MESO: Mesoscale Discussion 0585

ACUS11 KWNS 252136
SWOMCD
SPC MCD 252136
KYZ000-INZ000-ILZ000-MOZ000-252300-

MESOSCALE DISCUSSION 0585
NWS STORM PREDICTION CENTER NORMAN OK
0436 PM CDT WED APR 25 2012

AREAS AFFECTED...CNTRL IL AND SRN IL...SRN IND...WRN KY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 252136Z - 252300Z

STORMS ARE EXPECTED TO INCREASE IN COVERAGE OVER THE NEXT FEW
HOURS...WITH MAINLY A HAIL AND WIND THREAT. A WATCH APPEARS LIKELY.

THE 18Z ILX SOUNDING SHOWED STEEP LAPSE RATES ALOFT...BUT STILL
STABLE FOR SURFACE BASED PARCELS. HOWEVER...WHEN MODIFIED FOR
CURRENT CONDITIONS...TEMPERATURES IN THE LOWER 80S F AND DEWPOINTS
APPROACHING 60 F...CIN IS NEARLY GONE. INDEED...STORMS HAVE BEGUN TO
DEVELOP OVER CNTRL IL...NEAR STATIONARY BOUNDARY AND WHERE LOW LEVEL
WARM ADVECTION PERSISTS. THIS INITIAL ACTIVITY ALREADY APPEARS TO
HAVE A HAIL AND WIND THREAT.

WITH STEEP LAPSE RATES AND 50 KT NW ORIENTED DEEP SHEAR...THIS WILL
FAVOR LONG LIVED STORMS...INCLUDING SUPERCELLS AND/OR BOWS. STORM
MODE COULD REMAIN SUPERCELLULAR IF OUTFLOW PRODUCTION IS KEPT
LOW...BUT SOME SWWD PROPAGATION IS POSSIBLE...AND MERGING OUTFLOWS
WOULD RESULT IN MORE OF A WIND THREAT.

THE MAIN DETRIMENT TO TORNADOES WILL BE THE MARGINAL LOW LEVEL
MOISTURE IN RELATION TO RELATIVELY WARM/DRY AIR FROM 850-700 MB AND
MARGINAL LCL HEIGHTS. A ROGUE TORNADO CANNOT BE RULED OUT AS
ACTIVITY CONTINUES TO EVOLVE. THE AREA FROM SRN IL INTO SWRN
IND...NEAR THE BOUNDARY BE MONITORED CLOSELY FOR ANY TORNADO
POTENTIAL.

..JEWELL.. 04/25/2012

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

ATTN...WFO...LMK...IND...PAH...ILX...LSX...

LAT...LON 40428869 40028747 39048605 37858600 37048679 36768786
36858879 37378952 38039024 38369061 38999082 39789033
40428869

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