Thursday, July 26, 2012
Nasty Day Ahead
It's going to be a rather busy weather day throughout the region -- thunderstorms are approaching this morning from the northwest, west, and more storms will be likely later on today. We're under a slight risk of severe weather in the city, with a moderate risk of severe weather roughly along and northwest of a line from New York City to Allentown to Harrisburg.
Early morning radar shows a batch of storms crossing to our north this morning as the MCS that was over Ontario last night in our discussions on Facebook is now drifting southeast just to our north. Those storms will scatter through the northern suburbs and parts of the Lehigh Valley in the 6-7:30 timeframe given their current track and movement. More thunderstorms, located out near Johnstown and Pittsburgh as of 5 AM, would reach us around 8-9 AM if they hold together.
Once the morning thunderstorm threat passes through, heat and humidity will quickly push northeast out in advance of a cool front that's sliding down from the north. Temperatures will quickly jump into the 90's this afternoon on gusty south and southwest breezes that will exceed 25 miles per hour in gusts. The midday period provides a lull between the morning round of thunder and the afternoon "main show" that will set up to the city's north and impact much of the Northeast with a gusty wind event. Thunderstorms fire later on, many of those will be severe should they fire up.
The combination of heat and humidity will push heat index values to 100-105 around the region. Today's high of 95 is based on getting enough clouds to prevent a full blown blast furnace at temperatures -- the NAM suggests a run at 100 and if we dodge morning thunderstorms in the city and are sunny for much of the day we could nudge the upper 90's in the city but there may be just enough clouds and storms around this morning to keep a bit of a lid on temperatures in place.
We'll have more on thunderstorm timing, track, specifics a lil later this morning.