Friday Afternoon Severe Weather Update – February 24, 2017

We have the warmth already in place for severe thunderstorms thanks to those gusty southwest winds, with temperatures nearing the 80º mark across south-central Kentucky.

3:35pm CT Observed Temperatures. (Kentucky Mesonet)
3:35pm CT Observed Temperatures. (Kentucky Mesonet)

And a quick check of the White Squirrel Weather Nestcam at WKU shows clouds on the increase as storms continue to build to the west and northwest of the area.

(White Squirrel Weather)
(White Squirrel Weather)

Radar at this hour is showing scattered showers and thunderstorms beginning to pop across southern portions of Indiana and Illinois, moving off to the north and east.

Evansville radar valid at 3:47pm CDT. (Screenshot by me from Radarscope)
Evansville radar valid at 3:47pm CDT. (Screenshot by me from Radarscope)

These storms have begun to bubble up inside the SPC’s slight risk area which includes the Bowling Green area through tonight. The storms are moving into the Enhanced Risk area off to our north where the probability of severe weather is a little bit higher due to their better dynamics. In fact, a severe thunderstorm watch is already in effect extending down through southern Indiana.

Today's Severe Weather Outlook as of 2:00pm CT. (Storm Prediction Center)
Today’s Severe Weather Outlook as of 2:00pm CT. (Storm Prediction Center)

ww0037_radar_big

All of that is ahead of a cold front stretching down into Arkansas from a surface low located up in northern Indiana.

SPC Surface Mesoanalysis with radar underlayed...and horrendous drawing of surface low and trailing cold front by me.
SPC Surface Mesoanalysis with radar underlayed…and horrendous drawing of surface low and trailing cold front by me in the macOS Preview application.

The airmass ahead of this front is fairly unstable for the month of February with CAPE (potential energy) values between 500-1000 j/kg, in other words conditions favorable (when combined with the ample wind energy in our area) for a few severe thunderstorms. The only thing working against that in most of Kentucky is a strong cap, represented by the blue shaded areas on the map below. A cap is formed where there is a layer of warm air above the surface that prevents the air from rising and forming thunderstorms.

SPC Mesoanalysis CAPE and CIN. (Storm Prediction Center
SPC Mesoanalysis CAPE and CIN. (Storm Prediction Center

Eventually that cap will break and allow thunderstorms to form over our area. Current models suggest storms will begin as isolated cells and merge into a line as it moves into our area between 8 and 10pm. The greatest threat with these thunderstorms will be damaging straight-line winds but there’s a smaller chance for large hail and we can never completely rule out the possibility of a small spin-up tornado along the line.

HRRR simulated radar valid from 4pm until midnight showing storms in here in the late mid-evening timeframe. (Pivotal Weather)
HRRR simulated radar valid from 4pm until midnight showing storms in here in the late mid-evening timeframe. (Pivotal Weather)

After the storms tonight, we cool considerably behind the front and Saturday will be the coolest day we’ve seen in some time, highs not making it out of the 40s!

That’s it for now, be sure to follow @WxOrNotBG and @WKUweather on Twitter and like Landon Hampton on Facebook for the latest on tonight’s severe weather threat.