Monday, September 02, 2013

A Sign Of A Gradual, Slow, Change Of Seasons

We alluded to the comfortable mornings ahead later this week -- and wanted to throw another log on the fires of comfortable weather to point out the possibility of the first frost of the incoming cool season in Bradford and other typically cold locations in Northern Pennsylvania on Friday morning.

The GFS shows this possibility on Friday -- 30's along the northern tier of Pennsylvania and into the Appalachian spine, with lower 30's (subfreezing) air in the blue circle right along the border. Granted, this is the raw GFS...and a model that historically has a bias towards the cold side...but it is a sign that the incoming air mass will be much more refreshing than what we've seen in a couple of weeks around here...especially after the reinforcing front slides through on Thursday to push additional cool air into the region.

Even in the Philly metro, the GFS is showing the possibility of 40's north/west of the city early Friday morning. It may be a bit aggressive on the level of crispness unless you're in Quakertown or some of the cooler hills around town, but still a much more refreshing sign of cool ahead.

The European model is much less aggressive on the possibility of cool -- only showing 40's across Northern Pennsylvania, 50's for much of the rest of the state. Again, the GFS is a bit more aggressive on cold setups than the Euro...so even splitting the difference between 40's and 30 yields the possibility of upper 30's/near 40 type lows near Bradford. Not quite freezing, but still cold enough for early September.


For a point of comparison, Bradford's record low on Friday morning is 30 degrees...so the GFS would suggest near record cold up there if it indeed is right.  Even if the model is a bit too aggressive on the level of chill ahead, Friday morning does appear to be the most likely morning for chill in the week ahead and perhaps the coolest morning we've seen in a while even around here.