Saturday, July 28, 2012

Forecast for Sunday, July 29, 2012

For the rest of this evening, we will be dealing with rounds of showers and thunderstorms. Some of the thunderstorms could produce damaging wind gusts and marginally severe hail. A severe thunderstorm watch is in effect until 10 PM for the entire area. Otherwise, any of these thunderstorms will be slow moving and could redevelop over the same areas. With a very moist atmosphere, there may be areas of flash flooding as a result. Low temperatures this evening are going to be hard to peg with thunderstorms locally enhancing cooling.

The latest guidance suggests that there still may be enough lift for showers and thunderstorms to be at least scattered in nature on Sunday. Therefore, I have gone with scattered showers and thunderstorms. I think the coverage may be a little less than today. Atmospheric movement may be even slower than today and thus any thunderstorm that does form could drop some decent rain amounts and produce localized flooding.

On Monday, it appears that we will not have much of a triggering mechanism for thunderstorm development, but that there may be enough lift by old outflows and a front creeping southward in a humid environment for very isolated thunderstorms in the afternoon and evening hours. I think most of the region will see partly sunny skies and remain dry. We will keep an eye on it.

For Tuesday through Friday, a warm front will be moving northward and meandering across our region. This may act as a triggering mechanism to develop showers and thunderstorms each and every day. We may also be contending with a series of weak cold fronts Wednesday through Friday. There is the possibility of some severe weather during this time frame as the Philadelphia Metropolitan area should enter the warm and unstable sector.

For temperatures, the MOS guidance and thicknesses suggest values of 87-89 degrees for the next seven days without much variation. It is possible that later runs suggest Wednesday through Friday, may reach into the 90 to 92 degrees if we see more sun and less t-storms. However, dew point temperatures in the upper sixties are expected throughout the week signaling an uncomfortable, humid period ahead.