Wednesday, July 25, 2012

Excessive Heat Warnings Tomorrow

While we should avoid a record high tomorrow in Philadelphia (101 is the record, set in 1892), it will be a hot and dewpoint-rich day tomorrow, the combination of which will push heat index values to around 100 to perhaps 105 in the worst of the worst locations around town. The National Weather Service has placed the Philly metro in an excessive heat warning for tomorrow afternoon, with a heat advisory out for Berks County to our west, Central and South Jersey to our east and southwest, and the rest of Delaware to our south.

Tomorrow and Friday will be rather hot and humid days, with tomorrow probably a little worse from a humidity standpoint than Friday will be.

The fly in the ointment tomorrow may be some morning thunderstorm activity -- which the higher resolution models try to shoot through parts of the region in the pre-dawn or early morning hours tomorrow based on thunderstorm activity that may develop later tonight in Ohio or Northwestern Pennsylvania. If that does indeed develop and move through in the morning hours, it might knock temperatures back a notch or two and prevent a 100 degree heat index from happening in and around Philadelphia. However, it's not a lock by any stretch and since it's not, it's best to be prepped and have the proper warnings out.

Of course, these heat warnings are merely slaps in the face given the threat for severe weather tomorrow afternoon and evening around portions of the region.