Severe thunderstorms likely this afternoon and evening
A morning sounding, gathered via data from a weather balloon launched at the NWS in Upton, New York showed a developing unstable environment — and sufficient wind shear for organization of strong and severe thunderstorms. An approaching disturbance in the mid and upper levels will aid in the development of strong to severe thunderstorms, which will be fueled by a moderately unstable environment throughout the area. Organized thunderstorms will be capable of producing strong and damaging winds, frequent lightning, and very heavy flooding rains.
Additionally, an increase in storm relative helicity and low level shear suggests the potential may exist for downbursts and isolated tornadoes. If individual supercells can form, this threat could be somewhat greater. Storms are expected to develop over Eastern Pennsylvania this afternoon and shift eastward through NJ, NYC, SE NY and CT. With strengthening wind fields, just above the surface, any storm could produce the aforementioned damaging winds and severe-weather impacts.
Morning sounding from the weather balloon launched at Upton, NY.