A weak low pressure system approached Western New Hampshire with southerly flow ahead of the feature advecting abundant moisture and instability into the region ahead of it. Cool upper levels allowed for thunderstorms to quickly develop by midday with the atmosphere supporting large hail formation and gusty outflow convective 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 GYX wrote it up.
A weak low pressure system approached Western New Hampshire with southerly flow ahead of the feature advecting abundant moisture and instability into the region ahead of it. Cool upper levels allowed for thunderstorms to quickly develop by midday with the atmosphere supporting large hail formation and gusty outflow convective winds. Storms quickly become severe in Grafton and Sullivan Counties by early afternoon. Many hail and wind damage reports were received across this area during the afternoon hours.
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 Gray, ME wrote its last area forecast discussion before the first event at Aug 4, 11:44 AM EST, 1 hour 12 minutes earlier.
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</html>The Burlington radar (KCXX), 107 km away, was scanning. The volume nearest the first event began at 17:57 UTC.
4 thunderstorm wind, 3 hail. Local standard time, as filed.
Convective outflow winds from a severe thunderstorm downed trees on River Rd. near the Lyme-Orfordville town line.
A severe thunderstorm dropped hail the size of half dollars north of Lyme, New Hampshire.
A severe thunderstorm dropped hail the size of ping pongs south of Claremont, New Hampshire.
Convective outflow winds from a severe thunderstorm downed trees south of Claremont, New Hampshire.
A severe thunderstorm dropped hail the size of half dollars in Claremont, New Hampshire.
Convective outflow winds from a severe thunderstorm downed numerous trees in the town of Gantham along Interstate 89.
Convective outflow winds from a severe thunderstorm downed multiple trees on North Pinkham Rr. between Unity and Lempster New Hampshire.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New Hampshire in 2023Every state in 2023This day in weather historyWarnings in New Hampshire, 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 2026-09-30. Each event’s entry at NCEI: 1138576, 1138575, 1138578, 1138581, 1138580, 1138583, 1138582.