Saturday, August 24, 2013

Forecast for Sunday, August 25, 2013

The GFS LAMP guidance was relied on for the low temperature forecast for this evening. The Poconos tonight should see low temperatures in the upper forties. Philadelphia will see low temperatures in the lower sixties. Areas outside of the city will likely see low temperatures in the fifties. So a bit of an August chill out there tonight under clear skies!
Sunday looks absolutely fantastic with a strong ridge of high pressure in control of our weather. Abundant sunshine is expected and the flow suggests low humidity. Highs should be in the lower to mid-eighties with cooler temperatures in the higher terrain and at the coast.
Monday is shaping up to be a transition day. Clouds should increase along with the humidity. Late in the day, a few showers and thunderstorms are possible.
High pressure sinks to the south for Tuesday and Wednesday. We will be on the northeastern periphery of the high and this doesn’t usually guarantee dry weather. In fact, we may end up being in the “the ring of fire” as thunderstorms could very well initiate around the edges of this area of high pressure as capping looks weak. The models are hinting at some Mesoscale Convective Systems or organized areas of thunderstorms that sustain themselves for a considerable amount of time impacting parts of the area. These systems always present forecast challenges in our region. Sometimes the models are too vigorous and they don’t materialize and sometimes the models weaken them too soon and they survive into our region. There is some uncertainty nevertheless including on the exact timing. An early round of thunderstorms may also use up most of the energy and the atmosphere may not recover for an afternoon or evening round of storms. There is certainly going to be a lot to iron out between now and mid-week.
Meanwhile, a cold front will approach the area on Wednesday and slow down considerable. A second cold front will swing through on Thursday. There could be an isolated thunderstorm on Thursday as a result of the second cold front.