New Watch Possible Across Northern Alabama

From the SPC…

MESOSCALE DISCUSSION 0283
NWS STORM PREDICTION CENTER NORMAN OK
0603 PM CDT SAT MAR 26 2011

AREAS AFFECTED…NERN MS AND NRN AL

CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE

VALID 262303Z – 262330Z

A NEW WW MAY BE NEEDED DURING THE EARLY EVENING ACROSS MAINLY NRN
AL.

LATE AFTERNOON SURFACE ANALYSES SHOWED AN AREA OF LOW PRESSURE HAD
FORMED AND WAS TRACKING EWD INTO EXTREME NWRN AL ALONG A SURFACE
BOUNDARY WHICH EXTENDED E THEN SE AS A WARM FRONT INTO NRN TO ERN
AL. MEANWHILE…A COLD FRONT TRAILING SWWD FROM THE AL LOW WAS
MOVING SLOWLY SWD THROUGH NERN-WEST CENTRAL MS. OF PARTICULAR
CONCERN FOR NEW TSTM DEVELOPMENT IS THE RECENT DESTABILIZATION OF
THE AIR MASS ACROSS NRN AL WHERE LATE DAY SURFACE HEATING/LOW LEVEL
MOISTURE ADVECTION HAS OCCURRED AS SURFACE WINDS HAVE BECOME SSWLY
WITH THE NWD MOVEMENT OF THE WARM FRONT. OBJECTIVE ANALYSES
INDICATED THE WARM SECTOR IS MODERATELY UNSTABLE WITH MLCAPE
1000-2000 J/KG.

THE COVERAGE/INTENSITY…PER REGIONAL RADAR IMAGERY…OF ELEVATED
TSTMS ONGOING FROM SRN MIDDLE TN TO FAR NRN MS SUGGESTS THE FORCING
FOR ASCENT ATTENDANT TO A SHORTWAVE TROUGH TRACKING INTO THE OH
VALLEY/ENTRANCE REGION OF 70 KT WLY MIDLEVEL JET IS SUFFICIENTLY
STRONG. THUS…AS THIS FORCING PROGRESSES EWD ACROSS THE NRN EXTENT
OF THE WARM SECTOR…CELLS ALREADY DEVELOPING ALONG THE COLD FRONT
IN NERN MS AND THE WARM FRONT OVER NORTH CENTRAL AL SHOULD BECOME
MORE ROBUST. EFFECTIVE BULK SHEAR AROUND 50 KT AND ENHANCED LOW
LEVEL SHEAR /EFFECTIVE SRH 200-300 M2 PER S2/ WILL SUPPORT
SUPERCELLS WITH AN ATTENDANT TORNADO AND LARGE HAIL POTENTIAL.

..PETERS.. 03/26/2011

…PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT…

ATTN…WFO…BMX…HUN…MEG…

Category: Alabama's Weather, Severe Weather