SPC AC 251255
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT WED MAY 25 2011
VALID 251300Z - 261200Z

Hail

Tor

Wind
...THERE IS A HIGH RISK OF SVR TSTMS OVER PARTS OF NORTHEAST
ARKANSAS...SOUTHEAST MISSOURI...SOUTHERN ILLINOIS...SOUTHWEST
INDIANA...WESTERN KENTUCKY...AND WESTERN TENNESSEE...
...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK
AREA...FROM PARTS OF THE LWR AND MID MS VLYS INTO THE LWR OH VLY... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ABOVE
AREAS...FROM SE TX NORTHEAST TO THE LWR GRT LKS... ...SVR WEATHER OUTBREAK EXPECTED FROM THE OZARKS AND MID/LWR MS VLY
INTO THE OH VLY TODAY THROUGH TONIGHT...
POTENT KS UPR LOW WILL CONTINUE EAST INTO WRN MO LATE TODAY...AND
INTO WRN IL EARLY THU...AS ASSOCIATED BELT OF 70+ KT MID LVL FLOW
SWEEPS E/NE FROM THE SRN PLNS/OZARKS INTO THE LWR MS/LWR TN VLYS.
AT THE SAME TIME...SFC LOW NOW OVER ERN KS SHOULD TRACK E INTO CNTRL
MO BY TNGT...AND INTO CNTRL IL EARLY THU. A SERIES OF CONFLUENCE
AXES/WEAK COLD FRONTS IN THE SRN QUADRANT OF THE LOW WILL MOVE
STEADILY E ACROSS THE OZARKS AND MID/LWR MS VLYS TODAY THROUGH EARLY
THU. E OF THE LOW...FRONT NOW EXTENDING EWD ACROSS CNTRL IL/IND
SHOULD ADVANCE N/NEWD AS A WARM FRONT INTO SRN MI AND THE LWR GRT
LKS.
...OZARKS INTO THE MID/LWR MS AND OH VLYS TODAY/TONIGHT...
STRONG SFC-BASED INSTABILITY WILL DEVELOP TODAY WITHIN DRY SLOT OF
SYSTEM UPR LOW AS THAT SYSTEM CONTINUES STEADILY EWD. BY EARLY TO
MID AFTN...SBCAPE SHOULD BE AOA 2500 J/KG OVER A BROAD CORRIDOR S OF
WARM FRONT FROM CNTRL IL/IND SWD INTO THE LWR MS... WITH HIGHER
VALUES POSSIBLE IN AXIS OF RICHEST BOUNDARY LAYER MOISTURE OVER THE
MS DELTA REGION OF AR/MS/TN.
SCTD TSTMS SHOULD FORM IN WEAKLY CAPPED ENVIRONMENT ON LEAD WIND
SHIFT/COLD FRONT OVER THE MO/AR OZARKS BY EARLY AFTN...WITH OTHER
STORMS LIKELY TO FORM AROUND THE SAME TIME OR PERHAPS A BIT LATER
ALONG LOW LVL CONFLUENCE AXIS EXTENDING FROM THE SRN IL SSW INTO SE
MO/ERN AR/WRN TN. ISOLD DEVELOPMENT ALSO MAY OCCUR LATE THIS AFTN
AND EVE SWWD ALONG COLD FRONT INTO SE TX AND LA.
STORM DEVELOPMENT FROM AR/TN NWD WILL BE AUGMENTED BY ASCENT/MID LVL
COOLING ASSOCIATED WITH VORT LOBE NOW ENTERING NW AR. AS THIS
FEATURE CONTINUES PIVOTING NEWD...ASSOCIATED BAND OF 50+ KT WSWLY TO
SWLY 700 MB FLOW WILL OVERSPREAD MUCH OF AR...SE MO...SRN
IL/IND...AND WRN PORTIONS OF KY/TN...ENHANCING CLOUD LAYER SHEAR.
AT THE SAME TIME...BROAD CURRENT OF SSWLY LOW LVL FLOW WILL PERSIST
AHEAD OF THE SFC LOW...MAINTAINING WIDESPREAD AREA WITH PW AOA 1.25
INCHES FROM THE WRN GULF CST WELL INTO THE OH VLY/LWR GRT LKS.
COMBINATION OF BROAD...MOISTURE-RICH...WEAKLY-CAPPED UNSTABLE
ENVIRONMENT WITH SUBSTANTIAL DEEP SHEAR SHOULD SUPPORT NUMEROUS
SUSTAINED SUPERCELLS WITH VERY LARGE HAIL AND HIGH WINDS. SOME OF
THE STORMS...ESPECIALLY THOSE ALONG IL/MO/AR CONFLUENCE BAND...COULD
YIELD STRONG/VIOLENT TORNADOES. STRONG TORNADOES ALSO MAY OCCUR
ALONG W/E WARM FRONT IN IL/IND. WIND PROFILES AND WEAKLY LINEAR LOW
LVL FORCING SUGGEST THAT THE ACTIVITY WILL EVOLVE INTO BROKEN LINE
SEGMENTS. EMBEDDED BOWING SEGMENTS/SUPERCELLS WITHIN THESE
STRUCTURES LIKELY WILL POSE A CONTINUED RISK FOR TORNADOES IN
ADDITION TO DMGG WIND/SVR HAIL INTO THE NIGHT. AN EXTENSIVE QLCS
MAY EVOLVE OVER PARTS OF THE OH AND TN VLYS BY EARLY THU AS THE BAND
OF STRONGEST...LARGELY UNIDIRECTIONAL DEEP SSWLY FLOW ON ERN SIDE OF
MO/IL UPR TROUGH APPROACHES THE WRN SLOPES OF THE APPALACHIANS.
..CORFIDI/SMITH.. 05/25/2011
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