Wednesday June 30, 2021
Severe T'Storm Event

Widespread fast moving multi-cell clusters of thunderstorms erupted in a hot and oppressively humid atmosphere on this day from the early to mid afternoon through the early evening hours well in advance of a slow moving cold front approaching western New York. There were 51 reports of severe weather in the WRGB coverage area with most being straight line downburst winds with a few instances of hail up to 1" in diameter.

The most concentrated zone where wind damage occurred stretched along a path from Syracuse to Utica through southern Herkimer, Fulton, central Saratoga, southern Washington and southern Bennington counties between 1:30 and 3:30pm where an organized multi-cell severe thunderstorm produced pockets of wind damage as well as frequent lightning, hail and torrential rainfall.

Another severe multi-cell t'storm produced 75-85 mph microbursts along an almost four mile path from Canaan in Columbia County to Richmond, MA in Berkshire County between 3:40 and 3:50pm according to a National Weather Service damage survey. The Albany NWS also surveyed damage in Wappingers Falls in Dutchess County and discovered a 75-85 mph microburst produced tree damage along a 1.5 mile path in a couple of pockets between 6:52 and 6:54pm.

The storm reports graphic below highlights the long track severe multi-cell across the local area as well as the other pockets of wind damage that occurred from other storms.


Local Storm Reports - June 30, 2021

Storm motion was swift to the east at speeds of 40-45 mph with that fast motion limiting rainfall amounts in most areas and limiting much flooding potential. However, repeat torrential thunderstorms in a narrow corridor across south central Berkshire County produced, by radar estimates, over 4.00" of rainfall in a short period of time which did result in some brief flash flooding in Lenoxdale and Becket during the early evening with an estimated six to eight inches of water covering Route 8 near Washington town park in Becket around 7:00pm. The zone of heaviest rainfall, however, was narrow, as our WeatherNet 6 spotter in Becket, just south of the deluge, reported only 0.75" of rain.

The image below shows the narrow zone of where the heaviest rainfall in Berkshire County fell on June 30 during the late afternoon and early evening. The area shaded in purple just to the north of Becket highlights where radar had estimated 4.0"+ rainfall with anywhere from 2.0" to 3.0" in the blue shaded zone, which extended into Columbia County.

Radar rainfall estimate graphic - Berkshire County - June 30, 2021 

SET-UP
The atmosphere was characterized by a sunny morning with hot and oppressively humid conditions in place in the final day of a four day heat wave. Daytime maximum temperatures soared into the upper 80s to low 90s with some mid 90s in the mid Hudson valley with dewpoints ranging from the upper 60s to the lower 70s. Aloft, a moderately strong belt of westerly flow with 30-50 knots of generally unidirectional shear was in place which was more than sufficient to promote storm organization. Further, the region was located in a favorable quadrant of an upper level jet stream feature which promoted some extra large scale atmospheric lift over the Northeast, a favorable ingredient for thunderstorm development.

Surface basead CAPE values (convective available potential energy) increased to between 2500 and 3000 j/kg from the Mohawk valley south into the Catskills, Capital Region to Bennington County, VT, and possibly up to 3500 j/kg, per the Storm Prediction Center objective analysis, in the mid Hudson valley and Berkshires, indicating high amounts of instability across the region favoring robust tall convective updrafts capable of bringing down strong winds from aloft. Steep low level lapse rates due to the strong heating of the day were in place which favored rapidly rising air in the lower levels and good atmospheric mixing.

Mitigating factors in this event included modest mid level lapse rates, which would serve to decrease buoyancy aloft and slow updraft speeds as well as a lack of a decent low level front or trough to act as a convergence boundary with a largely west to northwest surface flow across eastern New York and western New England. (This severe weather event would have been more potent had these parameters lined up in a more favorable way.)

THE EVENT
Thunderstorms initially developed along what was likely a lake breeze or wind shift boundary over west central New York and along some differential heating boundaries in the Adirondacks with upscale development and growth fairly rapid due to the high levels of instability or fuel which the thunderstorms readily consumed. The fast flow aloft favored multi-cell development and a fast forward storm speed. A few very brief transient supercell structures developed and in those cases brief hail cores were able to develop with a few reports of hail up to 1" in diameter with the storm that impacted Utica, southern Herkimer and western Fulton counties.

With a lack of any strong convergence boundaries to focus storms, smaller outflow boundaries generated by thunderstorms acted as the focal areas for additional thunderstorm development and the propagation of the event south and east through the region.

The initial severe multi-cell storm that moved along that path just north of the Mohawk river to southern Bennington County, VT during the early to mid afternoon put out an outflow boundary that caused additional short lines and clusters of storms to form in the western Catskills to Schoharie County and the Capital Region with those storms subsequently putting out outflow boundaries of rain cooled air, or a mini cold fronts, that went on to initiate the final cluster of storms over the eastern Catskills, mid Hudson valley to southern Berkshire and Litchfield counties very late in the afternoon and early in the evening with the action ultimately shifting east into Connecticut through the evening marking an end to the event locally around 7:30pm.

The following series of Albany Doppler weather radar images chronicles the progress of the initial long track multi-cell storm cluster that moved east across the region north of the Mohawk river into Bennington County, VT between 1:30 and 3:30pm

Albany Doppler Radar Base Reflectivity Image - 1:29pm June 30, 2021

Albany Doppler Radar Image: 1:30pm June 30, 2021

Albany Doppler Radar Base Reflectivity Image - 2:00pm June 30, 2021

Albany Doppler Radar Image: 2:00pm June 30, 2021

Albany Doppler Radar Base Reflectivity Image - 2:30pm June 30, 2021

Albany Doppler Radar Image: 2:30pm June 30, 2021

 Albany Doppler Radar Base Reflectivity Image - 3:00pm June 30, 2021

 Albany Doppler Radar Image: 3:00pm June 30, 2021

  Albany Doppler Radar Base Reflectivity Image - 3:30pm June 30, 2021

Albany Doppler Radar Image: 3:30pm June 30, 2021

NWS Storm Reports for Wednesday June 30, 2021. 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
Frankfort Herkimer Wind Damage: Trees and wires blown down 1:34pm
Ilion Herkimer Wind Damage: Trees and wires blown down 1:37pm
Herkimer Herkimer Wind Damage: Trees and wires blown down 1:41pm
Johnstown Fulton Wind Damage: Trees and wires blown down 2:16pm
Gloversville Fulton Wind Damage: Tree blown down on a house near the intersection of 5th Avenue and Helwig Street 2:18pm
Edinburg Saratoga Wind Damage: Tree, wires, and transformer down on Military Road 2:18pm
Fonda Montgomery Wind Damage: Tree down blocking Route 5 just west of winners Circle Restaurant 2:23pm
Fort Johnson Montgomery Wind Damage: Tree down on McDonald Drive 2:29pm
Amsterdam Montgomery Wind Damage: Tree snapped at the corner of Pioneer Street and Harrower Lane 2:30pm
Milton Saratoga Wind Damage: Tree and pole blown down 2:45pm
Malta Saratoga Wind Damage: Trees and wires blown down on Old Post Road 2:48pm
Milton Saratoga Wind Damage: Tree and wires blown down 2:48pm
Wilton Saratoga Wind Damage: Trees and wires down 1/2 mild south of Ballard 2:49pm
Round Lake Saratoga Wind Damage: Large tree branches blown down 3:00pm
Malta Saratoga Wind Damage: 4-6" diameter branches down in Luther Forest 3:06pm
Cambridge Washington Wind Damage: Trees and wires blown down 3:15pm
Cambridge Washington Wind Damage: Trees and wires blown down 3:18pm
Arlington, VT Bennington Wind Damage: Several trees and wires blown down 3:28pm
Shaftbury, VT Bennington Wind Damage: Several trees and wires blown down 3:28pm
Canaan Columbia Hail: Measured 3/4" diameter 3:30pm
Canaan Columbia Wind Damage: Tree down on Route 295 and Queechy Lake Drive 3:33pm
Canaan Columbia Wind Damage: Multiple trees blown down on Tunnel Hill Road 3:33pm
Canaan Columbia Wind Damage: Multiple trees blown down on Route 295 between Route 22 and the MA state line 3:36pm
Canaan Columbia Wind Damage:Tree and wires down along Route 22 and Miller Road and on Lilly Road 3:36pm
Canaan Columbia Severe Wind Damage: 75-85 mph microburst with 50 trees blown down near Routes 22 and 295 - NWS Storm Survey 3:40pm
Richmond, MA Berkshire Severe Wind Damage: 75-85 mph microburst resulted in several road closures do to downed trees - NWS Storm Survey 3:50pm
Lenox, MA Berkshire Wind Damage: Multiple trees down in town and west of town on Route 41 3:50pm
Becket, MA Berkshire Wind Damage: Trees on wires and and a nearby residence 4:05pm
Hinsdale, MA Berkshire Wind Damage: Several large trees blown down on route 8 blocking Washington Mountain Road 4:07pm
North Adams, MA Berkshire Wind Damage: Several Trees blown down 4:10pm
Becket, MA Berkshire Wind Damage: Several large trees down on Route 8 4:10pm
Marlboro Ulster Wind Damage: Trees and wires down 6:45pm
Wappingers Falls Dutchess Severe Wind Damage: 75-85 mph microburst with two main damage areas, the first at Bowdoin Park along the Hudson River where numerous trees were downed. The second area was near Mesier Park where approximately 50 trees were downed with some falling on homes - this along a 1.5 mile path up to 275 yards wide - NWS Storm Survey 6:52pm
Marlboro Ulster Wind Damage: Large tree limb down on Bloom Street 6:53pm
Wappingers Falls Dutchess Wind Damage: Trees and wires down on Mill Street and High Street 6:58pm
Becket Berkshire Flash Flood: Estimated 6-8" of water covering Route 8 near Washington Town park 7:00pm
Hudson Valley Region Dutchess Measured 58 mph wind gust 7:02pm
Red Oak Mill Dutchess Wind Damage: Trees and wires down on South Road and Anthony Drive 7:03pm
Lenoxdale, MA Berkshire Flash Flood: Flooding at the intersection of Housatonic Street and East Street 7:15pm
Becket, MA Berkshire Flash Flood: Flooding on Route 8 7:15pm
Litchfield County Litchfield Pockets of wind damage in Harwinton, Kent, new Milford, Bridgewater, Woodbury Center and Thomaston 7:32-8:05pm


Storm Reports: Wednesday June 30, 2021

Storm Prediction Center Storm Reports For June 30, 2021