A big cluster of thunderstorms was inching across the Alabama-Georgia state line just after 7:30 this evening. The large cluster of storms responsible for several warnings earlier in the afternoon in Georgia was poised to move into and across portions of Cherokee, Cleburne, and Randolph counties. The large complex was moving steadily westward at about 25 mph.
One of the toughest jobs is to forecast the continuation of a convective complex. It does not at this writing appear to be showing any significant signs of decreasing. Based on the current movement, it would seem that the storms should reach Calhoun, Clay, Etowah, and parts of Talladega counties within the next hour.
There has been some tremendous lightning with these storms as well as some heavy downpours. One hour rainfall totals from the various Doppler radars suggest isolated amounts of 3 to 4 inches are possible with widespread amounts of one to two inches. While the rain is beneficial, it’s possible that this complex could create some flash flooding. Since it is moving along I-20 plus over other US and local highways with some hilly terrain, motorists should be especially cautious with night coming on. Many flash flood deaths occur when motorists drive into flooded roadways that are very difficult to identify.
I’m certain that additional posts will be made here this evening and well into the night as these thunderstorms move and change.
-Brian-
PS Added about 8:00 pm
I just finished looking at additional data, and the area from about Birmingham eastward to the leading edge of the convective complex showed lifted indices of -4. There was also an axis of SBCAPEs running from that complex across the Birmingham area into West Alabama between Hamilton and Fayette. So it would seem that there is no immediate reason to believe that this complex will dissipate in the near future. The Birmingham NWS office issued a Significant Weather Alert for many of the counties I mentioned above just before 8:00 pm.
