[MCD] SWOMCD

Sun Apr 16 18:21:05 UTC 2006

ACUS11 KWNS 161819
SWOMCD
SPC MCD 161818 
ILZ000-MOZ000-IAZ000-WIZ000-161915-

MESOSCALE DISCUSSION 0526
NWS STORM PREDICTION CENTER NORMAN OK
0118 PM CDT SUN APR 16 2006

AREAS AFFECTED...SERN IA...NERN MO...WRN IL

CONCERNING...TORNADO WATCH 193...

VALID 161818Z - 161915Z

SEVERE STORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY
INSIDE OF TORNADO WATCH 193 OVER THE NEXT HOUR.

LATEST ANALYSIS PLACES OCCLUDED LOW OVER SCNTRL IA WITH WARM FRONT
EXTENDING EAST INTO NRN IL AND WIND SHIFT/CONFLUENCE AXIS DEVELOPING
EAST INTO WRN IL. STRONGLY DIFFLUENT MID LEVEL FLOW AHEAD OF THE
DEEP LAYER CYCLONE WAS ACTING ON DESTABILIZING WARM SECTOR AIR MASS
FROM SERN IA ACROSS CNTRL IL AND SUPPORTING INCREASING TSTM
DEVELOPMENT OVER THESE AREAS. DEEP LAYER SHEAR OF 40-50KT ACROSS IL
PORTIONS OF THE WATCH IS MORE THAN ADEQUATE FOR SUPERCELLS AND
EXPECT STORMS NOW DEVELOPING ACROSS CNTRL IL TO REACH SEVERE LEVELS
SHORTLY. LARGE HAIL APPEARS TO BE THE MAIN THREAT FROM THIS
CONVECTION. HOWEVER...STORMS NEAR OR CROSSING THE WARM FRONT...FROM
GBG TO PIA...WILL NEED TO BE MONITORED FOR LOW LEVEL ROTATION AND
POSSIBLE TORNADO THREAT GIVEN EFFECTIVE HELICITY VALUES 150-200
MS/S2 BASED ON CELL WSW MOTION AT 25KT.

STORMS NEAR THE LOW AND EAST TO DVN AREA WERE DEVELOPING IN A WEAKER
SHEAR ENVIRONMENT DUE TO WEAKER FLOW NEAR THE LOW CENTER. THIS IS
FURTHER SUPPORTED BY LATEST DVN SOUNDING. HOWEVER...DVN SOUNDING
ALSO DEPICTS SUFFICIENT LOW LEVEL CAPE FOR MODEST UPDRAFT
STRETCHING. GIVEN STRONG BACKGROUND VORTICITY IN VICINITY OF THE
LOW...A FEW OF THESE CELLS COULD ACQUIRE ROTATION AND POSE A HAIL
AND BRIEF TORNADO THREAT INTO THIS AFTERNOON.

..CARBIN.. 04/16/2006

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

ATTN...WFO...PAH...LOT...ILX...LSX...DVN...ARX...DMX...EAX...

42609347 42629064 40488850 38418828 38169132 40539246
40569349 42149407 42189356 

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