Saturday September 8, 2012 dawned a warm and windy day across Upstate Eastern New York, and particularly in the New York Capital Region. A warm front had passed through the region in the pre-dawn hours, allowing for a southerly wind to increase in the low levels of the atmosphere, veering to a westerly to southwesterly direction in the middle and upper levels of the atmosphere. Wind speeds were quite high as winds between 3,000 and 5,000 feet above ground level were near 50 MPH at times.
This strong southerly low level flow drew increasing amounts of low level moisture into the region. The evidence of this being that dewpoint temperatures had risen into the mid and upper 60’s across the region by early morning, and would peak near 70 degrees by afternoon as a potent cold front approached the region early in the afternoon hours.
As the front crossed central New York, and approached the Capital Region and vicinity, the ingredients were set for a potentially damaging outbreak of thunderstorms. This was due to both the wind profile of the atmosphere, with both high speeds and clockwise ‘turning’ of the wind direction through the lower and middle levels, known as directional wind shear.
Breaks in the cloud cover that blanketed most of the region during the morning hours provided for a period of moderate to strong atmospheric heating in advance of the cold front. This heating further destabilized the atmosphere, and would allow for the development and maturation of a squall line of thunderstorms over central and western New York. This squall line moved rapidly eastward, and impacted the Capital Region with thunderstorms that produced gusty winds and heavy rainfall.
The region was placed under a tornado watch by the Storm Prediction Center in Norman, Oklahoma, as it forecasters determined that there was the potential for tornadic thunderstorm development. Though no tornadoes were reported in the Capital Region, or anywhere in upstate Eastern New York for that matter, two tornadoes touched down that Saturday morning in New York City boroughs!
Several reports of trees and wires being down were received by the National Weather Service office in Albany, NY. In general, winds gusted to between 30 and 50 MPH, as reported by spotters and equipment in the field, across the region as the squall line passed through the area between 3 PM and 6 PM. Some notable wind gusts included a 54 MPH gust at the Dutchess County Airport, 47 MPH near Glenville, NY in Schenectady County, and 40 MPH at the Albany International Airport.
Rainfall amounts generally averaged between a half inch to an inch and a half. East Jewett in Greene County picked up 1.51 inches, while Brunswick in Rensselaer County received 1.36 inches, and the Albany International Airport dented into its yearly rainfall deficit with 0.51 inches of rainfall during the event.
Sources: Data for this report was excerpted from the National Weather Service forecast in Albany, NY and from the Associated Press.
National Weather Service Storm Summary Page for 9/8/12
Local Storm Report Product from National Weather Service Albany, NY for 9/8/12
Radar Imagery and Loop of 9/8/12 Squall Line