DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0117 AM CDT MON MAY 20 2013
   
   VALID 201200Z - 211200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF OK/FAR
   SOUTHEAST KS/SOUTHERN MO/NORTHWEST AR/FAR NORTH TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS TO THE
   MIDWEST/GREAT LAKES REGION...
   
   CORRECTED FOR AREAS IN MODERATE RISK HEADLINE
   
   ...SYNOPSIS...
   YET ANOTHER ACTIVE/RELATIVELY WIDESPREAD SEVERE WEATHER DAY IS
   LIKELY ACROSS PORTIONS OF THE SOUTHERN PLAINS TO MIDWEST TODAY AND
   TONIGHT. A PROMINENT CENTRAL CONUS UPPER TROUGH WILL CONTINUE A
   GENERAL EASTWARD ADVANCEMENT THROUGH TONIGHT...WITH A LEAD/CLOSED
   UPPER LOW PIVOTING OVER THE DAKOTAS/UPPER MIDWEST. A SOUTHERN STREAM
   SHORTWAVE TROUGH/MODERATELY STRONG POLAR JET WILL EJECT
   EAST-NORTHEASTWARD OVER THE SOUTHERN ROCKIES TO THE SOUTHERN
   PLAINS/OZARKS...WITH SEVERE TSTMS INCREASINGLY LIKELY BY PEAK
   HEATING AND CONTINUING INTO TONIGHT.
   
   MEANWHILE...A LINGERING UPPER LOW OVER THE COASTAL SOUTHEAST STATES
   WILL CONTRIBUTE TO ANOTHER DAY OF WIDELY SCATTERED TO SCATTERED
   TSTMS OVER THE REGION...SOME OF WHICH MAY AGAIN BE STRONG OR SEVERE.
   
   ...SOUTHERN PLAINS/OZARKS/MIDDLE MS VALLEY...
   UNDER THE INFLUENCE OF BROAD/MODERATELY STRONG CYCLONIC FLOW
   ALOFT...THE AIRMASS IS EXPECTED TO AGAIN BECOME QUITE UNSTABLE
   ACROSS MUCH OF THE REGION BY THE AFTERNOON BENEATH AN ELEVATED MIXED
   LAYER EXTENDING ACROSS THE SOUTHERN PLAINS INTO PARTS OF THE OZARKS
   AND LOWER/MIDDLE MS VALLEY. MIDDLE/UPPER 60S AND SOME LOWER 70S F
   SURFACE DEWPOINTS WILL BE QUITE COMMON WITHIN A SPATIALLY BROAD WARM
   SECTOR AHEAD OF A COLD FRONT EXTENDING FROM AN EASTERN DAKOTAS/MN
   SURFACE LOW SOUTHWESTWARD TO NEAR THE KANSAS CITY AREA/EASTERN KS
   AND WESTERN OK...AND AHEAD OF A DRYLINE EXTENDING FROM SOUTHWEST OK
   SOUTHWARD INTO WESTERN NORTH TX/WEST-CENTRAL TX. 
   
   OUTFLOW REMNANTS FROM OVERNIGHT/EARLY DAY CONVECTION ACROSS THE
   OZARKS/MIDDLE MS VALLEY WILL LIKELY BE A FACTOR INTO THIS
   AFTERNOON...POSSIBLY AS A RENEWED FOCUS FOR SEVERE TSTM
   REDEVELOPMENT...WITH THE MOST AGGRESSIVE HEATING/DESTABILIZATION ON
   THE WESTERN FRINGES OF THIS ACTIVITY ACROSS THE SOUTHERN PLAINS AND
   PERHAPS LOWER MO VALLEY JUST AHEAD OF THE TRUE SYNOPTIC COLD FRONT.
   SEVERE TSTMS CAPABLE OF HAIL/DAMAGING WINDS AND SOME TORNADO THREAT
   WILL BE POSSIBLE ALONG THIS FRONTAL ZONE ACROSS EASTERN KS/NORTHERN
   MO INTO THE UPPER MS VALLEY...WITH A PERSISTENT/EAST-NORTHEASTWARD
   DEVELOPING SEVERE THREAT INTO THE EVENING. 
   
   THAT SAID...THE MOST INTENSE/MOST PROBABLE SEVERE STORMS ARE
   ANTICIPATED A BIT FARTHER SOUTH-SOUTHWEST ACROSS THE SOUTHERN
   PLAINS/OZARKS BY MID/LATE AFTERNOON INTO TONIGHT. THIS INCLUDES A
   PORTION OF THE SYNOPTIC FRONT AND/OR OUTFLOW ACROSS FAR SOUTHEAST
   KS/SOUTHWEST MO...AREAS ROUGHLY PARALLEL AND NORTHWEST OF THE I-44
   CORRIDOR...BUT ESPECIALLY SOUTH-SOUTHWESTWARD INTO MUCH OF THE
   MIDDLE PART OF OK /POTENTIALLY INCLUDING OKC METRO/...TO NEAR THE
   HEAT-AIDED SURFACE LOW AND SOUTHWARD-EXTENDING SHARPENING DRYLINE
   INTO THE WESTERN PART OF NORTH TX/WEST-CENTRAL TX. IN THIS
   CORRIDOR...MLCAPE VALUES ARE LIKELY TO EXCEED 2500-3000 J/KG BY
   AFTERNOON WITHIN THE WARM SECTOR ACROSS OK AND
   WEST-CENTRAL/NORTH-CENTRAL TX...AND PERHAPS INTO PARTS OF SOUTHEAST
   KS AND MO. WITH BROAD/MODERATELY STRONG CYCLONIC MID-HIGH LEVEL FLOW
   /50+ KT AT 500 MB/ OVER THE REGION...40-50 KT OF EFFECTIVE SHEAR
   WILL COINCIDE WITH THE MAJORITY OF THE EFFECTIVE FRONTAL ZONE AND/OR
   DRYLINE ACROSS OK/EXTREME NORTH TX INTO SOUTHEAST KS AND THE OZARKS.
   
   THE DEGREE OF SHEAR AND MOISTURE/INSTABILITY WITHIN THE WARM SECTOR
   WILL FAVOR SCATTERED TO NUMEROUS SUPERCELL STRUCTURES...AT LEAST
   THROUGH MID-EVENING OF THE CONVECTIVE CYCLE. VERY LARGE HAIL AND
   TORNADOES ARE POSSIBLE WITH SUPERCELLS...WITH AN EARLY EVENING PEAK
   TORNADO THREAT /PERHAPS A COUPLE OF STRONG TORNADOES/ BOOSTED BY A
   NOCTURNALLY STRENGTHENING SOUTHERLY LOW LEVEL JET AND ASSOCIATED
   LOW-LEVEL HODOGRAPH ENLARGEMENT. ULTIMATELY...ONE OR MORE MCS/S
   SHOULD EVOLVE ALONG NOSE OF STRENGTHENING LOW LEVEL JET OVER OK AND
   EVENTUALLY INTO THE OZARKS BY LATE EVENING/OVERNIGHT. DAMAGING WIND
   POTENTIAL WILL LIKELY INCREASE IN ASSOCIATION WITH MCS DEVELOPMENT
   THIS EVENING....ASIDE FROM A SEVERE HAIL AND CONTINUED TORNADO
   RISK...BUT ON AN INCREASINGLY ISOLATED BASIS INTO LATE
   EVENING/OVERNIGHT.
   
   ...UPPER MIDWEST/GREAT LAKES...
   MID-LEVEL SHORTWAVE TROUGH/SPEED MAX WILL PIVOT NORTHEASTWARD OVER
   THE UPPER MIDWEST/UPPER MS VALLEY DURING THE AFTERNOON...WITH
   ASSOCIATED FORCING FOR ASCENT OVERSPREADING A RELATIVELY
   MOIST/UNSTABLE BOUNDARY LAYER TO THE SOUTH OF A WARM FRONT EXTENDING
   FROM THE EASTERN DAKOTAS/MN SURFACE LOW EASTWARD TO NORTHERN
   PORTIONS OF THE GREAT LAKES REGION. 
   
   TWO GENERAL SCENARIOS FOR SEVERE TSTM DEVELOPMENT SEEM PROBABLE THIS
   AFTERNOON. ONE BEING PARTS OF IA/UPPER MS VALLEY ON THE EASTERN
   PERIPHERY OF THE UPPER LOW AND UPPER JET EXIT REGION AS IT COINCIDES
   WITH THE SYNOPTIC FRONT. MEANWHILE...FARTHER EAST...PROPAGATION OF
   REMNANT OUTFLOW /EVEN SUBTLE REMNANTS INTO AFTERNOON/ ARE A
   PLAUSIBLE INFLUENCE FOR RENEWED TSTM DEVELOPMENT INTO A VERY
   UNSTABLE AIRMASS ACROSS THE GREAT LAKES REGION. OVERALL...THIS
   INCLUDES POTENTIAL FOR SOME SUPERCELLS ASIDE FROM SUSTAINED LINEAR
   STRUCTURES...WITH BOUTS OF DAMAGING WINDS/SEVERE HAIL AND A COUPLE
   OF TORNADOES ALL POSSIBLE ACROSS THE REGION.
   
   ...SOUTHEAST STATES/FL...
   THE AIRMASS SHOULD STRONGLY DESTABILIZE THIS AFTERNOON...ESPECIALLY
   IN AREAS NEAR AND WEST-SOUTHWEST OF THE APPALACHIANS SPINE...WITH
   DIURNALLY INCREASING/INTENSIFYING TSTM DEVELOPMENT FURTHER AIDED BY
   A PERSISTENT UPPER LOW OVER THE REGION. BOUTS OF DAMAGING WINDS AND
   SOME HAIL WILL BE POSSIBLE AS STORMS GENERALLY DRIFT SOUTHWARD
   THROUGH THE AFTERNOON/EARLY EVENING HOURS.
   
   ..GUYER/MEAD.. 05/20/2013