The atmospheric ingredients are coming together for supercell thunderstorms to develop into the evening hours tonight. We have a stalled front, warm and humid air and a potent vorticity maximum that will be arriving from the northwest this evening. Here’s the severe weather outlooks from SPC.
Overall Severe Risk Tornado Risk
Severe Wind Risk Large Hail Risk
Of particular note is the severe hail map where there is a blacked hatched area you see right over the Western Carolinas. This marks the area were there is a 10% or greater probability of 2” diameter hail or larger within 25 miles of any point. Based on that data here are the threats today based on our First Warn severe weather indices. Hail & wind is the main concern, but with super cells isolated tornadoes are always possible. The tornado risk is highest in the warmest air near the stalled front, but the good news is we don’t have the crazy helicity values you like we saw in April many times.
Based on the HRW model’s future radar and sounding data the storms will develop first in KY and TN then move into the Carolinas. The late evening time frame of 6-8pm looks like the time things get going, but they could then last into the morning hours Wednesday.
The set-up is very similar to the large hail event we saw back on April 9th, 2011. We have a stalled front, warm unstable airmass and a strong mid level disturbance. Which means I would be most worried about large hail and damaging winds but isolated tornadoes are also possible. I expect a watch of some kind will be needed late this afternoon or evening with subsequent warnings. Stay tuned to NewsChannel 36 for the latest on this severe weather event.