A strong cold front and upper level system approached northern NY during the afternoon of August 22nd and moved through during the night. Numerous thunderstorms moved across northern NY during the afternoon with several producing damaging winds in the form of downed trees and power lines.
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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 strong cold front and upper level system approached northern NY during the afternoon of August 22nd and moved through during the night. Numerous thunderstorms moved across northern NY during the afternoon with several producing damaging winds in the form of downed trees and power lines.
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 Aug 22, 11:48 AM EST, 1 hour 4 minutes earlier.
Area Forecast Discussion National Weather Service Burlington VT 1248 PM EDT Tue Aug 22 2017 .SYNOPSIS... Quiet weather will come to an end with thunderstorms firing today ahead of an approaching cold front. Some storms may have damaging winds and very heavy rain. Cold front moves across the area overnight an storms come to an end. The remainder of the week is shaping up to be cooler and drier with below normal temperatures. && .NEAR TERM /THROUGH WEDNESDAY/... As of 1245 PM EDT Tuesday...Well, big day. Tornado watch has been issued from the Champlain Valley wwd across northern NY through 9pm this evening. On track for a relatively widespread SVR event with strong deep-layer wind fields, moderate instability (CAPE 1500-2500 J/kg), and increasing synoptic forcing from the west lining up well with peak daytime/boundary layer heating. Also seeing low 70s PBL dewpoints streaming nwd from swrn New England and the lower Hudson Valley, which will contribute to moderate CAPE and PW values increasing to near 2". Mid-level lapse rates aren't particularly steep, but shouldn't be much of a mitigating factor given strong mid-level forcing/UVV. Should see one or more bands of thunderstorms moving into nrn NY by 18-19Z, with embedded bow echoes producing damaging winds as the primary threat. Given strong low-level helicity, may see QLCS type (brief) tornadoes within the line from the Champlain Valley wwd, which has warranted the tornado watch. Torrential rain is also possible, but activity should be forward propagating and not expecting training cells that would pose a hydro threat. Will need to watch for a few supercells in advance of the line given strength of low-level and deep-layer shear, with an isolated tornado possible. Activity should reach the Champlain Valley around 20-21Z and clear east of VT by 23-00Z. Previous Discussion...Today will be a very active weather day with severe thunderstorms possible this afternoon. Thunderstorms will develop ahead of approaching cold front, crossing our forecast area from West to East. The main window will be from noon to 6 pm. SPC has placed part of our area in an enhanced risk with slight everywhere else. A low pressure system will deepen as it tracks from the Northern Great Lakes, northeastward towards Quebec. A strong upper level trough will also approach from the west during this timeframe. Strong southwesterly flow will be increasing today and advecting deep low level moisture into the region. Pwats will be over 2" in some spots. Cape will be around 800-2000 J/k. Increasing shear profiles are also expected ahead of the approaching cold front, will have a 500 mb jet around 50 kts overhead, this brings 0-6 km bulk shear of about 40 kts. These ingredients all add up to some strong to severe storms developing. The main risk with these storms will be damaging winds, perhaps in the form of a bow echo. Pwats up around 2" will make heavy rain an expectation, but storms should be moving along fast enough to avoid any big flash flood problems. Temperatures will once again reach the mid to upper 80s today. Cold front moves across the area overnight and thunderstorms will be dying down as the night wears on. May see some showers with the surface frontal passage, but severe threat will be diminished. A few additional showers are possible Wednesday as upper level trough finally makes its way across our area. Temps on Wed will be about 10 degrees cooler than Tue, much closer to seasonal normals. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... As of 426 AM EDT Tuesday...500mb cyclonic flow continues to influence the North Country Wednesday night through Friday. Multiple vorts look to move across the region throughout the short term, keeping some clouds and possible showers in the forecast. Generally under southwest flow aloft and 500mb height falls support some showery activity, probably with the help of orographic lift as a building ridge at the surface results in north to NW flow in the lower levels. Decreasing PWATs will limit available moisture, hence only slight to low chance PoPs at this point. Temperatures throughout the period will be slightly cooler than normal. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... As of 426 AM EDT Tuesday...Pattern in the short term continues with 500mb trough swinging through the region over the weekend with some vort maxes rotating about the trough. High pressure remains at the surface, keeping precip light. Some ridging aloft may begin to develop during the start of the work week. This would lead to dry conditions as the 500mb trough slides eastward. Temperatures continue to be about 5 degrees cooler than normal. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... Through 12Z Wednesday...Areas of patchy fog will erode this morning, with VFR conditions persisting through early afternoon /mid-day. Southerly winds quickly increase between 12-15z with localized gusts to 25 kts. Lake breeze boundary will keep winds at 150 to 170 at PBG until midday. Strong to severe thunderstorms will develop between 16z-01z with possible localized strong/gusty winds, creating areas of moderate/severe turbulence and wind shear, along with frequent lightning. Also expect periods of heavy downpours to deteriorate flight conditions to MVFR/IFR when directly affecting terminals. Some storms will develop in warm moist airmass and more organized storms will develop along a frontal boundary that will move from west to east across the North Country. Expect storms to be most prevalent around KMSS/KSLK around 18Z-22Z, reaching the Champlain Valley around 20-00Z, then exiting southeast VT after 01Z. Some lingering showers possible heading into Tuesday night. While gusts are expected to subside, sustained winds of 8-15kts are expected to continue overnight. Outlook... Wednesday: VFR. Breezy. Slight Chance SHRA. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. Slight Chance SHRA. Thursday Night: VFR. NO SIG WX. Friday: VFR. Slight Chance SHRA. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. && .MARINE... A Lake Wind Advisory has been issued for the remainder of the day across Lake Champlain. South winds will increase to 20-25kts late this morning and continue thru this afternoon with increasing pressure gradient and channeled flow in the Champlain Valley. Waves will build to 2-3ft, highest across the northern end of the broad lake. A line of thunderstorms will likely affect Lake Champlain late in the afternoon with potential for damaging winds. Boaters should stay alert, listen for possible warnings, and return to port when threatening weather approaches. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && SYNOPSIS...Neiles NEAR TERM...Banacos/Neiles SHORT TERM...KGM LONG TERM...KGM AVIATION...KGM MARINE...Banacos
Hazardous Weather Outlook National Weather Service Burlington VT 435 AM EDT Tue Aug 22 2017 NYZ026>031-034-035-087-VTZ001>012-016>019-230845- 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- 435 AM EDT Tue Aug 22 2017 This Hazardous Weather Outlook is for northern New York, central Vermont, northeast Vermont, northwest Vermont and southern Vermont. .DAY ONE...Today and Tonight. Severe thunderstorms are expected this afternoon and evening. The primary threat will be localized damaging winds capable of knocking down trees and power lines. Thunderstorms are expected to develop over Northern New York around noon and track eastward into Vermont during the late afternoon and early evening. Brief heavy rainfall and frequent lightning is expected with thunderstorm activity. .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
116 PM EDT TUE AUG 22 2017
NYZ026-027-029-030-087-221815-
Northern St. Lawrence-Northern Franklin-Southeastern St.
Lawrence-Southern Franklin-Southwestern St. Lawrence-
116 PM EDT TUE AUG 22 2017
...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN FRANKLIN
AND ST. LAWRENCE COUNTIES...
At 116 PM EDT, radar indicated strong thunderstorms were located
along a line extending from 11 miles northwest of Ogdensburg to near
Morristown to 6 miles southeast of Hammond. Movement was northeast at
50 mph.
Winds in excess of 40 mph are possible with these storms.
Locations impacted include...
Potsdam, Massena, Gouverneur, Canton, Ogdensburg, Norfolk, Lisbon,
Louisville, Moira, De Kalb, Fowler, Parishville, Colton, Bombay,
Morley, Degrasse, Massena International Airport - Richards Field,
Helena, Carry Falls Reservoir and Waddington.
These storms will 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 4500 7453 4493 7448 4440 7452 4414 7528
4431 7566 4443 7580 4445 7576 4445 7578
4451 7575 4488 7522 4496 7492 4497 7496
4498 7494 4499 7489 4498 7492 4497 7493
4497 7488 4500 7489 4501 7483
TIME...MOT...LOC 1716Z 246DEG 42KT 4480 7568 4462 7554 4436 7564The Ft Drum radar (KTYX), 96 km away, was scanning. The volume nearest the first event began at 17:51 UTC.
5 thunderstorm wind. Local standard time, as filed.
Several trees downed by thunderstorm winds.
Tree and branches down across road due to thunderstorm winds.
Several trees downed by thunderstorm winds.
Several trees downed by thunderstorm winds.
Several power lines downed by thunderstorm winds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New York in 2017Every state in 2017This day in weather historyWarnings in New York, August 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: 711117, 711119, 711118, 711120, 711121.