There have been a few reports of tornadoes in Arkansas, with one passing over the National Weather Service office near Little Rock, doing some damage to nearby buildings.
The forecast for Alabama has gotten a little more difficult, as the latest NAM shows the system coming through faster than previously forecast, with the main squall line reaching NW Alabama by noon and MGM by sunset. The GFS is still sticking to the original timing, with the main line reaching NW Alabama around 5 pm, and Anniston and Montgomery by 1 or 2 am. The NAM is probably allowing the squall line to determine its own dynamics a little more, which may mean a larger chance of damaging winds; as opposed to the GFS, which is allowing the large scale flow to control the squall line, and means more time for destabilization ahead of the line and isolated tornadoes. The NAM could be right, but the GFS solution looks more likely at this point.
Either way, dewpoints over southern MS and eastern Louisiana are between 65 and 70, and strong SW winds will transport that air into north and central Alabama this morning. Dewpoints in BHM should reach the mid to upper 60s by early afternoon. It is still uncertain as to how much cloud cover will move in this morning. Temperatures should rise at least into the lower 70s, but with sunshine it could quickly reach 75 to 80. CAPE values without sunshine will reach 1,000 J/kg, but with sunshine in the morning they could reach 2,000. Hard to say. Both models still indicate plenty of wind shear for rotating storms.
Bottom line…best guess right now would be that scattered thunderstorms will develop, maybe as early as noon, and some of these may become severe today. If the worst-case scenario plays out, with a slower front, sunshine warming temps to 80, and a surface low on the front near Tupelo, we will really have to watch out for tornadoes this afternoon. The squall line will then move through, probably around 7-10 pm in BHM, with damaging winds, large hail, and isolated tornadoes possible. Total rainfall may exceed 1″ in many areas.
The weather situation will develop rapidly today, so be sure and have a NOAA Weather Radio or other source of weather imformation nearby at all times. While this does not have the look of a “major” tornado outbreak (unless the worst-case scenario occurs, which is unlikely), it is a system that may produce tornadoes and needs to be taken seriously.
JB, Bill, and everybody will keep the blog updated, and if tornado warnings occur, James, Jason, Ashley, and I will be on TV.
