MESO: Mesoscale Discussion 2150

ACUS11 KWNS 211825
SWOMCD
SPC MCD 211824
MSZ000-LAZ000-212030-

MESOSCALE DISCUSSION 2150
NWS STORM PREDICTION CENTER NORMAN OK
1224 PM CST WED NOV 21 2007

AREAS AFFECTED...ERN LA...CNTRL/SRN MS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 211824Z - 212030Z

A LOW PROBABILITY FOR ORGANIZED STORMS WITH DMGG WIND GUSTS...HAIL
AND ISOLD TORNADOES WILL EXIST ACROSS ERN LA INTO CNTRL/SRN MS THIS
AFTN. A WW IS NOT LIKELY...BUT MAY BE PSBL IF STORMS CONTINUE TO
INCREASE.

MORE SUBSTANTIAL BOUNDARY LAYER MOISTURE...CHARACTERIZED BY SFC DEW
POINTS IN THE MID-UPR 60S...WAS BEGINNING TO ADVECT NWD FROM ERN LA
INTO SRN MS AT EARLY AFTN. SFC ANALYSIS AND VSBL SATL LOOPS SHOWS
STREAMER CONFLUENCE BANDS BECOMING BETTER DEFINED...ONE FROM SCNTRL
LA NEWD INTO SWRN MS AND ANOTHER ONE FROM N OF NEW ORLEANS NEWD INTO
ECNTRL MS. TCU WERE SPROUTING INTO CB/S ALONG THESE ZONES...BEING
AIDED BY A SHEARING SUB-TROPICAL DISTURBANCE MOVING INTO THE LWR
SABINE RVR VLY.

H5 WINDS WITHIN THE SUBTROPICAL CONVEYOR WERE IN EXCESS OF 40 KTS
WITH RESULTANT BULK SHEAR SUFFICIENT TO SUPPORT BRIEF SUPERCELL
STRUCTURES. IN FACT...CELLS NW OF KBTR HAVE SHOWN SOME BROAD
ROTATION SINCE 1730Z. VWP FROM SLIDELL AND MOBILE INDICATE THAT THE
LOW-LEVEL FLOW WAS MODEST AT BEST...WITH LOW-LEVEL SHEAR ON THE WEAK
SIDE AT THE MOMENT. IN FACT...LATEST MODEL GUIDANCE SUGGESTS THAT
THE H85 FLOW WILL GRADUALLY VEER AS THE SHEARING VORT MAX MOVES
DOWNSTREAM...FURTHER LESSENING THE LOW-LEVEL SHEAR. SFC
CONVERGENCE...HOWEVER...WILL BE MAINTAINED ALONG THE BACKSIDE OF THE
ANTICYCLONIC FLOW TO THE EAST...AND OTHER STORMS MAY DEVELOP WITHIN
THE FAVORED LOW-LEVEL CONFLUENCE THROUGH THE AFTN. THUS...WHILE AN
ISOLD TORNADO CANNOT BE RULED OUT...PRIMARY SVR THREATS...IF
ANY...WILL BE DMGG WIND GUSTS OR PERHAPS HAIL.

.RACY.. 11/21/2007

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

ATTN...WFO...MOB...JAN...LIX...LCH...

30269239 30859218 33268962 33298856 31638874 30178864
29698985 29969118

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.