A warm front lifting slowly northward across Connecticut and into Massachusetts helped trigger a few marginally severe thunderstorms in western and central Massachusetts in the early afternoon.
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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.
A warm front lifting slowly northward across Connecticut and into Massachusetts helped trigger a few marginally severe thunderstorms in western and central Massachusetts in the early afternoon.
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 27, 9:11 AM EST, 3 hours 35 minutes earlier.
Area Forecast Discussion National Weather Service Boston/Norton MA 1011 AM EDT Thu Aug 27 2020 .SYNOPSIS... Scattered showers and thunderstorms will develop today as a warm front moves into the region, with a risk of severe storms mainly across southwest New England. Dry and warm weather briefly returns to the area Friday before more showers and thunderstorms return Saturday afternoon and night ahead of an approaching cold front. Drier, less humid and cooler weather returns Sunday into early next week, with a taste of fall featuring mild days and cool nights. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM Update... So far this morning southern New England has had considerable cloudiness in response to low/mid level jet exiting the Great Lakes and associated WAA. The associated showers falling have been falling into an airmass with dew pts in the upper 40s and low 50s, which so far has limited rain reaching the ground/evaporative cooling. Noting on radar that increased shower development is occurring upstream and along/north of the warm front, current forecast indicates this potential for showers through midday, with t-storms possible in western MA and northern CT. Early morning forecast indicates this so only making minor adjustments to forecast with this update. *** Scattered severe thunderstorms possible this afternoon, with the greatest risk across CT and adjacent areas in SW MA and southern RI *** Modest moisture transport and decreasing stability and a weakening MCS will result in scattered showers moving across SNE this morning. These showers moving into an airmass with dewpoints in the 40s will help to lock in a chilly airmass especially in northern MA which may be tough to dislodge. A warm front is expected to lift north into SNE from the SW and the position of this front will be critical to severe weather potential. Minimal to no surface-based CAPE expected to the north of the boundary while to the south CAPES will increase to 1000-2000 J/kg. There remains some uncertainty with the northward extent of the boundary but it is looking increasingly likely that the front remains south of the Mass Pike somewhere near the CT/MA border and it is still possible it could end up even further south across CT. Where the boundary sets up with axis of best instability is important as the environment will be highly sheared as strong mid level W/NW flow aloft will result in deep layer shear 50-55 kt with SNE within the right entrance region of the upper jet. Instability/shear parameter space supports organized storms with supercells possible. Damaging wind and very large hail may accompany any supercells and a few tornadoes are possible given impressive hodographs showing strong low level shear and helicity. Warm fronts are always a concern in a highly sheared environment. Locally heavy rainfall also a threat south of the Pike with PWATs up to 1.75". The best chance for a high end severe event with supercells will be south of a BAF-PVD line and particularly across CT. This is where HREF is targeting axis of updraft helicity. Hi-res CAMs indicating a W-E line of storms in NY which is expected to extend east into SNE and move south across SW MA/CT and possibly into RI mid/late afternoon. However, it is important to note that the main axis of severe weather may still shift further south and end up mostly south of BOX CWA where better mid level lapse rates are forecast with the remnant EML. Will have to monitor the instability trends and the location of the warm front. Enough elevated instability north of the boundary to support a few t-storms across northern MA but severe threat is much lower here due to stable boundary layer with just the risk of mostly sub-severe hail. Temperature forecast is very tricky and dependent on where the warm front sets up. North of the boundary, it may be rather chilly with temps likely remaining in the 60s and may even fall into the upper 50s especially in northern MA. While to the south of the front, temps should reach into the 80s with best chance across the lower CT valley in CT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Tonight... Lingering showers and t-storms possible south of the Pike which will move south of the coast in the evening. Otherwise, may see areas of stratus and fog develop during the night. Lows will range from mid 50s to lower 60s. Friday... Weak shortwave ridging moves in combined with drying in the column will result in sunshine developing after any low clouds burn off. 850 mb temps 13-15C support highs in the 80s with moderate humidity levels. Local sea breezes may develop which will keep it a bit cooler along the immediate coast. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Highlights * Tropical downpours possible Sat/Sat night as moisture from remnants of Laura stream northward. A few strong-severe storms possible as well * Drying trend Sunday and turning less humid * Fall-like weather early next week with mild days and cool nights Precipitation... Dry weather lingers thru the first half of Fri night, but then scattered showers/T-storms possible toward Saturday morning as warm front approaches the region. As parent low pressure tracks thru northern NY, warm front should lift thru southern New England with warm sector overspreading the region Sat afternoon. Although this may not be a clean warm sector with BKN-OVC conditions along with scattered showers/T-storms. With dew pts climbing to 70-75 not surprised the ECENS offering 70-90% probs of CAPEs exceeding 1000 j/kg. Fairly strong mid level winds around 45 kt at 500 mb. Thus CAPE/Shear profiles suggest at least a low prob for a few strong to severe storms as cold front approaches late in the day. This agrees with SPC new day3 outlook...a marginal risk across MA/RI/CT and a slight risk up to NYC. In addition, tropical moisture from the remnants of Laura begin to stream northward and interact with frontal boundary. Ensembles indicating PWATs of 2+ inches Sat/Sat night. This combined with large scale ascent from RRQ of 90 kt jet streak streaming across New England late Sat/Sat night should support some tropical downpours. ECENS indicates up to 60% probs of 1+ of localized rainfall. By Sunday post frontal airmass overspreads the region with significant column drying as ensembles show PWATs falling below 1 inch. The only exception will be Cape Cod and Nantucket that may see showers linger into early Sunday morning before dry weather arrives for the afternoon. Dry weather then prevails Monday/Tuesday and possibly into mid week but return flow may yield a risk of rain/showers by then. Temperatures... Strong WAA Saturday with 925 mb temps warming to about +22C over southern New England. Typically this would offer highs 85-90 but as mentioned above there will likely be an abundance of clouds and showers/T-storms Saturday. This should limit highs to the upper 70s and lower 80s. However it will feel warm and very humid as dew pts climb to 70-75 as tropical moisture from remnants from Laura overspread the area. By Sunday, post frontal with rapid drying thru the column, supporting sunshine and much less humid as dew pts fall into the 50s. Temps aloft of +17C at 925 mb and +10C at 850 mb will support highs of 75-80. Really spectacular weather Sunday and continuing into Monday as short wave ridging and high pressure builds over the area. In fact a touch of fall in the air Monday morning with both ensembles and deterministic guidance offering +6C to +7C air at 850 mb over southern New England! Therefore expect mid days with highs in the 70s and cool nights with lows in the 50s, possibly some 40s. This dry/fall-like weather likely lingers into Tue with return flow possibly setting by mid week, thus trending warmer/more humid possibly. * && .AVIATION /14Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 14z update... Today...Moderate confidence. VFR during late morning with areas of MVFR cigs developing during this afternoon as scattered morning showers move through. Areas of IFR cigs possible. Risk for strong to severe storms mid/late afternoon, with the greatest risk across CT and adjacent portions of MA south of the Pike. Tonight...Moderate confidence. Areas of MVFR/IFR stratus and patchy fog may develop but extent of coverage is uncertain. Lingering showers/t-storms exit the south coast in the evening. Friday...High confidence. Any lingering MVFR/IFR early will quickly become VFR. KBOS Terminal...Moderate confidence in TAF. A t-storm is possible in the afternoon but greater risk will be south and west of BOS. KBDL Terminal...Moderate confidence in TAF. Strong to severe t-storms may impact BDL mid/late afternoon. Outlook /Friday Night through Monday/... Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA, chance TSRA. Saturday: MVFR/IFR conditions possible. Breezy. SHRA likely, chance TSRA, patchy FG. Saturday Night: Mainly VFR, with local IFR possible. Breezy. Chance SHRA, chance TSRA, patchy BR. Sunday: VFR. Breezy. Sunday Night through Monday: VFR. && .MARINE... Winds and seas will remain below SCA thresholds today. While winds are light tonight increasing southerly swell may result in seas approaching 5 ft over southern waters. A SCA may be needed tonight. Light winds and seas below SCA Fri. Scattered t-storms possible mid/late afternoon into the evening, especially over south coastal waters. Outlook /Friday Night through Monday/... Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, chance of thunderstorms, patchy fog. Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain showers likely, chance of thunderstorms, patchy fog. Saturday Night: Winds less than 25 kt. Local rough seas. Chance of rain showers, chance of thunderstorms, patchy fog. Sunday through Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Monday: Winds less than 25 kt. Areas of seas approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && SYNOPSIS...KJC/Nocera NEAR TERM...KJC/Nocera/NMB SHORT TERM...KJC LONG TERM...Nocera AVIATION...KJC/Nocera MARINE...KJC/Nocera
Hazardous Weather Outlook National Weather Service Boston/Norton MA 427 AM EDT Thu Aug 27 2020 CTZ002>004-MAZ002>024-026-RIZ001>008-280830- 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- 427 AM EDT Thu Aug 27 2020 This Hazardous Weather Outlook is for northern Connecticut, all of Massachusetts east of Berkshire County, and Rhode Island. .DAY ONE...Today and tonight. Scattered strong to severe thunderstorms are possible mid to late afternoon, with greatest risk across CT and adjacent areas of southwest MA and southern RI. Damaging wind and large hail are the primary threat, and an isolated tornado or two is possible. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. ANZ230>237-250-251-254>256-280830- 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- 427 AM EDT Thu Aug 27 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...Friday through Wednesday. 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/us.nationalweatherservice.boston.gov You can follow us on Twitter at @NWSBoston
The Albany radar (KENX), 122 km away, was scanning. The volume nearest the first event began at 17:48 UTC.
5 thunderstorm wind, 2 flood. Local standard time, as filed.
In Northampton, a tree was down on Interstate-91 northbound.
In Belchertown, a tree was down on power lines on Rockrimmon Street and a tree was down on Boardman Street.
In West Brookfield, a large tree and wires were down at the three-way intersection of Southbridge Road, Webber Road, and Brookfield Road.
In Worcester, flooding was reported on Whipple Street at Blackstone River Road with manhole covers floating. Also, flooding was reported on College Street at Southbridge Street.
In the Fiskdale section of Sturbridge, a tree was down on the southbound side of Route 148.
In the southeast part of Worcester, law enforcement reported that several cars were stuck in flooding on Route 20 at the 86 Cutoff. A few rescues of people were being conducted.
In Holliston, a tree and wires were down on Burnap Road. Also, a tree was down on wires on Highland Street.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Massachusetts in 2020Every state in 2020This day in weather historyWarnings in Massachusetts, August 2020
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: 916715, 916720, 916729, 916702, 916732, 916713, 916733.