Severe weather analysis – 1045 am

…TORNADO WATCH FOR NW 1/3 OF ALABAMA…INCLUDING BHM, TCL, MSL, HSV…

The system is coming in faster than we had anticipated earlier.  A little sun has allowed temperatures to climb to near 80, and with dewpoints near 70, the atmosphere has already become unstable, with CAPE values 500 to 1,000 J/kg over north AL now.  CAPE may reach 1,500 J/kg this afternoon, with more sun and cooling temperatures aloft.  The stronger dynamics are to the north with this system, with a few tornado reports but lots of damaging wind reports, over IL, IN, KY, and TN.  However, with plenty of wind shear across north Alabama (helicity above 400 m2/s2), almost any storms out by themselves will likely rotate, bringing the possibility of tornadoes. 

The main line of storms (line 3 in radar picture below) is still way back in eastern Arkansas, and when it finally moves through by late today it will bring damaging wind, and maybe a few tornadoes, similar to Monday morning early.  However, a new line of intense storms has formed out ahead of it (line 2).  Line 2 is breaking into supercells, meaning it is more likely to produce tornadoes, and numerous tornado warnings have been issued in northern Mississippi.  This is the line we are most concerned about now, as the storms are more discrete.  Some of these storms may start to affect NW Alabama, (Florence, Moulton, Hamilton, Sulligent, Winfield, Aliceville, Fayette) by noon.  Line 1, already in NW Alabama, looks weak so far, but we’ll have to keep an eye on it also.

Have a source of weather information nearby all day today and into this evening.  This whole thing likely will not be over until after sunset.

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