Wednesday, June 4, 2014

Thursday storm threat is wait-and-see for forecasters

Meteorologists in the Carolinas have a very tricky call to make, regarding the possibility of a severe weather outbreak Thursday.

There actually could be a pair of threats, with the first developing in the early-morning hours and the second on Thursday afternoon.

A clusters of strong thunderstorms was moving across the Midwest on Wednesday morning. That mesoscale convective system (MCS), a fancy word for a batch of storms, is forecast to continue moving eastward during the day, crossing Illinois, Indiana and Ohio. Then the MCS is expect to curve southeast, and that's where it starts getting tricky.

Some of the computer models predict the storms will move across Kentucky, West Virginia and Virginia overnight. Other models predict the storms will curve far enough southeast to affect the Carolinas in the early-morning hours Thursday. That MCS could bring damaging wind gusts, so the track of the storms is important.

The path of the storms also could have a big impact on what happens Thursday afternoon, when a weak cold front is predicted to move into the Carolinas.

The atmosphere in areas affected by early-morning storms will become relatively stable afterwards. That would discourage the development of afternoon thunderstorms.

So if the overnight batch of storms curve far enough southeast to affect the Charlotte area, there are questions about whether the atmosphere really will become unstable enough for another round of stormy weather in the afternoon.  If the MCS stays farther north and crosses Virginia tonight, then the Charlotte area's atmosphere will be plenty unstable in the afternoon.

Justin Lane, from the Weather Service's office in Greer, S.C., said it probably won't be until 3 or 4 a.m. Thursday before forecasters have a good idea on what will happen in the afternoon across the Charlotte region.