The Storm Prediction Center has called for a slight risk of severe weather today for the Big Bend area, including Tallahassee. Points west are under an enhanced risk of severe weather, which includes Panama City. The primary threats are damaging winds and a few tornadoes, according to the SPC.
A low is sitting over Louisiana with a warm front dragged across the southeast, based on surface observations. The flow related to the low is helping to usher in wamer, moist air. Further aloft, a shortwave trough is over the western gulf area (see below). This upper disturbance is helping to provide lift across the region. These features are allowing for increased rain chances and thunderstorms today.
ABOUT THE THREAT: PROS
There are some variables that make this severe threat possible.
1) (Some) Turning of the winds with height (shear). The latest balloon launch from Tallahassee this morning shows winds out of the southeast at the surface, but turning quickly to the south roughly 5,000 feet up at 40 knots and changing again to the southwest just a little further up. What does this mean? Turning with height is good for supercell development. This even helps with tornado development. The SRH values are hovering around the 400-mark, which is impressive. The question is whether or not winds at the surface will shift to the south later in the day, limiting any turning with height and, therefore, lessen the threat.
2) Moisture increase. Winds are mainly from the south in the area, which is helping with moisture transport. Yesterday’s rain also helped, too. The current dewpoint in Tallahassee is 66, and it could go up just a little bit more.
3) Upper-air help. The aforementioned trough will help provide a lifting mechanism for rain and thunderstorms.
ABOUT THE THREAT: CONS
1) Cloud cover. The rain and clouds for the last 24 hours will not be beneficial for allowing any instability. The lack of instability will not help with potent thunderstorm development.
2) Possible lack of shear later. This goes back to my first point in the “pros” section. Some guidance is hinting that winds at the surface will be more out of the south or even southwest as time goes on. The RAP guidance run is suggesting SRH values to increase towards the evening, but the thunderstorms might be gone by that point. Also, this is just model data.
There will be a slight threat today for damaging winds and maybe a few tornadoes in the region later this afternoon. It’s important to stay weather aware in the event that the National Weather Service issues warnings today.
Mesoscale models are hinting of a line of thunderstorms moving through later this afternoon into the early evening. I would not rule out a stray storm ahead of this line today. We shall see.
I’ll be keeping an eye on the weather and data through the afternoon.