…SEVERE THUNDERSTORM WARNING JUST ISSUED EXTREME NW ALABAMA…
A line of severe thunderstorms is approaching NW Alabama at this time. The air gets a little more stable, and the shear decreases somewhat, as one moves SE in central Alabama, so hopefully the storms will weaken as they move in.
It may be a timing game tonight. Wind shear slowly increases over the NW half of Alabama, and dewpoints increase while temperatures drop little (it’s a hot night). The storms are moving faster than we expected, and will enter NW Alabama soon. Tornado warnings have been issued in Mississippi, but most of the reports over the past 2-3 hours have been damaging winds and hail, not tornadoes. If the storms keep moving at a rapid pace, they may be able to move in here before the atmosphere has time to destabilize, allowing them to weaken. As Bill notes below, the storms seem to be slowing down a bit. One more fly in the ointment…there is a pocket of DRIER AIR at low levels from Clanton south into the Gulf…likely due to air descending out ahead of the main storm system. So, it is difficult to get a handle on how unstable the air will be as the storms move in tonight.
One thing that usually happens at night is that wind shear increases, and that is likely tonight.
The bottom line is this. The air is already unstable and sheared enough to allow the storms to continue into NW Alabama as severe storms over the next 2 hours, with damaging winds and large hail the main threat, and we can’t rule out tornadoes. But, this system is not like the one on April 27, not even the morning one that day. In HSV, TCL, Cullman, and BHM, expect storms to move in well after midnight. Depending on how much moisture moves in here over the next 3 or 4 hours, the storms could be severe, producing damaging straight line winds up to 70 mph and large hail. We can’t rule out a tornado, but this system is more likely to produce weaker tornadoes if any, not the long-track strong ones we saw in the outbreak. Those are still serious, especially in mobile homes.
So, in BHM metro, leave the weather radio on when you go to bed, or set an alarm and get up around 2 am and check the weather. Bill and I will be posting throughout the night (mainly Bill). In TCL, Jasper, and Cullman, set your alarm a little earlier, maybe 1 am. If a tornado warning is issued, go to a safe place at once. In a mobile home, leave it and go quickly to a more substantial structure.
