Daweathablog

Charles E. Roop giving his own forecasts, weather discussions, photos and adventures for the Starkville, MS area, Florida, and beyond.

Saturday, October 17, 2009

Cooler Weather is Here!

Just got back in town from Orlando this evening after leaving Gainesville Friday to temps well above normal and very muggy. When we arrived in town, the temperature difference was highly noticeable. I was almost shocked. It has been so long since it has been this nice.

Now...

It's 52 degrees at Gainesville Regional Airport at the moment and 55 degrees at my apartment in southwest Gainesville. The cold front that passed Friday is just south of the Florida Keys while the low is offshore near 30 degrees north latitude. Dewpoints remain really low (in the 40s) with winds mostly from the northwest in inland Florida and points north. There is some high cloudiness to our north over southern Georgia.

Tonight...
Clear skies are over Gainesville with temps in the 50s, but the winds at 15 mph (sustained, 25 mph gusts at KGNV), it feels colder. The cloudcover over south Georgia is on it's way towards the area (it can been seen on the infrared satellite imagery and the last few frames of the visible).

There are two things that can make this forecast tricky tonight:

1) The wind. Wind may make it FEEL cold, but it could help keep the air temperature warmer than it would be if the winds were calm. This is because winds stir up any heat at the surface can keeps radiational cooling in check.

2) Cloudcover. This also keeps radiational cooling in check. It helps keep heat remaining in the troposphere (where all the weather occurs in the atmosphere) to escape back into space. In other words, cloudcover acts as a blanket over us and helps keep things warmer than it would be with clear skies.

NWS-JAX is calling for 41 tonight in Gainesville. However, am beginning to question this forecast a little. Cloudcover to our north may dissipate (as it is starting to show in the IR sat imagery). However, guidance models seem to have winds remain at around 10 knots (11.5 mph).

For tonight, partly cloudy skies for later on. Otherwise, mostly clear. I'm going to be slightly conservative at the moment and call for a low near 44.

If you plan on celebrating the win against Arkansas tonight (WoOt, Gators!) or going downtown, bring a nice coat.

Sunday looks really nice with clear skies and a high near 65. Sunday night might be the coldest night of during this spell. I'll post my predictions tomorrow evening on Twitter and Facebook.

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