MESO: Mesoscale Discussion 0457

ACUS11 KWNS 111904
SWOMCD
SPC MCD 111904
INZ000-KYZ000-ILZ000-112030-

MESOSCALE DISCUSSION 0457
NWS STORM PREDICTION CENTER NORMAN OK
0204 PM CDT WED APR 11 2007

AREAS AFFECTED...E-CNTRL/SERN IL...W-CNTRL/SWRN IND...WRN KY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 111904Z - 112030Z

SEVERE WEATHER THREAT WILL INCREASE WITHIN RELATIVELY NARROW
INSTABILITY AXIS AS TSTM COVERAGE EXPANDS ALONG/AHEAD OF COLD FRONT.
WITH MODERATE DEEP LAYER SHEAR PROFILES...ESPECIALLY INVOF OF WARM
FRONTAL ZONE...THE POTENTIAL FOR LOW-TOPPED SUPERCELLS WILL EXIST
WITH MARGINALLY SEVERE HAIL AND GUSTY WINDS AS THE PRIMARY SEVERE
THREATS. AREA WILL BE MONITORED FOR A POSSIBLE WW.

AS OF 19Z...POWERFUL CYCLONE HAS LIFTED E/NEWD INTO W-CNTRL IL
AROUND 30 SE BRL. A COLD FRONT WAS DRAPED SWD...E OF THE MS
RIVER...WITH A WARM FRONT DRAPED EWD ACROSS CNTRL IL AND SRN IND.
FORCED ASCENT WITHIN LEFT EXIT REGION OF 90 KT 500 MB JET MAX
EMANATING NE OVER WRN TN/KY HAS LIKELY AIDED IN THE DEVELOPMENT OF
CONVECTION ACROSS CNTRL IL. ADDITIONAL TSTMS SHOULD BE SPAWNED
WITHIN THE NEXT HOUR OR SO AS VIS IMAGERY DEPICTS CU BECOME MORE
AGITATED SWD ALONG THE COLD FRONT. INSTABILITY REMAINS QUITE WEAK
/MLCAPES OF 250 TO 500 J/KG/ IN THE WARM SECTOR EVEN WITH PARTIAL
CLEARING OCCURRING AFTER WARM FRONT PASSAGE. DESPITE THIS LIMITING
FACTOR...DEEP-LAYER SHEAR WILL REMAIN FAVORABLE FOR ROTATING UPDRAFT
POTENTIAL. GIVEN RELATIVELY COLD MID/LOW-LEVEL TEMPERATURES...HAIL
SHOULD BE THE PRIMARY SEVERE THREAT. A LOCALIZED TORNADO THREAT MAY
DEVELOP INVOF THE NWD-MOVING WARM FRONT WHERE LOW-LEVEL FLOW REMAINS
SUFFICIENTLY BACKED. WITHIN THE WARM SECTOR...LOW-LEVEL WINDS HAVE
VEERED TO THE SW /PER REGIONAL VAD PROFILERS AND SURFACE OBS/.

.GRAMS.. 04/11/2007

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

ATTN...WFO...LMK...IND...PAH...LOT...ILX...

36828805 38498850 39458887 40228947 40668867 40268752
39298643 38428655 37098702

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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 chris@lib.siu.edu.