshire MA-Eastern Franklin MA-
Eastern Hampshire MA-
1101 AM EDT Tue Jul 14 2020

...STRONG THUNDERSTORM APPROACHING FRANKLIN AND HAMPSHIRE COUNTY
IN MASSACHUSETTS...

At 1059 AM EDT, Doppler radar was tracking a strong thunderstorm near
Conway, or 8 miles southwest of Greenfield, moving southeast at 20
mph.

Penny size hail, winds in excess of 40 mph and heavy rainfall will
accompany this storm.

Locations impacted include...
Amherst, Northampton, Greenfield, Deerfield, South Hadley, Montague,
Granby, Hadley, Sunderland, Hatfield, Williamsburg, Buckland, Conway,
Shelburne, Leverett, Shutesbury, Ashfield, Colrain, Gill and Whately.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get indoors when this storm approaches. Winds may be strong enough
to produce minor damage, such as a few downed branches. There may be
localized urban poor drainage flooding from the heavy rainfall. Do
not drive through flooded roadways.

Frequent lightning was occurring. Lightning can strike far away from
the storm. Go inside a building or vehicle. Wait at least 30 minutes
until after the storm has passed to resume outdoor activities.

&&

LAT...LON 4269 7272 4249 7231 4228 7254 4243 7274
      4242 7275 4243 7275 4253 7288
TIME...MOT...LOC 1459Z 311DEG 16KT 4255 7274

Chai
Special weather statement, Jul 14, 11:26 AM EDT, 39 minutes before
Special Weather Statement
National Weather Service Boston/Norton MA
1126 AM EDT Tue Jul 14 2020

MAZ002-003-141615-
Western Franklin MA-Eastern Franklin MA-
1126 AM EDT Tue Jul 14 2020

...STRONG THUNDERSTORM MOVING INTO FRANKLIN COUNTY FROM SOUTHERN
WINDHAM COUNTY VERMONT...

At 1126 AM EDT, Doppler radar was tracking a strong thunderstorm over
Leyden, or 8 miles north of Greenfield, moving southeast at 15 mph.

Penny size hail and winds in excess of 40 mph will accompany this
storm, along with brief downpours and cloud to ground lightning.

Locations impacted include...
Greenfield, Orange, Deerfield, Montague, Northfield, Bernardston,
Buckland, Conway, Shelburne, Erving, Colrain, Gill, Charlemont,
Wendell, Warwick, Leyden and Heath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get indoors when this storm approaches. Winds may be strong enough to
produce minor damage, such as a few downed branches.

These storms may intensify and become capable of producing damage.
Stay tuned for updated statements and possible warnings.

&&

LAT...LON 4273 7251 4259 7231 4250 7268 4273 7282
TIME...MOT...LOC 1526Z 324DEG 14KT 4273 7263

Loconto
Local storm report, Jul 14, 12:03 PM EDT, 2 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1203 PM EDT TUE JUL 14 2020

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

1004 AM     HAIL             HAVERHILL               42.78N  71.09W
07/14/2020  M0.75 INCH       ESSEX              MA   AMATEUR RADIO

&&

EVENT NUMBER BOX2001706

WS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 13, 8:16 PM EDTSpecial Weather StatementBOX44 min
Jul 14, 1:00 PM EDTSpecial Weather StatementBOX45 min
Jul 14, 1:08 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region, Northeastern Connecticut Planning Region67 min
Jul 13, 8:08 PM EDTSpecial Weather StatementBOXMiddlesex52 min
Jul 13, 8:12 PM EDTSpecial Weather StatementBOXHampden63 min
Jul 13, 8:31 PM EDTSevere Thunderstorm WarningBOXHampden, Hampshire41 min
Jul 13, 8:57 PM EDTSpecial Weather StatementBOXMiddlesex, Suffolk48 min
Jul 13, 9:30 PM EDTSpecial Weather StatementBOXSuffolk45 min
Jul 14, 9:42 AM EDTSpecial Weather StatementBOXEssex63 min
Jul 14, 10:36 AM EDTSpecial Weather StatementBOXSuffolk39 min
Jul 14, 11:00 AM EDTSpecial Weather StatementBOXDukes60 min
Jul 14, 11:01 AM EDTSpecial Weather StatementBOXFranklin44 min
Jul 14, 11:17 AM EDTSpecial Marine WarningBOX58 min
Jul 14, 11:26 AM EDTSpecial Weather StatementBOXFranklin49 min
Jul 14, 11:35 AM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester55 min
Jul 14, 12:19 PM EDTSpecial Weather StatementBOXFranklin41 min
Jul 14, 12:29 PM EDTSpecial Weather StatementBOXFranklin46 min
Jul 14, 12:31 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester42 min
Jul 14, 1:03 PM EDTSpecial Weather StatementBOXWorcester42 min
Jul 14, 1:12 PM EDTSpecial Weather StatementBOXWorcester48 min
Jul 14, 1:46 PM EDTSevere Thunderstorm WarningBOXBristol59 min
Jul 14, 1:48 PM EDTSpecial Marine WarningBOX57 min
Jul 14, 1:53 PM EDTSpecial Weather StatementBOXHampden37 min
Jul 14, 2:10 PM EDTSpecial Weather StatementBOXMiddlesex50 min
Jul 14, 2:11 PM EDTSpecial Marine WarningBOX49 min
Jul 14, 2:24 PM EDTFlash Flood WarningBOXBristol100 min
Jul 14, 2:37 PM EDTSevere Thunderstorm WarningBOXBristol68 min
Jul 14, 3:03 PM EDTSpecial Marine WarningBOX42 min
Jul 14, 3:10 PM EDTSmall Craft AdvisoryBOX33 hr
Jul 14, 3:33 PM EDTSpecial Weather StatementBOXEssex57 min
Jul 14, 3:40 PM EDTSpecial Marine WarningBOX65 min
Jul 14, 3:45 PM EDTSpecial Weather StatementBOXFranklin45 min
Jul 14, 4:21 PM EDTSpecial Weather StatementBOXEssex39 min
Jul 14, 4:26 PM EDTSpecial Marine WarningBOX64 min
Jul 14, 4:40 PM EDTSpecial Weather StatementBOXHampshire50 min
Jul 14, 4:57 PM EDTSpecial Marine WarningBOX48 min
Jul 14, 5:04 PM EDTSpecial Weather StatementBOXSuffolk41 min
Jul 14, 5:57 PM EDTSpecial Weather StatementBOXNorfolk48 min
Jul 14, 6:41 PM EDTSpecial Weather StatementBOXBristol49 min
Jul 14, 7:50 PM EDTSpecial Weather StatementBOXWorcester40 min

Nearby

Severe Thunderstorm Warnings in Connecticut, 2020Severe Thunderstorm Warnings in Massachusetts, 2020Every severe thunderstorm warning in 2020

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.