In the midst of record heat a weak short wave east of a more elongated trough axis moved through southern New England bringing scattered showers and thunderstorms in the evening. Dewpoints were in the low 70s with steep mid-level lapse rates and robust instability thanks to the warm and moist airmass.
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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.
In the midst of record heat a weak short wave east of a more elongated trough axis moved through southern New England bringing scattered showers and thunderstorms in the evening. Dewpoints were in the low 70s with steep mid-level lapse rates and robust instability thanks to the warm and moist airmass.
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 Sep 7, 5:53 PM EST, 2 hours 22 minutes earlier.
Area Forecast Discussion
National Weather Service Boston/Norton MA
653 PM EDT Thu Sep 7 2023
.SYNOPSIS...
Very warm and humid weather continues into Friday, although not
record breaking like Thursday. Not as hot this weekend into Monday,
but warmer than normal along with humid conditions. Scattered
thunderstorms with heavy rain may impact western portions of
Massachusetts & Connecticut Friday afternoon & evening. This trend
continues into the weekend and Monday, with storms most numerous
well inland. Somewhat drier and less humid conditions may arrive
around Tuesday, but will be short lived as the risk for showers and
thunderstorms increase mid week, followed by a drying trend arrives
late next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
645 PM update...
Very warm and humid evening in progress across SNE. Dew pts in
the low 70s and a light southwest breeze will yield lows only in
the upper 60s and lower 70s overnight. The normal overnight low
for this time of year is in the upper 50s and lower 60s, about
10 degs warmer than normal. Fog bank southeast of Nantucket
should remain at bay this evening, given SSW low level winds.
However, with dew pts in the low 70s along the south coast and
over the ocean south of MA/RI, expecting patchy fog and low
clouds to develop overnight and advance northward onshore.
Convection firing across northeast PA, northwest NJ into
southeast NY, will advect northeast into western MA later this
evening, but in a weaken state as SB instability wanes and deep
layer shear and mid level lapse rates remain marginal. Threat
for severe weather in western MA is low, with a higher
probability of gusty winds and locally heavy rain. For the
remainder of the region, mainly dry weather prevails overnight.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
After a lull in the unsettled weather tonight and Friday morning the
trough axis inches a bit closer to SNE (crossing the eastern Great
Lakes) which will shift the stronger forcing a bit closer to our
region and increase the coverage/potential of convection east into
our western/central MA and CT zones. The HREF shows that while the
swath of strongest updraft helicity (a proxy for severe weather) is
over eastern NY today, it shifts into the western portion of our
county warning area. Bulk shear values are quite weak (25 kts) but
could very well be made up for by the very high amount of
instability. CAPE values will be on the order of 2,000-3000 J/km
with lapse rates of 6-8C/km. Thus, the SPC's Slight risk has been
shifted east into central MA/western CT. The window for convection
seems to be between 2pm and 10pm. Showers and storms taper off
overnight but we've got no real airmass change (i.e. no dry airmass
moving in) so humidity and the chance for scattered showers sticks
around Friday night. Speaking of temperatures, Friday is the last
day of our Heat Advisory; don't expect temperatures as hot as today
(more like the upper 80s) but given the very humid airmass it will
still feel as warm as the upper 90s in places like the CT and
Merrimack Valleys.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
340 PM update...
Key Points...
* Not as hot but still humid Sat/Sun/Mon with scattered showers and
t-storms at times, with locally heavy rain likely
* Somewhat lower humidity with seasonable temps around Tue, but
another round of showers is possible mid to late next week
Details...
Saturday/Sunday/Monday...
Not as hot but remaining warmer than normal along with humid
conditions, as ridging with above normal heights and 850 mb temps
linger over New England thru the weekend into Monday. Expecting
highs in the low to mid 80s Saturday, upper 70s to lower 80s Sunday
and 75-80 Monday. While highs slowly lower each day, dew pts remain
70-75 each day, thus very humid conditions for early to mid Sep. As
for precip chances, New England remains under SW flow aloft
Sat/Sun/Mon. Saturday, there are subtle height rises with ridge
building back to the NW, yielding a decrease in shear Sat. This may
yield lower precip chances than Sunday, when subtle height falls and
increasing shear from approaching s/wv energy occur Sunday.
Although, it won't take much forcing to produce scattered showers
and storms any of these days given the instability and anomalous
moisture. This will combine to yield storms with heavy rain
potential. Something we will have to watch moving forward.
Tuesday/Wednesday/Thursday...
Ensembles indicate potential short wave ridging and slightly
lowering PWATs behind departing trough around Tuesday, hence perhaps
supporting a period of slightly drier and less humid weather.
However, it's short lived as anomalous trough moves across the Great
Lakes mid week and into the New England late week. Thus, increasing
the chance of showers/thunderstorms and a return toward more humid
conditions.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z TAF Update...
Not much change from previous thinking, VFR and dry weather at
00z, slowly declining to IFR/LIFR by daybreak Friday for most
terminals. Any showers and thunderstorms later this evening
should be confined to western MA. Light SSW winds overnight.
Earlier discussion below.
------------------------------------------------------------------
Tonight...Moderate Confidence.
VFR. Low probability risk for a shower/t-storm in far western
MA/western CT. Widespread IFR-LIFR conditions will return over a
greater area tonight with fog and low clouds, especially over
RI/SE MA. Light SSW winds.
Friday...High Confidence
VFR north of RI/CT border after any fog patches burn off by mid
morning. IFR/LIFR early should improve to more MVFR conditions
further south closer to the coast. Winds SW 5 to 10 knots with
some afternoon showers and thunderstorms developing west of
I-495.
Friday night...Moderate Confidence.
Any lingering showers/t-storms will generally die off after
sunset but can't rule out a spot shower/t-storm during the
evening/early overnight. S winds 5kt.
KBOS TAF...High confidence in TAF.
KBDL TAF...High confidence in TAF.
Outlook /Saturday through Tuesday/...
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA,
isolated TSRA.
Saturday Night: VFR. Chance SHRA, isolated TSRA.
Sunday through Sunday Night: Mainly VFR, with local MVFR
possible. Chance SHRA, isolated TSRA.
Monday: Mainly VFR, with areas MVFR possible. SHRA likely,
isolated TSRA.
Monday Night: Mainly VFR, with local IFR possible. Chance SHRA,
isolated TSRA.
Tuesday: Mainly VFR, with local IFR possible. Slight chance
SHRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Today through Friday night...
Calm and tranquil conditions persist over the coastal waters
through Friday night with high pressure supporting light
southerly winds and seas generally 1 to 2 feet.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt.
Saturday Night: Winds less than 25 kt. Slight chance of rain
showers.
Sunday: Winds less than 25 kt. Slight chance of rain showers,
isolated thunderstorms.
Sunday Night: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.
Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers, isolated thunderstorms.
Monday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers, isolated thunderstorms.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
&&
.CLIMATE...
Record High Today, September 7th:
Boston: 102 in 1881
Providence: 96 in 1983
Hartford: 95 today/2023, previous record 93 in 2015
Worcester: 90 in 1945 & today/2023!
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Friday for CTZ002>004.
MA...Heat Advisory until 8 PM EDT Friday for MAZ003>006-010>013-017-
026.
RI...Heat Advisory until 8 PM EDT Friday for RIZ001-002-004-005.
MARINE...None.
&&
SYNOPSIS...Nocera/BW
NEAR TERM...Nocera/BW
SHORT TERM...BW
LONG TERM...Nocera
AVIATION...Nocera/BW
MARINE...Nocera/BW
CLIMATE...StaffThe Albany radar (KENX), 89 km away, was scanning. The volume nearest the first event began at 01:16 UTC.
8 thunderstorm wind. Local standard time, as filed.
In Worthington, a tree was down on powerlines near Old North Rd.
In Huntington, there was a tree down on County Rd.
In Russell, there was a tree down near Dickinson Hill Rd.
In Rowe, there was a tree and wires down on Pond Rd.
In Charlemont, there was a tree down blocking South River Rd.
In Hawley, there was a tree down on West Hawley Rd.
In Deerfield, there was a tree down on wires on Stillwater Rd.
In Montague, there was a tree down at the intersection of Meadow Rd and South Ferry Rd.
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, September 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: 1121328, 1121329, 1121330, 1121331, 1121332, 1121333, 1121334, 1121335.