Record setting heat set the stage for an moderately unstable air mass, while a mid-level atmospheric disturbance provided the forcing and strong winds to develop scattered thunderstorms by late afternoon into early evening, some of which produced damaging winds and hail. A strong micro-burst produced 80-100 mph winds and destructive hail in West Addison with a seasonal camp destroyed with one…
Every event with a place to put it. 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 setting heat set the stage for an moderately unstable air mass, while a mid-level atmospheric disturbance provided the forcing and strong winds to develop scattered thunderstorms by late afternoon into early evening, some of which produced damaging winds and hail.
A strong micro-burst produced 80-100 mph winds and destructive hail in West Addison with a seasonal camp destroyed with one occupant receiving minor injuries. More than 15,000 customers were without power due to storms across VT.
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 18, 2:55 PM EST, 1 hour 30 minutes earlier.
Area Forecast Discussion National Weather Service Burlington VT 355 PM EDT Thu May 18 2017 .SYNOPSIS... After another day of record heat, isolated strong to severe thunderstorms are expected through this evening...with the primary threat being gusty winds and hail. Much cooler and drier weather arrives by midday Friday with some patchy frost possible by Saturday morning. A warm front will produce scattered showers on Sunday afternoon with temperatures returning to near normal. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 350 PM EDT Thursday... Severe thunderstorm watch number 237 in effect for entire cwa until 03z this evening. Vis sat shows vertical cumulus development occurring across the western dacks with radar just showing the first signs of convective development near Tupper Lake. Expect coverage to increase this aftn/evening as better dynamics arrive and the cap lifts. Wind advisory continues until 03z with kmss gusting to 44 mph last hour. Forecast concern this evening will be areal coverage and magnitude of convection...followed by temps. Expecting isolated strong to locally severe storms to fire late this aftn along pre-frontal trof and associated weak embedded 5h vort in the flow aloft. The pre- storm environment this aftn/evening shows CAPE values between 1500 to 2000 j/kg with a ribbon of enhanced 0 to 3 km/0 to 6 km shear values between 40 and 50 knots. This instability/shear supports isolated/scattered cluster of storms with some individual bowing line segments. The 1st round looks to impact mainly the eastern Dacks...southern/central CPV...and parts of central/southern and eastern VT between 20-00z this evening. Expecting a few strong to severe storms in this time period. Meanwhile...another broken line of showers/storms will be approaching the SLV by 00z this evening. Still some uncertainty with regards to amount of instability with cool lake water impacting environment...along with impacts of upstream convection stabilizing atmosphere. If environment can recover enough btwn 00z-03z...expecting a broken line of strong storms with some enhanced wind threat associated with very strong 925mb to 850mb winds of 45 to 55 knots. These storms will weaken as they enter the CPV around midnight tonight. A very mild start to the evening expected with temps mainly in the 70s to near 80f in areas away from convection...but as strong cold front swings across our region after midnight...expect temps to quickly fall. By morning...expecting temps to range from the upper 40s slv/western dacks to lower 60s near VSF. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... As of 350 PM EDT Thursday...sharp cold front is draped across southern New England at 18z Friday with moderate low level caa continuing across our cwa. Progged 850mb temps range between 10-12c around 12z...but fall between 2-4c by 18z Friday...supporting nearly steady temps or falling during the morning hours. Thinking clouds break up during the afternoon hours and temps warm back into the mid 50s to lower 60s most locations...but with breezy northwest will make for a chilly mid May day. Some lingering mainly terrain drive rain showers are possible from 12z to 16z...but rapid drying aloft...will quickly dissipate showers by Friday afternoon. Friday Night thru Saturday Night...1030mb high pres builds into the region during this time period with dry conditions and cool temps. Based on clear skies and winds decoupling in deeper protected valleys...expect some patchy frost to develop. Best chances for frost will be dacks and valleys of central/northern VT...including the NEK. Will mention lows ranging from the mid/upper 20s NEK/SLK to near 40F CPV/SLV. A nice day is expected on Saturday with plenty of sunshine and slightly below normal temps. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 317 PM EDT Thursday...Upper level ridge and exiting surface high pressure off the Atlantic seaboard will keep dry conditions across the North Country to end the weekend with increasing clouds ahead of our next system encroaching from the west during the afternoon. Deep low pressure over southern Ontario tracks eastward into central Quebec Sunday night through Monday dragging a cold front through northern New York and Vermont with showers developing late Sunday evening across western areas and becoming widespread after midnight through Monday as a weak wave of low pressure forms over the mid- Atlantic states and rides northeast to the Gulf of Maine by Monday night. In contrast to the previous forecast, the 12z model suite indicates very little instability both at the surface and aloft to support thunder so I've removed all mention. Is a rumble or tow of thunder possible, sure. Just not enough to justify it in the forecast. Brief break in precipitation occurs Tuesday as we'll be in between systems, with the next chance for showers and potential thunderstorms coming Wednesday/Wednesday night as deepening low pressure over Great Lakes Tuesday night tracks northeast through the St. Lawrence Valley. Temps through the period will be very seasonal with highs in the mid 60s to low 70s, and lows in the mid 40s to low 50s. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... Through 18Z Friday...Primarily VFR conditions are expected through 12Z Friday with 2 rounds of scattered showers and thunderstorms this afternoon and evening briefly reducing vsby/cigs to MVFR/IFR. After 12Z, there will be a gradual trend towards MVFR as cigs lower behind a cold front passage. For winds, gusty to locally strong south-southwest with gusts in the 20-35kt range persist through about midnight before shifting to the west-northwest at 8-15kts. Outlook... Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Slight Chance SHRA...TSRA. Sunday Night: VFR. Likely SHRA...TSRA. Monday: MVFR. Likely SHRA...TSRA. Monday Night: VFR. Slight Chance SHRA. Tuesday: VFR. Slight Chance SHRA. && .CLIMATE... Max Temp Records for 5/18/17 KBTV...89 set in 1989 KMPV...90 set in 1962 K1V4...92 set in 1906 KMSS...90 set in 1962 && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...Wind Advisory until 11 PM EDT this evening for NYZ026-027-087. && SYNOPSIS...Taber NEAR TERM...Taber SHORT TERM...Taber LONG TERM...Lahiff AVIATION...Lahiff CLIMATE...WFO BTV
Hazardous Weather Outlook National Weather Service Burlington VT 354 AM EDT Thu May 18 2017 NYZ026-027-087-190800- Northern St. Lawrence-Northern Franklin-Southwestern St. Lawrence- 354 AM EDT Thu May 18 2017 ...WIND ADVISORY IN EFFECT FROM 2 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING... This Hazardous Weather Outlook is for northern New York. .DAY ONE...Today and Tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Wind Advisory. .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. NYZ028>031-034-035-VTZ001>012-016>019-190800- Eastern Clinton-Southeastern St. Lawrence-Southern Franklin- Western Clinton-Western Essex-Eastern Essex-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- 354 AM EDT Thu May 18 2017 This Hazardous Weather Outlook is for northern New York, central Vermont, northeast Vermont, northwest Vermont and southern Vermont. .DAY ONE...Today and Tonight. Scattered showers and thunderstorms are expected to develop late this afternoon and continue into the evening hours. A few of these storms may become strong to severe with hail and strong winds as the primary threat. .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.
SPECIAL WEATHER STATEMENT National Weather Service BURLINGTON VT 1228 PM EDT Thu May 18 2017 NYZ026>031-034-035-087-VTZ001>012-016>019-182000- 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- Including the cities of Massena, Malone, Plattsburgh, Star Lake, Saranac Lake, Tupper Lake, Dannemora, Lake Placid, Port Henry, Ticonderoga, Ogdensburg, Potsdam, Gouverneur, Alburgh, South Hero, St. Albans, Newport, Island Pond, Burlington, Johnson, Stowe, St. Johnsbury, Montpelier, Middlebury, Vergennes, Bradford, Randolph, Rutland, Springfield, White River Junction, Enosburg Falls, Richford, Underhill, Bristol, Ripton, East Wallingford, and Killington 1228 PM EDT Thu May 18 2017 ...Isolated Strong to Severe Thunderstorms Expected Late This Afternoon into the Evening Hours... Thunderstorms are expected to developing over the high peaks of the Adirondack Mountains between 3 PM and 5 PM today and move into central, southern, and eastern Vermont during the late afternoon. A couple of severe thunderstorms are possible with the primary threat being localized damaging wind gusts and isolated one inch hail. Meanwhile, a broken line of showers and thunderstorms will approach the Saint Lawrence Valley by 8 PM this evening. These storms will be capable of producing localized strong wind gusts. Please stay tuned to NOAA Weather Radio, your local media, or go to www.weather.gov/Burlington for further updates on this weather situation.
Special Weather Statement National Weather Service Burlington VT 411 PM EDT THU MAY 18 2017 NYZ030-031-034-182045- Southern Franklin-Western Essex-Western Clinton- 411 PM EDT THU MAY 18 2017 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN CLINTON... SOUTHEASTERN FRANKLIN AND NORTHWESTERN ESSEX COUNTIES... At 411 PM EDT, a strong thunderstorm was located near Wawbeek, moving east at 50 mph. Locations impacted include... Saranac Lake, Adirondack Regional Airport, Wilmington, Wawbeek, Harrietstown, Hawkeye, Paul Smiths, Union Falls, Saranac Inn, Ray Brook, Lake Colby, Riverview, Rainbow Lake, Loon Lake, Gabriels, Lake Clear, Upper Saint Regis, Onchiota, St. Regis Mountain and Vermontville. LAT...LON 4423 7434 4439 7444 4464 7393 4435 7372 TIME...MOT...LOC 2011Z 249DEG 44KT 4432 7436 RDEAL
Special Weather Statement National Weather Service Burlington VT 443 PM EDT THU MAY 18 2017 NYZ028-031-034-035-VTZ001-005-182115- Eastern Clinton-Western Essex-Eastern Essex-Western Clinton-Grand Isle-Western Chittenden- 443 PM EDT THU MAY 18 2017 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN CLINTON... NORTHEASTERN ESSEX...SOUTHWESTERN GRAND ISLE AND WEST CENTRAL CHITTENDEN COUNTIES... At 442 PM EDT, a strong thunderstorm was located over Wilmington, moving east at 45 mph. Winds in excess of 30 mph and half inch hail are possible with this storm. Locations impacted include... South Burlington, Essex, Peru, Willsboro, Wilmington, Charlotte, Port Kent, Au Sable Forks, Keeseville, Jay In Essex County, Shelburne, South Hero, Colchester, Black Brook, Sloop Island, Wings Point, Stave Island, Sunset Island, Meach Island and Hatch Point. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. Boaters on Lake Champlain should seek safe harbor now! Strong winds will cause higher waves and sudden wind shifts may overturn boats. A severe thunderstorm watch remains in effect until 1100 PM EDT for northern New York...and northwestern Vermont. LAT...LON 4430 7381 4449 7388 4465 7333 4430 7322 TIME...MOT...LOC 2042Z 258DEG 41KT 4442 7378 RDEAL
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
503 PM EDT THU MAY 18 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM HAIL 1 E NASHVILLE 44.45N 72.93W
05/18/2017 M0.25 INCH CHITTENDEN VT NWS EMPLOYEE
&&
EVENT NUMBER BTV1701904
TABERSpecial Weather Statement
National Weather Service Burlington VT
503 PM EDT THU MAY 18 2017
VTZ003-006>008-017-182200-
Caledonia-Eastern Chittenden-Washington-Orleans-Lamoille-
503 PM EDT THU MAY 18 2017
...A STRONG THUNDERSTORM WILL AFFECT LAMOILLE...CALEDONIA...SOUTHERN
ORLEANS...EAST CENTRAL CHITTENDEN AND NORTHERN WASHINGTON COUNTIES...
At 502 PM EDT, a strong thunderstorm was located over Morrisville,
moving east at 40 mph.
Winds in excess of 40 mph and pea size hail are possible with this
storm.
Locations impacted include...
St. Johnsbury, Lyndon, Morrisville, Johnson Village, Calais, Glover,
Waterbury Village, Hyde Park, Greensboro Bend, Worcester, Middlesex,
Marshfield, Cabot Village, West Burke Village, Morrisville Village,
Woodbury, Cabot, Willoughby, Underhill State Park and Elmore.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
LAT...LON 4476 7192 4432 7203 4426 7206 4436 7303
4438 7305 4461 7287 4478 7196
TIME...MOT...LOC 2102Z 259DEG 36KT 4458 7261PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
505 PM EDT THU MAY 18 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 PM HAIL MORRISVILLE 44.56N 72.60W
05/18/2017 M0.25 INCH LAMOILLE VT PUBLIC
&&
EVENT NUMBER BTV1701905
TABERThe Burlington radar (KCXX), 4 km away, was scanning. The volume nearest the first event began at 21:25 UTC.
12 thunderstorm wind, 7 hail. Local standard time, as filed.
A measured wind gust of 50 knots was recorded at Burlington Int'l Airport along with scattered large branches of softwoods (pines) falling on property causing some damage.
Dime to nickel size hail observed for two minutes along with strong gusty winds near 50 mph that knocked down several limbs of a Willow tree.
Strong thunderstorm winds estimated to be 50 knots or greater occurred across portions of Williston, especially north of Route 2A. Several reports of large tree branches of softwoods (pines/willows) downed by thunderstorm winds, causing power outages and minor structural damage.
Tractor trailer blown over on Interstate 91 as well as trees blocking railroad tracks.
Strong thunderstorm winds downed large tree branches onto power lines in eastern Williston.
Strong thunderstorm winds downed several large tree branches and a few soft wood trees (pines) on Sandhill road and nearby neighborhoods in Essex, causing power outages.
Trees and power lines down by thunderstorm winds.
Trees and power lines down by thunderstorm winds.
Trees and power lines down by thunderstorm winds.
A destructive hail storm and destructive thunderstorm winds caused considerable damage along Potash Bay road and Lake street. Hail stones of 1 to 1.5 inches in diameter blown by 60-80 mph winds produced numerous holes in siding, dents on vehicles and broken windows in the most severe occurrence on Lake street. Hail damage as witnessed in this survey is highly unusual in Vermont and northern NY.
NWS survey team determined a microburst with winds estimated between 80-100 mph initiated across Lake Champlain and moved ashore on Potash Bay road with the maximum extent of damage occurring on Potash Bay road and Lake street. A summer camp was partial lifted from it's foundation and rolled onto it's side with neighboring homes witnessing some structural damage in terms of missing/damaged gutters and shutters. Dozens to hundreds of Willow and Pine trees were snapped or uprooted and damaging hail accompanied these winds.
A 75 year old female was in the camp at the time of the storm and received minor injuries.
Other, more scattered wind damage from this storm was along the lake shore in a 2-3 mile radius as well as east to Route 22A.
Trees and power lines down by thunderstorm winds.
Quarter-size hail reported along with strong gusty winds.
Dime size hail reported.
Hail occurring for several minutes with sizes up to dime size or slightly larger accumulating an inch or more in portions of the area.
Dime size hail reported.
Dime size hail reported.
Huge trees downed by thunderstorm winds.
Measured wind gust of 59 knots as well as some tree damage.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Vermont in 2017Every state in 2017This day in weather historyWarnings in Vermont, May 2017
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: 687528, 687514, 687527, 687566, 687529, 687530, 687564, 687569, 687571, 687520, 687537, 687572, 687515, 687521, 687523, 687524, 687525, 687574, 687575.