Saturday, August 25, 2012

Forecast for Sunday, August 26, 2012

Tonight, an area of low pressure will continue to drift northward with a weak warm front. This low pressure area will increase the onshore flow leading to extensive clouds and periods of showers. There could be a few embedded thunderstorms with this feature across Southeastern New Jersey and Delaware. Any thunderstorm will have access to modest low level shear which may pose a low risk for a few isolated and brief funnel clouds, tornadoes, or waterspouts. This has already occured across the Eastern Shore of Maryland and Southeast Virginia. Right now, the greatest shear is located across the Delmarva and points south of there and that is where the best tornado potential will be. The driest conditions will be in our northern areas tonight where very little shower activity may occur. In fact, it has been partly cloudy in the Poconos much of the afternoon and those breaks in the clouds should continue into this evening.

Eventually, this low pressure area will slowly diminish and weaken overnight. Then a weak trough will be over the region Sunday into Sunday Night producing additional scattered showers with embedded isolated thunderstorms across the region. A cold front is expected to move through the region on Monday, pushing offshore by Tuesday. This will bring another chance for scattered showers and thunderstorms. While a few breaks in the clouds are possible during this period, there should be more clouds than sunshine.

An area of high pressure will build into the region during the late week period. At the same time, Issac will likely be making landfall (second landfall if it hits the Florida Keys) somewhere between Louisiana and Panhandle of Florida. The computer model guidance has not yet come to a good consensus on where this Gulf Coast landfall may be. Until the landfall point is really narrowed down with confidence, the track of the remnants of Issac remains to be seen. The strength of Issac at landfall, based on the track it takes over the Gulf of Mexico, will also determine whether it can impact the area of high pressure building over our area late in the week. Some huge adjustments to our late week forecast may be necessary if Issac’s remnants threaten our region. We will also keep an eye out for additional tropical development out in the Atlantic since some of our long range model guidance suggests that another tropical wave may turn into a tropical cyclone and head westward.