From SPC…
MESOSCALE DISCUSSION 1578
NWS STORM PREDICTION CENTER NORMAN OK
1252 PM CDT THU JUL 16 2009
AREAS AFFECTED…PARTS OF CNTRL AL/MS
CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE
VALID 161752Z – 161845Z
POTENTIAL FOR ISOLD STRONG/SEVERE WET MICROBURSTS WILL INCREASE THIS
AFTERNOON ACROSS CNTRL AL/MS. TRENDS WILL BE MONITORED FOR A
POSSIBLE WW.
RECENT SURFACE ANALYSIS SHOWS A SWD SURGING OUTFLOW BOUNDARY
EXTENDING FROM 25 MI S BHM EXTENDING WSWWD TO 35 MI N OF JAN AND
DRAPING NWWD INTO SERN AR. AHEAD OF THIS FEATURE…SURFACE TEMPS
HAVE WARMED TO NEAR 90 UNDER MOSTLY CLEAR SKIES. DESPITE ONLY
MODEST MID-LEVEL LAPSE RATES DEPICTED ON 12Z JAN RAOB…VERY MOIST
PROFILE WITH LOWER TO MID 70S DEWPOINTS IS CONTRIBUTING TO 2000-3000
J/KG MLCAPE. WEAK SHEAR ACCORDING TO VWP DATA WILL LIKELY SUPPORT
ONLY PULSE-LIKE NATURE TO ANY TSTMS THAT DEVELOP AHEAD OF THE
BOUNDARY…WHEREAS SEMI-ORGANIZED SHORT MULTICELL LINE SEGMENTS WILL
PROBABLY BE MAINTAINED ALONG OR JUST BEHIND OUTFLOW BOUNDARY. MAIN
THREATS WITH THIS ACTIVITY WILL BE ISOLD DMGG WIND GUSTS WITH
PERHAPS MARGINALLY SEVERE HAIL POSSIBLE AS WELL.
..SMITH.. 07/16/2009
