A few severe weather notes

Latest visible satellite shows some breaks in the clouds, especially over south Alabama. A few even farther north.

The 60+ dewpoints have now reached as far NE as a line from Tupelo to Demopolis to Enterprise, and those dewpoints will continue to advect northeastward. Surface winds may only be 10-20 mph, but the VAD wind profile from the BMX radar shows much higher winds just off the surface, and those winds are increasing. 45 knots (55 mph) at 4,000 feet is pretty high, and that is transporting warm, moist air in here rapidly. Air currently in southern Mississippi should be here by late afternoon. Also, note the winds veering from southwest near the surface to west aloft…that along with the shear is helicity, for rotating storms.

The strongest wind shear will start to pull east of us by afternoon, since low-level winds will veer some and the winds at 4,000 feet will weaken. But, the shear will probably not move out fast enough. Storms will start to develop quickly ahead of a wnd shift/dryline from eastern Arkansas into Louisiana. There is no big forcing mechanism for widespread convection, but with temperatures warming into the 70s, any cap will go away, and expect storms to develop between noon and 2 pm. In the high-shear environment, once storms develop, they will quickly become intense. This looks more like a supercell environment, at least ahead of the cold front that will come through this evening, so tornadoes will be a problem today.

Anywhere south of US-278 has a mentionable risk of tornadoes, and pinpointing the exact location of severe storm or tornado development today is difficult, with the rapidly changing shear and instability. The indices that combine shear and instability, like the EHI, and the significant severe parameter, point toward the I-20 corridor. So, if you live anywhere in Alabama, you need to have a source of weather information today. This situation looks worse than it did last night.

I’ll be headed out with Brian Peters on a storm chase in the next hour, we just have to decide whether to stay with our original plan and go to Selma, or whether we want to stay farther north.

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