An approaching cold front brought scattered thunderstorms to southeastern Massachusetts. Robust instability developed by mid morning leading to t-storms with heavy rain and gusty winds.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOX wrote it up.
An approaching cold front brought scattered thunderstorms to southeastern Massachusetts. Robust instability developed by mid morning leading to t-storms with heavy rain and gusty winds. Nantucket saw a good amount of damage as did Easton and Raynham.
The local office's own words before the first event, 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 the first event at Aug 13, 1:49 PM EST, 1 minute earlier.
Area Forecast Discussion National Weather Service Boston/Norton MA 249 PM EDT Sun Aug 13 2023 .SYNOPSIS... An approaching cold front will bring scattered showers and thunderstorms this afternoon, then trending drier by this evening. Dry weather lasts through Monday, then another round of showers and a few thunderstorms is expected Monday night into Tuesday. The biggest threat at this time appears to be heavy rain. Drying out Wednesday and Thursday then the risk for showers return Thursday night into Friday with a frontal passage. Mainly dry next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 245 PM Update: Most intense t-storm so far this afternoon continues to be near the waters in between Nantucket and Martha's Vineyard, which has shown transient supercell characteristics, as it moves over the northern end of Nantucket and into Nantucket Sound until 315 PM. Meanwhile, a sfc cold front associated with a subtle shortwave disturbance aloft per WV imagery moving through interior southern VT is producing mainly isolated showers, although one storm is deepening over southeast Hampden County. Considerable dry air aloft is seen on lower level water vapor imagery, although radar and satellite trends indicate a potential increase in storm intensity. Additional storms may develop and may pulse to strong/severe levels through 7 PM from east of Hartford CT to Nashua NH eastward, as they move into an air mass characterized by moderately strong instability (e.g. MLCAPEs in the 1500-2000 J/kg neighborhood in eastern MA), although coverage of storms may be limited by the deeper dry air aloft. Storms should diminish in coverage and intensity as sfc cold front shifts offshore shortly before or around sundown. Otherwise, anticipate generally tranquil weather for the evening and overnight hrs with winds shifting from SW to W/WNW and with lowering dewpoints from NW to SE with time. Will see increasing high cloud cover late in the overnight into early Monday morning but dry weather to prevail. Lows in the upper 50s to mid 60s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... 245 PM Update: Sfc high pressure passing to our southern waters should allow for winds becoming WSW to SW. Thus the decrease in humidity level toward more tolerable levels is likely to be brief, with rising dewpoints anticipated by the afternoon ahead of a more potent shortwave disturbance aloft coming into the Gt Lakes and western New York. First part of Monday looks dry however, with steadily increasing mid to high clouds streaming in from SW to NE. Cloud cover may temper how warm temperatures may get, but still anticipate temps in the lower 80s. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Highlights... * Increasing risk for showers and a few t-storms Mon night into Tue. Heavy rainfall is the main threat * Mainly dry and seasonable Wed/Thu * Chance of showers Fri, then mainly dry next weekend Monday night into Tuesday night... Fairly potent mid level wave and surface low moves across the Gt Lakes Mon night with warm front south of New Eng. A surge of anomalous PWATs over 2 inches will lift northward into SNE as a shortwave tracks across SNE leading to increasing risk of showers Mon night and perhaps an isolated t-storm, although surface and elevated instability is confined south of New Eng Mon night. Forecast confidence diminishes Tue regarding heavy rainfall and severe threat. Gt Lakes mid level wave weakens and lifts NE Tue into Tue night tracking to the north and west where best forcing expected. Forecast guidance suggesting warm front may get stuck near or south of the coast which will limit instability and severe weather risk. The potential for localized heavy rainfall appears to be the primary risk Mon night into Tue evening as PWATs exceed 2 inches with modest forcing from shortwave Mon night and right entrance region of approaching upper jet Tue into Tue night. The column will be drying from west to east after 00z Wed so rainfall risk diminishes overnight Tue night. Highs will likely remain in the 70s Tue if warm front remains to the south with easterly flow across SNE. Wednesday into Friday... Looks mainly dry Wed-Thu although can't rule out a spot shower Wed as the mid level trough moves through. Then next upstream trough approaches from the west and moves though Friday which will bring chance of showers Thu night into Fri. Timing and amplitude differences exist with the guidance which will impact timing of when showers exit Fri. Near seasonable temps. Next weekend... Mainly dry conditions but considerable uncertainty with how far north and east the central US subtropical ridge builds which will impact temps next weekend. GFS is most aggressive with ridge building into the NE with increasing heat by Sunday, while ECMWF keeps the ridge suppressed with polar jet across New Eng keeping heat to the south. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18Z TAF Update: Through 00z Monday: High confidence. Severe t-storms still in the waters south of MVY/ACK will pose a TSRA risk for ACK thru 20z, with VCTS for FMH and ACK for same timeframe. Elsewhere, generally VFR. However watching some shallow- depth SHRA across western MA and near BDL; will include VCSH for now for most of the central and eastern airports, but may have to opt for VCTS/TEMPO TSRA if storms can strengthen further as they move east into a more unstable setting. TSRA development still isn't set in stone but risk increases in the 20-23z window. S/SW winds around 10 kt become WSW to W around 10 kt or less late. Tonight and Monday: High confidence. VFR, with increasing covg of mid to high clouds. W/WSW winds 10 kt or less. Monday Night: Moderate confidence. VFR early, though deterioration to sub-VFR with another round of SHRA/TSRA after 03z. Some storms may become strong. Confidence in timing and strength of storms is pretty low and that may need later refining. WSW winds become S/SE and increase to around 10-12 kt. KBOS TAF...High confidence in TAF. VFR with S/SW winds. Possible TS around 20-22z but not a sure bet. Will reassess and include mention if looks more apparent. Wind shift to W 23-01z. KBDL TAF...High Confidence. VFR should prevail. Low risk for VCSH/VCTS 18-21z. Windshift to W around 21-22z. TAF Outlook /Monday Night through Thursday/... Monday: VFR. Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA, isolated TSRA. Tuesday: MVFR/IFR conditions possible. SHRA likely, isolated TSRA. Tuesday Night: Mainly VFR, with local IFR possible. Chance SHRA. Wednesday: Mainly VFR, with local MVFR possible. Wednesday Night through Thursday: VFR. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 245 PM Update: Forecast confidence overall is high. Winds and seas generally are sub-SCA through Monday with SW winds 10-15 kt and seas 3 ft or less through tonight. Greater hazard to boaters this afternoon is isolated severe storms especially in Nantucket Sound and in the waters south of Nantucket. Tranquil weather continues into Monday as well with winds W to WSW 10-15 kt and seas 3 ft or less. More active marine weather arrives later Monday night into early Tuesday, with winds become SE to E around 10-15 kt with gusts to 20 kt and seas 3 ft or less; however another round of showers and thunderstorms are anticipated from SW to NE for Monday night into early Tuesday. Locally rough seas, strong winds and heavy rain reducing visby are possible in and near thunderstorms. Outlook /Monday Night through Thursday/... Monday Night: Winds less than 25 kt. Chance of rain showers, isolated thunderstorms. Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, isolated thunderstorms. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Wednesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Thursday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && SYNOPSIS...Loconto/KP NEAR TERM...Loconto SHORT TERM...Loconto LONG TERM...KP AVIATION...Loconto/KP MARINE...Loconto/KP
Hazardous Weather Outlook National Weather Service Boston/Norton MA 429 AM EDT Sun Aug 13 2023 CTZ002>004-MAZ002>024-026-RIZ001>008-140830- 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- 429 AM EDT Sun Aug 13 2023 This Hazardous Weather Outlook is for northern Connecticut, all of Massachusetts east of Berkshire County, and Rhode Island. .DAY ONE...Today and tonight. A few strong to severe thunderstorms are possible this morning, mainly near the south coast and in eastern MA. Damaging wind and large hail are the primary threats. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. ANZ230>237-250-251-254>256-140830- 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- 429 AM EDT Sun Aug 13 2023 This Hazardous Weather Outlook is for Massachusetts and Rhode Island coastal waters. .DAY ONE...Today and tonight. A few strong thunderstorms with gusty wind and hail are possible this morning, mainly over the south coastal waters. .DAYS TWO THROUGH SEVEN...Monday through Saturday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. 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/NWSBoston You can follow us on Twitter at @NWSBoston
Special Weather Statement
National Weather Service Boston/Norton MA
909 AM EDT Sun Aug 13 2023
MAZ018>022-131345-
Eastern Plymouth MA-Southern Bristol MA-Southern Plymouth MA-
Western Plymouth MA-Barnstable MA-
909 AM EDT Sun Aug 13 2023
...A strong thunderstorm will impact portions of southwestern
Barnstable, southeastern Plymouth and southeastern Bristol Counties
through 945 AM EDT...
At 909 AM EDT, Doppler radar was tracking a strong thunderstorm over
New Bedford, moving east at 30 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Strong winds could cause minor damage such as downed
branches.
Locations impacted include...
New Bedford, Fall River, Plymouth, Dartmouth, Falmouth, Marion,
Middleborough, Wareham, Sandwich, Bourne, Fairhaven, Mashpee, Carver,
Acushnet, Freetown, Mattapoisett, and Rochester.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Get indoors when you hear thunder. Do not resume outdoor activities
until at least 30 minutes after the storm has passed.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. For your
safety, go indoors or to your vehicle.
This storm may intensify and become severe. Stay tuned to your local
media for updates and possible warnings.
&&
LAT...LON 4163 7049 4161 7070 4165 7069 4160 7078
4157 7101 4174 7108 4189 7059
TIME...MOT...LOC 1309Z 254DEG 27KT 4168 7096
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
KSSpecial Weather Statement
National Weather Service Boston/Norton MA
913 AM EDT Sun Aug 13 2023
MAZ020-022-023-131400-
Southern Bristol MA-Dukes MA-Barnstable MA-
913 AM EDT Sun Aug 13 2023
...A strong thunderstorm will impact portions of northern Dukes,
southern Barnstable and southeastern Bristol Counties through 1000 AM
EDT...
At 913 AM EDT, Doppler radar was tracking a strong thunderstorm over
Gosnold, or 9 miles west of Tisbury, moving east at 40 mph.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Strong winds could cause minor damage such as downed
branches. Little to no impact from hail is expected.
Locations impacted include...
Barnstable, Dartmouth, Falmouth, Brewster, Oak Bluffs, Edgartown,
Tisbury, Aquinnah, Yarmouth, Sandwich, Bourne, Fairhaven, Dennis,
Mashpee, Harwich, West Tisbury, Chilmark, Gosnold, and Hyannis.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Get indoors when you hear thunder. Do not resume outdoor activities
until at least 30 minutes after the storm has passed.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. For your
safety, go indoors or to your vehicle.
This storm may intensify and become severe. Stay tuned to your local
media for updates and possible warnings.
&&
LAT...LON 4166 7007 4151 7058 4142 7050 4133 7086
4138 7077 4145 7073 4139 7090 4147 7095
4151 7082 4155 7086 4149 7096 4155 7100
4164 7071 4155 7085 4152 7082 4152 7080
4155 7071 4165 7068 4178 7015
TIME...MOT...LOC 1313Z 250DEG 37KT 4150 7079
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
KSSpecial Weather Statement
National Weather Service Boston/Norton MA
1250 PM EDT Sun Aug 13 2023
CTZ003-MAZ010-011-131730-
Tolland CT-Eastern Hampden MA-Eastern Hampshire MA-
1250 PM EDT Sun Aug 13 2023
...A strong thunderstorm will impact portions of northern Tolland,
south central Hampshire and south central Hampden Counties through
130 PM EDT...
At 1249 PM EDT, Doppler radar was tracking a strong thunderstorm over
West Springfield, moving east at 10 mph.
HAZARD...Very slow moving storms producing rainfall rates as high as
1 inch per hour may result in localized urban and poor
drainage, minor flooding.
SOURCE...Radar indicated.
IMPACT...Minor nuisance flooding of typically flood prone areas.
Locations impacted include...
Springfield, Chicopee, Westfield, Holyoke, Agawam, West Springfield,
Ludlow, South Hadley, Longmeadow, East Longmeadow, Belchertown,
Wilbraham, Somers, Southwick, Granby, Southampton, and Hampden.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Get indoors when you hear thunder. Do not resume outdoor activities
until at least 30 minutes after the storm has passed.
Do not drive through flooded roads or underpasses. Avoid low lying
areas near small streams.
&&
LAT...LON 4229 7243 4203 7241 4204 7273 4218 7276
TIME...MOT...LOC 1649Z 261DEG 8KT 4211 7265
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...<30 MPH
KSSpecial Weather Statement
National Weather Service Boston/Norton MA
144 PM EDT Sun Aug 13 2023
MAZ023-024-131845-
Nantucket MA-Dukes MA-
144 PM EDT Sun Aug 13 2023
...A strong thunderstorm will impact portions of Nantucket and
southeastern Dukes Counties through 245 PM EDT...
At 143 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles south of Edgartown, moving east at 35 mph.
HAZARD...Winds in excess of 40 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Strong winds could cause minor damage such as downed
branches. Minor damage to outdoor objects is possible.
Locations impacted include...
Nantucket and Edgartown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Get indoors when you hear thunder. Do not resume outdoor activities
until at least 30 minutes after the storm has passed.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. For your
safety, go indoors or to your vehicle.
This storm may intensify and become severe. Stay tuned to your local
media for updates and possible warnings.
&&
LAT...LON 4124 6994 4122 7013 4129 7030 4136 7033
4135 7042 4133 7042 4132 7066 4138 7042
4132 7012 4142 7004 4129 6994
TIME...MOT...LOC 1743Z 254DEG 29KT 4126 7053
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
KSSpecial Weather Statement
National Weather Service Boston/Norton MA
243 PM EDT Sun Aug 13 2023
CTZ004-MAZ012-013-RIZ001-131945-
Windham CT-Southern Worcester MA-Western Norfolk MA-
Northwest Providence RI-
243 PM EDT Sun Aug 13 2023
...A strong thunderstorm will impact portions of northeastern
Windham, southeastern Worcester, west central Norfolk and
northwestern Providence Counties through 345 PM EDT...
At 242 PM EDT, Doppler radar was tracking a strong thunderstorm over
Southbridge, or 17 miles southwest of Worcester, moving east at 35
mph.
HAZARD...Winds in excess of 40 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Strong winds could cause minor damage such as downed
branches. Minor damage to outdoor objects is possible.
Locations impacted include...
Woonsocket, Milford, Webster, Southbridge, Bellingham, Burrillville,
Northbridge, Oxford, Uxbridge, Charlton, North Smithfield, Dudley,
Thompson, Sturbridge, Blackstone, Sutton, Douglas, Woodstock, Upton,
and Hopedale.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Get indoors when you hear thunder. Do not resume outdoor activities
until at least 30 minutes after the storm has passed.
&&
LAT...LON 4201 7205 4213 7205 4215 7149 4197 7149
TIME...MOT...LOC 1842Z 269DEG 32KT 4206 7199
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH
FieldThe Boston radar (KBOX), 115 km away, was scanning. The volume nearest the first event began at 18:47 UTC.
5 thunderstorm wind, 1 lightning. Local standard time, as filed.
In Nantucket, a house was struck by lightning on Goose Pond Ln. Shingles on the roof were thrown off by the strike.
On Nantucket, although the worst part of the storm passed just offshore to the north, on Jetties Beach tables were overturned and umbrellas broken at a restaurant. One person was hit by flying debris but not injured. Also, the fire department reported a tree down blocking Goose Pond Ln.
In Norton, there was a tree down in the vicinity of Burt St.
In Easton, powerlines were downed on Old Farm Rd.
In Raynham, powerlines were downed in the vicinity of Broadway.
In Middleborough, trees were downed partially blocking Vernon St.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Massachusetts in 2023Every state in 2023This day in weather historyWarnings in Massachusetts, August 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1119887, 1119889, 1119888, 1119890, 1119891, 1119893.