A mid atmospheric disturbance moved over a unstable airmass across northern Vermont during the afternoon hours of July 4th. Scattered thunderstorms rotated north to southeast across the region, some of them providing localized damaging 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 BTV wrote it up.
A mid atmospheric disturbance moved over a unstable airmass across northern Vermont during the afternoon hours of July 4th. Scattered thunderstorms rotated north to southeast across the region, some of them providing localized damaging winds.
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 Burlington, VT wrote its last area forecast discussion before the first event at Jul 4, 12:41 PM EST, 1 hour 12 minutes earlier.
Area Forecast Discussion National Weather Service Burlington VT 141 PM EDT Tue Jul 4 2023 .SYNOPSIS... Seasonably warm and humid conditions will continue for Independence Day with chances of showers and a few thunderstorms under the influence of an upper level trough. Localized heavy rainfall and dangerous lightning will be primary hazards with thunderstorms. After the holiday, temperatures will trend hot for Wednesday and Thursday while conditions remain humid, resulting in heat stress concerns. More showers and thunderstorms are expected for Friday into the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... As of 141 PM EDT Tuesday...Showers and isolated thunderstorms continue to develop, dissipate, and redevelop across the region, mainly from the Adirondacks eastward with lake breezes keeping precipitation mainly away from the Champlain Valley. Convective activity has been ever so slightly shifting southward and will continue to do so this afternoon with the primary focus being along and south of Route 2 in VT, and a secondary focus over the Adirondacks though much more isolated. Upstream vigorous thunderstorms continue over Montreal and with a slow drift south could affect border towns later this afternoon, but we expect the intensity to diminish as it does so. Otherwise, it's a very warm and humid day with temps warming above previous forecast highs into the mid/upper 80s and dewpoints holding in the mid/upper 60s. For tonight, shower activity will wane with the loss of surface heating and instability. Fog will quickly replace the showers after sunset where rain occurred and will be locally very dense in the river valleys, especially across VT. No big airmass change, so conditions will continue to be oppressive with overnight lows only in the 60s and dewpoints just a degree or two below. Can't rule out a few showers and thunderstorms over terrain as temperatures trend warmer Wednesday. Temperatures and humidity will combine to produce heat indices in the low to mid 90s warranting an increase in concerns for heat illness to those unprepared. Expect to need additional hydration especially if you'll be outdoors. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/... As of 322 AM EDT Tuesday...Deep layer ridging will be overhead Wednesday night into Thursday morning. However, surface dewpoints will remain in the mid 60s for most locations, and with a light south wind beginning to develop. So a warm start is expected Thursday morning. The heat is only expected to crank up further during the day as the ridge amplifies to our east, and continues to drive warm, moist air into the region. 925hPa temperatures will be around 24 or 25 C. Upper 80s in eastern Vermont and the Adirondacks, and low to mid 90s in the broader valleys, along with continued humid, but not oppressive, dewpoints in the low to mid 60s will result in heat indices around 92 to 96 in our warmer locations. Heat advisories may be necessary. We have some "low- hanging fruit" on the record books, with several climate sites within 1 to 4 degrees of their daily record highs in the low to mid 90s. During the afternoon, only isolated showers and thunderstorms are expected. Warm, dry subsidence aloft will likely cap convection. Even when the cap breaks mid-afternoon, even the regional models are not enthusiastic about vertical motions until sunset, and as we lose the best diurnally driven instability. There will be a light southerly breeze, but probably not persistent enough to offer much relief. Best chances for rain on Thursday will probably be between 5 PM and midnight at 20-30%, mainly for higher terrain areas. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 322 AM EDT Tuesday...A prefrontal trough will approach the region Thursday night into Friday morning. So we should have some showers on the scope, with elevated convection developing from a modest 20 to 30 knot LLJ and an approaching right entrance region of a weak 70-80 knot 250 jet extending from the Great Lakes up into Canada to allow efficient moisture transport. The increasing clouds and humidity will probably keep low temperatures in the 60s across the region, with typical warm spots like BTV failing to fall below 70. By Friday midday, a surface low will track well north of Montreal, and frontal forcing really begins to stretch itself out as the low pulls far away from Vermont and northern New York. In combination with the prefrontal trough, this will help to limit instability and convergence across the region. However, if there are breaks of partial sunlight, there could be some small scale organization of storms amidst about 30 knots of 0-6 km shear ahead of the front. The best potential appears to be far eastern Vermont into New Hampshire and western Maine where 7 to 8 C mid-level lapse rates also are forecast to reside, but will continue to monitor if the system slows down. More abundant clouds should hold temperatures in the mid 80s west, and some upper 80s east. Once that front clears the area on Saturday, our weather turns a bit cooler. Although still on the warm side, it looks like we avoid overly hot conditions. While guidance is in decent agreement temperaturewise, the outlook for precipitation shows active weather, but to varying degrees. Trying to parse things out, this is the general appearance of how things are laid out. Saturday, a thin plume of Gulf moisture will traverse along the frontal boundary, creating a sharp density boundary across New England as a subtle shortwave tracks up the St. Lawrence Valley. This will help to spark some activity. The best chances will be south and east, perhaps including Vermont in that strip of greater dewpoint contrast with forcing from the shortwave. Sunday, models are in disagreement on the exact features overhead, but almost all depict some kind of shower activity. Then by next Monday and next Tuesday, a deep upper low will move towards the Hudson Bay in Canada, and help pinwheel embedded features our direction in broad cyclonic flow, but at least keep us a bit cooler. We'll have to see if an particular system lines up to produce stronger low-level confluence along the periphery of high latitude blocking for any heavy rainers early next week. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... Through 18Z Wednesday...VFR conditions will generally prevail through the remainder of the daylight hours with scattered showers and thunderstorms diminishing towards sunset. Brief MVFR/IFR is likely if any storms move directly over a terminal, and will handle with amendments. After 00Z, expect areas of fog to develop again for the overnight, with high confidence at KSLK and KMPV. Have mention of VCFG elsewhere where confidence is lower, though if any terminal gets rain this afternoon, the probability of fog will increase. Wednesday will be a rinse and repeat of today though with less areal coverage of convection, and mainly VFR again. Winds will be light northerly less than 8kts this afternoon, near calm overnight, then WNW less than 8kts tomorrow. Outlook... Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. Likely SHRA, Slight chance TSRA. Friday Night: Mainly VFR, with local IFR possible. Chance SHRA, Slight chance TSRA. Saturday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Saturday Night: VFR. Slight chance SHRA. Sunday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. && .HYDROLOGY... WPC continues to have the region under Marginal Risk for excessive rainfall. Given the moist air currently being transported to the region, the threat of heavier rainfall continues to exist in any deeper convection that develops. With the extremely wet antecedent conditions, as well as recent flooding that has occurred, there continues to be a threat of more localized flooding. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && SYNOPSIS...Boyd NEAR TERM...Boyd/Lahiff SHORT TERM...Haynes LONG TERM...Haynes AVIATION...Lahiff HYDROLOGY...Kremer
Hazardous Weather Outlook National Weather Service Burlington VT 423 AM EDT Tue Jul 4 2023 NYZ026>031-034-035-087-VTZ001>011-016>021-050830- Northern St. Lawrence-Northern Franklin-Eastern Clinton- Southeastern St. Lawrence-Southern Franklin-Western Clinton- Western Essex-Eastern Essex-Southwestern St. Lawrence-Grand Isle- Western Franklin-Orleans-Essex-Western Chittenden-Lamoille-Caledonia- Washington-Western Addison-Orange-Western Rutland-Eastern Franklin- Eastern Chittenden-Eastern Addison-Eastern Rutland-Western Windsor- Eastern Windsor- 423 AM EDT Tue Jul 4 2023 This Hazardous Weather Outlook is for northern New York, central Vermont, northeast Vermont, northwest Vermont and southern Vermont. .DAY ONE...Today and tonight. The probability for widespread hazardous weather is low. Isolated to scattered thunderstorms are again expected today with a rare cell possibly becoming strong in the 2-6PM time frame. Those outdoors for Independence Day festivities will want to have a plan in case of lighting. .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.
Special Weather Statement
National Weather Service Burlington VT
230 PM EDT Tue Jul 4 2023
VTZ003-007-008-041900-
Caledonia VT-Washington VT-Orleans VT-
230 PM EDT Tue Jul 4 2023
...A strong thunderstorm will impact portions of west central
Caledonia, southern Orleans and northeastern Washington Counties
through 300 PM EDT...
At 229 PM EDT, Doppler radar was tracking a strong thunderstorm over
Hardwick. This storm was nearly stationary.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Walden, Hardwick, Stannard, Greensboro Bend, Greensboro, Wheelock,
Danville, East Greensboro, North Walden, South Walden, East Hardwick,
and Hardwick Center.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4453 7238 4459 7229 4453 7208 4442 7222
TIME...MOT...LOC 1829Z 308DEG 2KT 4452 7230
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
KutikoffThe Burlington radar (KCXX), 68 km away, was scanning. The volume nearest the first event began at 18:53 UTC.
5 thunderstorm wind, 3 hail. Local standard time, as filed.
Multiple trees downed by thunderstorm winds in East Hardwick, including Route 16 and Cedar street.
Multiple trees reported down on East Shore Road and Park.
Dime to quarter size hail reported.
Dime to quarter size hail reported.
Additional trees downed by thunderstorm winds from a second round of thunderstorms.
Several trees downed by thunderstorm winds.
Trees and branches on power lines.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Vermont in 2023Every state in 2023This day in weather historyWarnings in Vermont, July 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: 1125513, 1125508, 1125515, 1125509, 1125510, 1125517, 1125521, 1125525.