Severe Weather Outbreak
An outbreak of severe thunderstorms produced frequent cloud to ground lightning and thirty two reports of wind damage across eastern New York and western New England through the late afternoon and evening hours of the 9th.
An oppressively hot and humid air mass flowed into the Northeast through the day with temperatures surging into the low 90s and dewpoints climbing to around 70 degrees by the early afternoon. The heating helped create a considerable amount of potential energy in the atmosphere that would be used to fuel the thunderstorms late in the day.
A cold front and associated wind shift line running well ahead of the front acted to initially focus thunderstorms across northern New York and northern New England. Moderately strong mid level winds and sufficiently cool air aloft combined with the strong heating and high surface moisture availability to produce several rounds of severe thunderstorms across the far north through the late morning and early afternoon. In fact, two brief F-0 tornadoes (Winds to about 70mph) occurred in St. Lawrence county.
The atmosphere over the Capital Region and adjacent western New England was more strongly capped through much of the day. In other words, a layer of sufficiently warm air aloft was present to prevent thunderstorm updrafts from forming, until very late in the day. This "Cap" allowed surface heating to reach it's full peak between 4:00 and 5:00pm. As boundary layer temperatures climbed into the 90s, high enough to break the cap, thunderstorms fired. Initially, a broken line of storms formed from a line that extended from near Utica to Binghamton. As that broken line encountered outflow from the thunderstorms occurring across northern New York they began to expand and intensify as they moved into first Fulton and Montgomery counties. Since winds were fairly unidirectional with height in the atmosphere shear parameters for supercells was absent. Instead, the flow supported severe multicell type thunderstorms which characteristically produce localized downbursts of damaging wind.
In this case, the wind damage that occurred in the region was of a very localized nature coming from collapsing multicell storms, rather than widespread wind damage that would be more typical of a well organized squall line or series of supercell storms. Nevertheless, downburst winds reached or exceeded 70 mph in areas like Ghent, in Columbia county, where extensive damage to trees was done in the evening.
Hail turned out not to be a great threat even though Doppler radar indicated that hail was present aloft in many of the storms. The degree of heating in the atmosphere meant the hail was high up in the storm allowing most of it to melt as it fell from the cloud. In fact, no reports of severe hail were received across the region throughout this thunderstorm event.
Severe weather began in Fulton county, near Gloversville around 5:20pm and came in two lines, meaning many areas were hit at least twice with strong thunderstorms over a short period of time. It took until approximately 9:30 pm for all of the severe weather to clear the southern and eastern most counties in the Channel 6 coverage area. At the height of the outbreak approximately 30,000 homes were without electricity in the region.
Wind Damage Reports from the June 9th Severe Weather Outbreak