Stormy Weather Possible for the Northeast

Surface analysis courtesy of Intellicast.

A cold front that is situated over Southern Quebec through Central New York/Pennsylvania and into the lower Ohio Valley will help to set up favorable conditions for some severe storms in the New England States, Northeastern Pennsylvania, and the Central Appalachians this afternoon. An elongated trough of lower pressure sits over this entire area, currently, which will help decrease heights as the day progresses.

Even though mid-level lapse rates should remain weak, a few other factors will play an important role in setting the stage for storm development in the slight risk area today. A combination of an air mass rich in moisture and moderate daytime surface heating should help CAPE values increase to about 1000 J/Kg in central Maine to larger values of about 2000 J/Kg in Pennsylvania and New Jersey.

Development of storms will be seen initially along the outflow boundary from overnight storms and the lee trough in the central/northeast Pennsylvania and southern New York areas. Expect storm development later this afternoon along and ahead of the cold front boundary as it makes its way through the projected slight risk area. Storms should be expected to develop in the Mid-Hudson Valley and eastward into central/eastern New England.

Storms should develop into lines/clusters with the primary threat being locally damaging wind from embedded bowing segments. A few isolated tornadoes cannot be ruled out due to the strength of the 700 mb flow (40-50 kts) and the moisture rich lower levels of the atmosphere. Storms should merge into a squall line and diminish later tonight.

Overview of the projected slight risk area for 9/6/2014 courtesy of Storm Prediction Center.