May 22, 2010 1630 UTC Day 1 Convective Outlook
Updated: Sat May 22 16:27:25 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20100522 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20100522 1630 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20100522 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20100522 1630 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 221625
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1125 AM CDT SAT MAY 22 2010
   
   VALID 221630Z - 231200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
   MUCH OF THE DAKOTAS...PARTS OF NRN NEB AND THE PNHDL AND WRN MN...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS INTO THIS EVENING OVER PARTS OF
   THE CAROLINAS...
   
   ...SYNOPSIS...
   
   LARGE-SCALE TROUGH OVER THE WRN CONUS WILL BECOME INCREASINGLY
   ELONGATED IN NE-SW FASHION AS A STRONG SHORT WAVE TROUGH LIFTS
   NEWD...FORMING A CLOSED CIRCULATION OVER SASKATCHEWAN. 
   MEANWHILE...AN UPSTREAM JET STREAK WILL DIG SWD OVER THE ERN
   PACIFIC...SUPPORTING THE FORMATION OF A MORE SUBSTANTIAL UPPER LOW
   OVER CA/NV.  BETWEEN THESE EVOLVING FEATURES...SMALLER-AMPLITUDE
   PERTURBATIONS WILL TRANSLATE NEWD FROM THE GREAT BASIN INTO NRN
   PLAINS.  IN THE EAST...A MUCH WEAKER MIDLEVEL TROUGH WILL DRIFT EWD
   THROUGH THE LOWER GREAT LAKES AND MID ATLANTIC STATES.  
   
   ...NRN PLAINS LATE THIS AFTERNOON INTO TONIGHT...
   
   12Z OBSERVED SOUNDINGS INDICATE THE PRESENCE OF VERY STEEP MIDLEVEL
   LAPSE RATES AND A SUBSTANTIAL CAP IN ASSOCIATION WITH AN EML WHICH
   HAS OVERSPREAD THE GREAT PLAINS.  MEANWHILE...A 50+ KT LLJ CONTINUES
   TO TRANSPORT AN INCREASINGLY MOIST BOUNDARY LAYER NWD INTO THE
   REGION WITH DEW POINTS RISING THROUGH THE 60S ACROSS SYSTEM WARM
   SECTOR.  THIS MOISTURE INCREASE...COUPLED WITH DAYTIME HEATING AND
   THE STEEP LAPSE RATES WILL CONTRIBUTE TO AN EXTREMELY UNSTABLE AIR
   MASS BY AFTERNOON OVER CNTRL/ERN PARTS OF SD/NEB WHERE MLCAPE WILL
   APPROACH 4000 J/KG
   
   12Z MODEL GUIDANCE REMAINS CONSISTENT IN INDICATING THAT A COLD
   FRONT NOW EXTENDING FROM LOW PRESSURE OVER SERN MT SWWD INTO S-CNTRL
   WY WILL PROGRESS EWD INTO THE WRN DAKOTAS BY AFTERNOON.  ALONG THIS
   BOUNDARY...A SURFACE WAVE IS FORECAST TO DEVELOP OVER CNTRL SD WITH
   A DRY LINE EXTENDING SWD FROM THE TRIPLE POINT THROUGH THE NEB
   SANDHILLS INTO WRN KS.  THESE DATA SUGGEST THAT STORM INITIATION
   WILL BECOME INCREASINGLY LIKELY BY LATE AFTERNOON OR EARLY EVENING
   ALONG THE COLD FRONT AS THE WRN EDGE OF THE CAP IS ERODED BY A WEAK
   IMPULSE LIFTING NEWD THROUGH THE NRN HIGH PLAINS.
   
   FORECAST SOUNDINGS VALID 22/21Z-23/03Z AHEAD OF THE COLD FRONT OVER
   CNTRL SD SUGGEST THAT STORMS SHOULD BECOME RAPIDLY SEVERE WITH THE
   STRONG INSTABILITY...40-50 KT OF DEEP-LAYER SHEAR AND EFFECTIVE SRH
   OF 100-200 M2/S2.  VERY LARGE...DESTRUCTIVE HAIL APPEARS LIKELY AND
   TORNADOES WILL BE POSSIBLE WILL ANY SUPERCELLS THAT CAN MATURE AND
   REMAIN MORE DISCRETE.  STORMS SHOULD ORGANIZE INTO AN MCS WITH THE
   THREAT FOR MAINLY DAMAGING WINDS AND HAIL CONTINUING OVER PARTS OF
   THE ERN DAKOTAS INTO NWRN MN OVERNIGHT.
   
   ...CAROLINAS INTO THIS EVENING...
   
   SCATTERED DEEP CONVECTION IS ONGOING LATE THIS MORNING/EARLY
   AFTERNOON FROM PARTS OF THE CAROLINA PIEMONT SWWD INTO E-CNTRL GA IN
   CONJUNCTION WITH PASSAGE OF WEAK MIDLEVEL TROUGH AXIS.  AMBIENT AIR
   MASS IS RELATIVELY MOIST WITH DEW POINTS IN THE 60S.  AND WHILE
   MIDLEVEL LAPSE RATES ARE FORECAST TO REMAIN RATHER WEAK...STRONGER
   DAYTIME HEATING WITHIN CLOUD BREAKS SHOULD YIELD POCKETS OF MODERATE
   INSTABILITY WITH MLCAPE OF 1000-1500 J/KG.
   
   CURRENTLY IT/S NOT CLEAR WHETHER ONGOING CONVECTION WILL FURTHER
   DEEPEN INTO ROBUST TSTMS...OR WHETHER ADDITIONAL STORMS WILL FORM TO
   THE W OF THIS INITIAL ACTIVITY.  IN EITHER CASE...INCREASING DEEP
   NWLY SHEAR TO 30 KT AND THE MODERATE INSTABILITY SUGGEST SOME
   POTENTIAL FOR STORMS TO GROW UPSCALE INTO CLUSTERS WITH THE THREAT
   FOR DAMAGING WINDS AND HAIL INTO THIS EVENING.
   
   ..MEAD/HURLBUT.. 05/22/2010
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z