Looking at some of the information coming out of the SPC and the models, it would appear as if we are about to see and outbreak of severe weather over the northeast on Saturday. The ingredients are in place for significant, and widespread wind damage and tornadoes. Moisture and instability will be strong with CAPE values over 1500. Also, there will be plenty of wind shear and change of wind direction with height across eastern PA, NJ, eastern NY, CT, western MA, and southern NH and VT. The jet stream will be moving very fast at 70 knots in the mid-levels of the atmosphere and potentially increasing from there as this severe weather event unfolds. As far as tornadoes are concerned, it will all depend if discrete supercells form out ahead of a developing squall line which will form along the cold front. If they do develop out ahead of the main squall line, they will have the ability to draw from very high instability and will have an easier time taking advantage of the environment ahead of the squall line as opposed to if they are located in an area with numerous thunderstorms, because they will have strong competition from other thunderstorms. Certainly going to be a rough day for cities like Scranton, Albany, New York City, Hartford, Philadelphia, Harrisburg, Springfield, and even as far north as Burlington, Vermont.
Sep 07 2012