Record May Heat produced the instability and the mountains of the Green Mountains produced the lift to develop thunderstorms in the afternoon that very slowly moved south to north along the mountain ridges. A few storms produced wet micro-bursts that caused some tree and utility line damage.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
Record May Heat produced the instability and the mountains of the Green Mountains produced the lift to develop thunderstorms in the afternoon that very slowly moved south to north along the mountain ridges. A few storms produced wet micro-bursts that caused some tree and utility line damage.
In addition, Record Heat was observed in VT. Daily record highs for May 27th included; Burlington at 95 degrees, Montpelier at 91 degrees, St. Johnsbury at 92 degrees and the summit of Mount Mansfield at 85 degrees.
Burlington's high temperature was the hottest May day since records began in 1883 and the low of the day (72 degrees) was the warmest ever in May. Mount Mansfield recorded it's warmest temperature EVER at 85 degrees since records began in November 1954. Montpelier's 91 degree high was it's warmest day in May since records began in 1949.
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 May 27, 5:45 AM EST, 1 hour 15 minutes earlier.
Area Forecast Discussion National Weather Service Burlington VT 645 AM EDT Wed May 27 2020 .SYNOPSIS... Another record breaking day of heat expected across the region this afternoon as temperatures climb into the upper 80s to mid 90s. A few isolated showers and thunderstorms are possible across the northern Adirondacks and parts of the central and northern Green Mountains today. A very warm and muggy night tonight, will be followed by slightly cooler with more clouds on Thursday. A cold front will produce additional showers and thunderstorms on Friday with some localized heavy rainfall possible. && .NEAR TERM /THROUGH THURSDAY/... As of 639 AM EDT Wednesday...Temps already 2 to 4 degrees warmer this morning compared to yesterday with mainly clear skies prevailing. Any lingering fog/mist will quickly dissipate by 11z, with south winds at 4 to 8 mph expected and highs upper 80s to mid 90s. Still anticipated a few showers/storms to develop over the dacks and parts of the central/northern Greens btwn 18z-23z today. All covered will in fcst. All time record high temp for the month of May maybe broken at BTV this aftn. Our crnt fcst has 94 with the record all time high temp being 93F for BTV. Mid/upper lvl ridge continues acrs the mid Atlantic/NE Conus today with very warm 925mb to 850mb thermal profiles. Progged 925mb temps range from 23-25c today, which adding 10c placed many areas in the upper 80s to mid 90s for high temps. Soundings continue to show as high temps are approached this aftn, mixing of slightly drier air near 850mb transfers to the sfc, resulting in dwpts values in the l/m 60s. This will create heat index values in the 89F to 96F range today, with the warmest values in isolated urban areas acrs the CPV/SLV and parts of the upper CT River Valley. The limited areal coverage of 95 or greater heat index values and limited duration of an hour or two at best, prevents heat advisory thresholds for being reached. Next question is the areal coverage of convection this aftn/evening. Once again mid/upper lvl forcing with building ridge is very weak, along with limited moisture profiles. However, NAM3km and BTV4km, along with the GEM/GFS continue to show some isolated activity building during peak heating this aftn acrs the dacks and parts of the central/northern mtns of VT. Expect llvl convergence from lee side trof on eastern slopes of the dacks and associated lake breezy boundary off both Ontario and Champlain to create enough lift, along with trrn to produce some shower/storm activity this aftn. Deep layer shear is very weak with values <15 knots, so not expecting any organized convective, even with sfc based cape values in the 1800 to 2400 j/kg range. The very light flow <20 knots from sfc thru 500mb, indicates very slow storm motions and the potential for localized heavy down pours. However, areal coverage of measurable precip is <20% in most areas acrs the higher trrn today. A secondary threat would be the potential for an isolated wind gust from localized microburst, associated with efficient preicp loading with moderate cape profiles. Tonight activity will quickly dissipate around sunset as llvl stabilize, with some patchy fog possible in areas that received measurable precip during the daytime. Another very warm and muggy night anticipated with lows upper 50s slk/nek to lower 70s CPV. On Thursday, the combination of clouds and slightly cooler 925mb to 850mb temps will result in high temps in the upper 70s to mid 80s most locations. Several weak embedded 5h vorts move acrs our cwa during the daytime, which could produce scattered showers, with highest pops acrs northern NY/SLV. Progged instability is very limited with sfc based capes <500 j/kg, so thunder threat is minimal on Thurs. Also, soundings indicate near moist adiabatic thermal profiles, indicating the atmospheric stability. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 342 AM EDT Wednesday...Not much change in the overall forecast philosophy for Friday. Warm and muggy with temps in the mid to upper 60s around sunrise warming into the mid to upper 80s. A prefrontal trough will develop during the day with about 800-1500 J/kg of surface based CAPE with continuing trends to a lighter shear profile with 0-6km shear now forecast to be around 35 kts. Due to the relatively weak low-level convergence and lack of a synoptic forcing mechanism, we will need to rely on terrain boundaries and some lake breeze convergence for initiation. But once convection does develop towards late morning/early afternoon, a supportive jet structure, falling heights, and the aforementioned shear should allow for clusters to develop and perhaps organize some capable of producing brief, gusty winds. Starting to see CAM models suggest convective initiation occurs earlier across Central New York, which would place debris clouds over our region in the southwesterly flow. Given this is a common occurrence, this could very likely limit the potential for stronger storms. Moist airmass with 1.6"-1.9" PWATs and a 30-35 kt low-level jet could support training of convection until a stronger upper level vort will push through overnight and allow the strengthening cold front to shift south and east. Decided to include heavy rain wording from about 5 PM to 11 PM. Even with declining instability overnight, thunder chances could continue given the favorable synoptic dynamics. Anticipate roughly 0.25"-0.5" across the region, but there will areas of locally higher amounts associated with any convection, especially if training cells develop. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 342 AM EDT Wednesday...Cold front a little slow to push east as the upper jet becomes more meridionally oriented, and it will come across piecemeal. The Theta- E boundary crosses through about dawn. Not much of a wind shift, still seeing cooler, drier conditions. Highs in the 70s with some upslope showers possible as the secondary front associated with the shift to northwest winds on Saturday evening. This will usher in a cooler air mass with a few days of below normal temps in store with mostly dry conditions forecast. NWP solutions diverge greatly after Monday with regards to a trough digging into the Northern New England and whether it develops into an upper low. If no upper low develops, then a northern stream shortwave trough will propagate through the region on Wednesday. If an upper low does develop, we could end up on the drier side of things as better moisture gets shunted south. Although if the upper low is close enough to the New England coastline, we could get some wrap around precipitation. Not looking at any significant warm up, just a gradual moderate to near normal values for temperatures. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Through 06Z Thursday...Tafs have been challenging this morning with brief ifr at slk/mpv/pbg and mss, but conditions are improving with vfr anticipated through the next 12 to 18 hours. As convective temps are reached, expect cumulus clouds to increase, especially acrs the trrn with some vcsh at slk by 18z. These showers/storms will dissipate by sunset this evening with some patchy fog/br possible again at SLK. However, increasing mid/upper lvl moisture may produce more clouds and limit fog/br and associated ifr/lifr conditions at taf sites tonight. Winds generally south/southwest at 4 to 8 knots, except southeast at PBG associated with lake breezy boundary. Outlook... Thursday: VFR. Slight chance SHRA. Thursday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Friday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance TSRA. Friday Night: Mainly VFR, with local IFR possible. Definite SHRA, Chance TSRA. Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA. Saturday Night: VFR. Slight chance SHRA. Sunday: VFR. NO SIG WX. && .CLIMATE... High temperatures in the upper 80s to mid 90s are forecast today. Here is a look at the daily record high temperatures for May 27th, along with the all time monthly record high temperatures for May. The all time monthly high temperatures include: 93 at BTV, 90 at MPV, 91 at 1V4 ASOS and 96 at COOP, 96 at MSS, 94 at PBG, and 94 at SLK. Date KBTV KMPV K1V4 KMSS KPBG KSLK 05-27 91|2016 88|1960 86|2016 89|2016 94|2016 88|1914 && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && SYNOPSIS...Taber NEAR TERM...Taber SHORT TERM...Haynes LONG TERM...Haynes AVIATION...Taber CLIMATE...Banacos/Taber/Haynes
Hazardous Weather Outlook National Weather Service Burlington VT 302 AM EDT Wed May 27 2020 NYZ026>031-034-035-087-VTZ001>012-016>019-280715- 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-Windsor- Eastern Franklin-Eastern Chittenden-Eastern Addison-Eastern Rutland- 302 AM EDT Wed May 27 2020 This Hazardous Weather Outlook is for northern New York, central Vermont, northeast Vermont, northwest Vermont and southern Vermont. .DAY ONE...Today and tonight. Very warm temperatures are expected this afternoon with highs in the upper 80s to lower 90s. Localized heat index values will be near 95 across the urban areas of the Champlain and Saint Lawrence Valleys. Isolated to scattered showers and thunderstorms are expected across the northern Adirondacks and parts of the central and northern mountains in Vermont this afternoon. Any storm that develops will be capable of localized heavy rainfall, brief gusty winds, and frequent lightning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Additional showers and thunderstorms are likely on Friday into Friday night across the North Country. These storms will have the potential to produce localized very heavy rainfall in a short period of time and isolated gusty winds. The threat for flooding is minimal at this time, given the recent dry spell. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Burlington radar (KCXX), 9 km away, was scanning. The volume nearest the first event began at 17:09 UTC.
3 thunderstorm wind, 1 heat. Local standard time, as filed.
Record Heat with Daily High records broken at Burlington, Montpelier, St. Johnsbury and Mount Mansfield. Burlington broke the warmest May temperature ever with 95 degrees.|Mount Mansfield set an ALL-TIME Record with 85 degrees.
Reports of multiple trees and power lines down near Route 107 and Abbot road.
Trees down along Route 12A in Roxbury.
Trees and power lines down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Vermont in 2020Every state in 2020This day in weather historyWarnings in Vermont, May 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: 883162, 883159, 883160, 883161.