Saturday August 17, 2019
Severe Thunderstorm Event
Schenectady/Southern Saratoga County Torrential Supercell - Evening Squall Line

Shelf cloud advancing on Mohawk Harbor in Schenectady - Late afternoon Saturday August 17, 2019
Photo Credit: Steve LaPointe

Troy Skycam looking toward Albany as the Severe T'Storm was moving into the city around 5:46pm August 16, 2019 

For a second day in a row, severe weather developed across eastern New York and western New England with downpours and thunderstorms becoming widespread during the late afternoon and evening in what was a hot, humid, and unstable air mass with temperatures well into the mid and upper 80s and dewpoints ranging from 65°-70°. CAPE, or convective available potential energy, was running high, in the 1500 j/kg to 2500 j/kg range with moderate wind shear, especially aloft with strong southwest flow in the mid levels. The surface flow was weak, however, but was backed in the Hudson valley into a SSE direction which did enhance directional shear, favorable for rotating updrafts with any isolated cellular thunderstorms in the high instability environment.

And two such isolated and intense storms did form in what was a weakly capped atmosphere, during the early to mid afternoon. The first storm fired over southeast Schenectady County around 1:45 pm and the other a short time later near Galway in Saratoga County. Both of these storms became supercells with rotating updrafts with the Schenectady County storm producing significant wind damage and hail, as well as frequent vivid lightning, and flooding rainfall in Schenectady, Niskayuna and Clifton Park between 2:30pm and 4pm. In just a couple of hours, 2.57" of rain fell in the southern Clifton Park/Rexford area due to the slow moving nature of that storm. Trees and power lines were blown down in Niskayuna with power outages reported there. The radar image below shows the two isolated slow moving supercells, with severe thunderstorms warnings on them, at 2:45pm.

Radar and Warnings, 2:45pm Saturday August 17, 2019 

The approach of a weak upper level disturbance and the associated lift in the atmosphere it generated then triggered a line of downpours and locally strong and severe thunderstorms to develop and move from west to east across the region from the late afternoon through the evening, feeding on the hot, humid, and unstable air mass that was in place. A few of the stronger storms within the line produced localized severe wind gusts with spotty tree and power line damage in Schoharie, Schenectady, Albany, Saratoga, and Washington counties between 4:45pm and 6pm. The southern part of the line was less intense but still went on to produce considerable lightning and torrential rainfall when it moved through the Catskills, mid Hudson valley, and Berkshires through 9pm. The Instant Doppler 6 images below illustrate the scope and coverage of the line as it moved through the region.

Instant Doppler 6 base reflectivity image at 4;15pm Saturday August 17, 2019 - The image shows a squall line of downpours and strong thunderstorms stretching from Warren County south into the Mohawk valley and western Catskills. The two lead supercells had dissipated by this time.

Instant Doppler 6 Image at 4:15pm Saturday August 17, 2019 

Instant Doppler 6 base reflectivity image at 5:00 pm Saturday August 17, 2019

 Instant Doppler 6 Image at 5:00pm Saturday August 17, 2019

Instant Doppler 6 base reflectivity image at 6:15 pm Saturday August 17, 2019

Instant Doppler 6 Image at 6:15pm Saturday August 17, 2019 

NWS Storm Reports for Saturday August 17, 2019. Note, these reports are used to verify the NWS warnings which were issued for this event and therefore do not necessarily represent an accounting for all of the wind damage which may have occurred.

Town County Severe Weather Report Time
Schenectady Schenectady Flash Flood: Rapid flooding reported at the intersection of Parkwood Blvd. and Rugby Road 2:50pm
Galway Saratoga Wind Damage: Trees and power lines blown down 2:53pm
Schenectady Schenectady Wind Damage: Several Large tree limbs down on West Alley 2:55pm
Niskayuna Schenectady Wind Damage: Tree blown down near Niskayuna High School 2:55pm
Schenectady Schenectady Flash Flood: Street flooding reported in many sections of Schenectady 3:00pm
Schenectady Schenectady Hail: Measured 1.00" Diameter Hail 3:00pm
Hawthorne Hill Schenectady Torrential Rain: 2.60" of rain 3:25pm
Poland Herkimer Flash Flood: Flooding reported in Poland and Newport with up to 2.5' of water on some roadways 4:00pm
Cobleskill Schoharie Wind Damage: Trees and wires blown down 4:55pm
Schoharie Schoharie Wind Damage: Tree blown down on wires 5:02pm
2 Miles NNE of Esperance Schenectady Wind Damage: Wires down on Eaton Corners Road 5:07pm
3 Miles N. of Esperance Schenectady Tree and wires blown down 5:09pm
Rotterdam Schenectady Wind Damage: Tree limb on wires 5:15pm
Knox Albany Wind Damage: Tree blown down 5:15pm
Corinth Saratoga Wind Damage: Tree and power lines blown down onto a roadway 5:19pm
Niskayuna Schenectady Wind Damage: Multiple trees snapped and blocking Ardsley Road 5:19pm
Ballston Lake Saratoga Wind Damage: Several trees blown down 5:20pm
Galway Saratoga Wind Damage: Tree and lines down 5:20pm
Corinth Saratoga Wind Damage: Lines blown down 5:20pm
3 Miles WNW of Berne Schoharie Wind Damage: Tree and wires blown down 5:20pm
Gansevoort Saratoga Wind Damage: Several large trees blown down onto a roadway 5:24pm
Malta Saratoga Wind Damage: A few trees blown down 5:25pm
Clifton Park Saratoga Wind Damage: A few trees blown down in the northern parts of Clifton Park 5:25pm
Saratoga Springs Saratoga Wind Damage: Numerous reports of trees and wires down in and around Saratoga Springs 5:30pm
Stillwater Saratoga Wind Damage: A few trees blown down 5:30pm
Esperance Schoharie Wind Damage: Wires blown down 5:37pm
Granville Washington Wind Damage: Limbs down on wires 6:00pm
Kingsbury Washington Wind Damage: Limbs down on wires in Kingsbury 6:09pm

 

Storm Reports For Saturday August 17, 2019

Storm Prediction Center Storm Reports For August 17, 2019