MESO: Mesoscale Discussion 0794

ACUS11 KWNS 121540
SWOMCD
SPC MCD 121539
ALZ000-MSZ000-LAZ000-121745-

MESOSCALE DISCUSSION 0794
NWS STORM PREDICTION CENTER NORMAN OK
1039 AM CDT SAT MAY 12 2012

AREAS AFFECTED...SERN LA...SRN MS...SWRN AL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 121539Z - 121745Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...STORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY
FROM LATE MORNING INTO THE AFTERNOON FROM SERN LA...SERN MS INTO
SWRN AL. THE MAIN THREAT WILL BE ISOLATED DAMAGING WIND. PLANS ARE
TO INCLUDE A LOW END SLIGHT RISK AREA TO ACCOUNT FOR THIS SCENARIO.
WW ISSUANCE WILL ULTIMATELY DEPEND ON CHARACTER AND ORGANIZATION OF
DEVELOPING STORMS.

DISCUSSION...LATE THIS MORNING A COUPLE OF CONVECTIVE INDUCED MCVS
WERE EMBEDDED WITHIN BASE OF LARGER SCALE UPPER TROUGH. ONE WAS
LOCATED OVER SWRN MS MOVING NEWD AND ANOTHER OVER SWRN LA MOVING
EAST. WEAK SFC MESO LOW WAS CENTERED OVER CNTRL LA WITH A WARM FRONT
EXTENDING EWD FROM THE LOW THROUGH SRN MS INTO SWRN AL. OUTFLOW
BOUNDARY EXTENDS SWD FROM THE LOW THROUGH SERN LA INTO THE NWRN
GULF. THE WARM SECTOR IS VERY MOIST WITH NEAR SFC DEWPOINTS IN THE
LOW 70S AND 1.6 INCH PW VALUES. AS THE BOUNDARY LAYER WARMS AND
TEMPERATURES RISE INTO THE LOW 80S...MODERATE INSTABILITY IS
EXPECTED...BUT MLCAPE SHOULD REMAIN GENERALLY AOB 1800 J/KG DUE TO
POOR MID LEVEL LAPSE RATES. WITH A WEAK CAP IN PLACE...STORMS ARE
EXPECTED TO CONTINUE DEVELOPING ALONG RESIDUAL OUTFLOW
BOUNDARIES...THE INLAND PROPAGATING SEA BREEZE...AS WELL AS NEAR THE
WARM FRONT.

BELT OF SLIGHTLY STRONGER FLOW ALONG SRN PERIPHERY OF UPPER LOW IS
CONTRIBUTING TO DEEP LAYER SHEAR FROM 30-35 KT OVER SRN LA INTO THE
BOOTHEEL OF MS AND SWRN AL. DEEP SHEAR IS WEAKER FARTHER TOWARD
CNTRL MS...BUT LOW LEVEL VEERING EXISTS NORTH OF THE WARM FRONT.
OVERALL ENVIRONMENT APPEARS FAVORABLE FOR MULTICELL AND MARGINAL
SUPERCELL STRUCTURES WITH A THREAT OF MAINLY ISOLATED DAMAGING WIND
AS LOW LEVEL LAPSE RATES STEEPEN AND PERHAPS A BRIEF TORNADO OR TWO.

..DIAL/HART.. 05/12/2012

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

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

LAT...LON 31519048 32428951 32388828 31618778 30618817 29768997
29379075 30109145 30999104 31519048

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