As of 7:30 AM this morning, a good chunk of central Alabama is under a Tornado Watch. Radar loops have been quite impressive showing high DBZ and velocity values. Main threat posted with thunderstorms this morning will be gusty winds and large hail. Over the past few scans however, there has been a somewhat decrease in intensity. As of this writing only one Severe Thunderstorm Warning is in effect for Shelby County. The latest real-time hazard map is available at awpwx.org/hazards
For the afternoon and evenings hours, the SPC has expanded the Moderate Risk further into Tennessee/Kentucky, and has placed the Huntsville Metro under it as well.
The hi-res model data will be the go-to for this event, as it handles severe weather events incredibly. After this morning’s storms, it shows thunderstorm re-development right around noon:
By 4:00 PM, you can see more widespread supercells forming:
By 8:00 PM all activity is focused across northeast Alabama:
SCP (Supercell composite) values at the times mentioned above:
STP (Significant Tornado Paramater) values at the times mentioned above:
As you can see paramaters spike up during the day as we get more daytime heating. I am awfully concerned with the 6:00-8:00 PM time frame across east/northeast Alabama where STP values max out.
Again, given these paramaters, there is the potential for severe thunderstorms all across the state, and given the shear at the surface a few tornadoes cannot be ruled out – one or two which could be strong, long-tracked.
I do anticipate a Tornado Watch being issued before the lunch hour to alert everyone that conditions are favorable for tornadic development. It’s not my call to determine if it will be a PDS Watch or not, nor is it my call to determine if an upgrade to High Risk will take place, nor is it my call to give a TORCon for a specific area (give me a break).
Bottom line, have a way to receive Watches and Warnings today across the entire state. Know where to do, and where to go, and everything will be just fine. Don’t be scared, be prepared.