Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 230549
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1249 AM CDT SUN MAY 23 2010
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE CNTRL AND
   NRN PLAINS INTO THE UPPER MS VALLEY...
   
   ...SYNOPSIS...
   
   BLOCKING PATTERN WILL PERSIST SUNDAY WITH A LARGE UPPER TROUGH OVER
   THE WRN U.S. AND A RIDGE OVER MOST OF THE ERN HALF OF THE COUNTRY.
   CUTOFF UPPER LOW NEAR THE MID ATLANTIC WILL DRIFT SWD INTO THE
   CAROLINAS. THE SHORTWAVE TROUGH NOW MOVING INTO BASE OF THE BROAD
   WRN U.S. UPPER TROUGH WILL EJECT ENEWD THROUGH THE SWRN STATES TO
   NEAR THE 4 CORNERS AREA BY THE END OF THE PERIOD. COLD FRONT FROM
   ERN SD SWWD THROUGH CNTRL NEB AND CO WILL MOVE INTO UPPER MS VALLEY
   SWWD INTO THE CNTRL PLAINS. TRAILING PARTS OF THIS BOUNDARY WILL
   STALL ACROSS KS THEN LIFT NWD THROUGH NEB OVERNIGHT. DRYLINE WILL
   PERSIST FROM WRN TX NWD THROUGH WRN KS OR EXTREME ERN CO WHERE IT
   WILL INTERSECT THE FRONT.
   
   ...UPPER MS VALLEY... 
   
   A MOIST AND UNSTABLE WARM SECTOR WILL REMAIN FROM KS/NEB NEWD INTO
   THE UPPER MS VALLEY AREA WITH MLCAPE INCREASING TO 2000-3000 J/KG AS
   THE BOUNDARY LAYER WARMS. NRN BRANCH OF THE LOW LEVEL JET WILL LIFT
   NWD INTO ONTARIO IN ASSOCIATION WITH IMPULSE EJECTING INTO MANITOBA.
   THIS WILL RESULT IN ONLY MODEST CONVERGENCE ALONG MN PORTION OF COLD
   FRONT. MOREOVER...HEIGHTS WILL BEGIN TO RISE BY LATE AFTERNOON IN
   WAKE OF THE IMPULSE. DESPITE THE STRONG INSTABILITY...MODEST FORCING
   AND PRESENCE OF EML COULD LIMIT STORM COVERAGE AND SERVE AS A
   LIMITING FACTOR. NEVERTHELESS...A FEW STORMS MAY DEVELOP ALONG THE
   FRONT AS THE CAP WEAKENS AROUND PEAK HEATING. VERTICAL SHEAR WILL BE
   MARGINALLY SUPPORTIVE OF ORGANIZED STORMS WITH ISOLATED DAMAGING
   WIND AND LARGE HAIL THE MAIN THREATS.
   
   
   ...CNTRL AND NRN PLAINS AREA...
   
   AN UNSTABLE WARM SECTOR WILL EXIST SOUTH OF THE STALLED BOUNDARY
   ACROSS KS DURING THE AFTERNOON. HOWEVER...THE ATMOSPHERE WILL
   REMAINED CAPPED MOST OF THE DAY. BEST CHANCE FOR STORM INITIATION
   WILL LIKELY BE DURING THE LATE AFTERNOON OR EARLY EVENING WHEN THE
   STRENGTHENING LOW LEVEL JET WILL AUGMENT LIFT ALONG AND NORTH OF THE
   BOUNDARY ACROSS NWRN KS. INITIAL STORMS WILL LIKELY BE SUPERCELLS
   WITH A THREAT FOR LARGE HAIL AND A COUPLE OF TORNADOES.
   OVERNIGHT...THETA-E ADVECTION ALONG THE LOW LEVEL JET WILL PROMOTE
   NWD DESTABILIZATION...AND ADDITIONAL STORMS ARE EXPECTED TO DEVELOP
   INTO NEB AND SD. A STABILIZING BOUNDARY LAYER SUGGESTS STORMS WILL
   BECOME ELEVATED IN TIME WITH A THREAT FOR MAINLY LARGE HAIL.
   
   ...SRN PLAINS...
   
   PRESENCE OF CAPPING INVERSION AND WEAK FORCING MAY LIMIT STORM
   COVERAGE IN THIS REGION. HOWEVER...ISOLATED ACTIVITY MAY DEVELOP IN
   VICINITY OF THE DRYLINE AS WELL AS OVER THE HIGHER TERRAIN OF SWRN
   TX. WV IMAGERY INDICATES A SHORTWAVE TROUGH NEAR BAJA THAT COULD
   POTENTIALLY RESULT IN MORE STORM COVERAGE THAN CURRENTLY
   ANTICIPATED. VERTICAL SHEAR IS NOT EXPECTED TO BE PARTICULARLY
   STRONG...BUT THE SHEAR/INSTABILITY PARAMETER SPACE WILL SUPPORT
   STORMS WITH AT LEAST MARGINAL SUPERCELL STRUCTURES WITH ISOLATED
   LARGE HAIL AND DAMAGING WIND THE MAIN THREATS.
   
   ...CAROLINAS...
   
   A FEW STORMS ARE EXPECTED TO DEVELOP OVER THE CAROLINAS IN
   ASSOCIATION WITH SWD DRIFTING UPPER LOW. VERTICAL SHEAR OF 30-35 KT
   ALONG SRN PERIPHERY OF THIS FEATURE WILL SUPPORT MULTICELLS.
   ISOLATED STRONG WIND GUSTS AND HAIL WILL BE POSSIBLE THROUGH EARLY
   EVENING.
   
   ..DIAL.. 05/23/2010
   
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