SEVERE WEATHER UPDATE

11PM Update. Tonight’s NAM continues to show most of the heavy/severe thunderstorm activity between 7 and midnight Wednesday evening. However, tonight’s  WRF models suggest the possibility of scattered showers and thunderstorms any time during the afternoon as well, with the heaviest in the evening. It will be an active day weather-wise.

For tonight (Tues), the models have no showers moving into Philadelphia, but current radar shows some storms in upper Montgomery county moving eastward.

Looking at the latest Rapid Update Model, there are enough parameters that would support the showers moving into the immediate PHL area.  I guess we’ll see whether they fall apart as predicted or hang together.  Nothing major expected.

As for tomorrow, Wednesday, the remains of Barry will be moving through our area late afternoon and evening.  Some of the severe parameters are fairly impressive and the models have been predicting that the Philadelphia area will be a bullseye for the heavy activity.

Some models have storms breaking out in the northwest suburbs as early as 4-6 PM.   Most of the severe weather and heavy rain looks to occur between 7 PM and midnight.  Models are predicting about 3 inches of rain with locally higher amounts.  Some severe parameters (like “helicity” and “vertical shear”) become very impressive in central New Jersey during the late evening hours. Tornados are associated with these levels of shear and helicity.

NAM predicted vertical shear 12 midnight Wednesday. (Dark Brown >20 vertical shear)