May 30, 2013 0600 UTC Day 2 Convective Outlook
Updated: Thu May 30 06:04:36 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130530 0600 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20130530 0600 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 341,448 44,547,120 Chicago, IL...Indianapolis, IN...Oklahoma City, OK...Kansas City, MO...Tulsa, OK...
   SPC AC 300557

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1257 AM CDT THU MAY 30 2013

   VALID 311200Z - 011200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FOR OK AND ERN KS NEWD INTO THE
   SRN GREAT LAKES...

   ...SYNOPSIS...
   A DEEP-LAYER CYCLONE WILL REMAIN OVER THE UPPER MIDWEST THROUGH
   SATURDAY MORNING WHILE A BELT OF STRONG CYCLONIC FLOW WILL ARC
   THROUGH THE BASE OF THE MID-UPPER TROUGH OVER THE CNTRL PLAINS NEWD
   INTO THE GREAT LAKES.  IN THE LOW LEVELS...AN OCCLUDED LOW/FRONT
   WILL DRAPE ITSELF OVER THE UPPER MS RIVER VALLEY WITH A COLD FRONT
   EXTENDING SWWD INTO THE CNTRL PLAINS WHERE A SECONDARY LEE CYCLONE
   OVER THE TX PANHANDLE WILL REMAIN QUASI-STATIONARY DURING THE DAY. 
   A DRYLINE LINE WILL EXTEND SWD FROM WRN OK INTO TX.  

   ...OK/KS AND OZARKS...
   HIGH QUALITY BOUNDARY LAYER MOISTURE --CHARACTERIZED BY 16 G/KG
   LOWEST 100 MB MEAN MIXING RATIO-- SAMPLED OVER THE TX COASTAL PLAIN
   ON WEDNESDAY EVENING WILL CONTINUE TO BE DRAWN NWD INTO MUCH OF
   OK...BENEATH A REINVIGORATED EML FORECAST TO OVERSPREAD OK/SRN KS
   DURING THE DAYTIME HOURS FRIDAY.  DESPITE PROBABLE THURSDAY
   NIGHT/FRIDAY MORNING STORMS OVER A PORTION OF THIS REGION...A
   RELOADING OF STEEP MID LEVEL LAPSE RATES /IN EXCESS OF 8 DEG C PER
   KM H7-H5/ OVER THIS REGION FROM THE W IS LIKELY.  ALTHOUGH THE
   DETAILS TO PRIOR STORM ACTIVITY ARE UNCERTAIN BOTH IN TERMS OF THE
   EXTENSIVENESS OF CONVECTIVE OVERTURNING AND PLACEMENT OF OUTFLOW
   BOUNDARIES...STRONG SURFACE HEATING SHOULD OCCUR IN ITS WAKE OVER
   AREAS TO THE S AND SW.  

   A WEAKLY CAPPED AND VERY TO EXTREMELY UNSTABLE BOUNDARY LAYER IS
   FORECAST BY MID-LATE AFTERNOON OVER OK WITH MLCAPE RANGING FROM
   3000-4500 J/KG...WITH DESTABILIZATION NOT QUITE AS STRONG FARTHER NE
   OVER WRN MO/SERN KS WHERE SOME AIRMASS RECOVERY IS FORECAST TO
   OCCUR.  THE ORIENTATION OF THE N-S DRYLINE OVER OK/SRN KS NORMAL TO
   STRONG MID-HIGH LEVEL FLOW /NEUTRAL MID LEVEL HEIGHT FIELD/ WILL
   SUPPORT EXPLOSIVE DISCRETE SUPERCELL DEVELOPMENT GIVEN THE MAGNITUDE
   OF EXPECTED DEEP SHEAR/BUOYANCY.  A LARGE TO PERHAPS EXTREMELY LARGE
   HAIL THREAT MAY DEVELOP WITH ANY INTENSE SUPERCELLS.  MODELS DIFFER
   REGARDING THE LOW LEVEL MASS RESPONSE OVER OK/KS DURING THE
   AFTERNOON/EVENING...WHICH WILL HAVE AN INFLUENCE ON LOW LEVEL SHEAR
   AND TORNADO POTENTIAL/INTENSITY.  SOME FORECAST SOUNDINGS SHOW A
   RATHER IMPRESSIVE INCREASE IN LOW LEVEL HODOGRAPH SIZE DURING THE
   AFTERNOON-EARLY EVENING PERIOD...WHILE OTHER FORECAST SOUNDINGS ARE
   MUTED IN THIS LOW LEVEL SHEAR DEPICTION.  REGARDLESS...A LARGE
   HAIL/DMGG WIND/TORNADO THREAT WILL EXIST WITH SUPERCELLS THAT
   DEVELOP OVER THIS REGION.

   ATTM...WILL REFRAIN FROM A HIGHER CATEGORICAL RISK BUT ACKNOWLEDGE
   AN UPGRADE MAY BE REQUIRED IN LATER OUTLOOKS...ESPECIALLY FOR A
   PORTION OF OK.

   LATER IN THE EVENING...A STRENGTHENING SLY LLJ AND SWD ACCELERATING
   COLD FRONT OVER KS/NRN OK WILL LIKELY LEAD TO GREATER STORM
   COVERAGE...POSING A SEVERE THREAT WELL INTO THE EVENING/OVERNIGHT
   HOURS AS STORMS GROW UPSCALE FROM OK ENEWD INTO THE OZARKS.

   ...MO NEWD INTO THE GREAT LAKES...
   SEVERAL ROUNDS OF STORMS ARE POSSIBLE OVER THE LOWER MO RIVER VALLEY
   OWING TO BOTH LINGERING STORM ACTIVITY FROM THE MORNING AND
   DIURNALLY-DRIVEN STORMS LATER IN THE DAY ALONG THE FRONT.  MODELS
   ARE IN FAIRLY GOOD AGREEMENT IN SHOWING A MOIST/MODERATELY UNSTABLE
   AIRMASS DEVELOPING OVER A LARGE PART OF THIS REGION WITH SCATTERED
   TO NUMEROUS STORMS EXPECTED TO DEVELOP.  THE MAIN BELT OF STRONGER
   1-3 KM SWLY FLOW WILL RESIDE OVER THIS REGION...ACTING TO SUPPORT
   ORGANIZED CLUSTERS OF STRONG-SEVERE STORMS IN THE FORM OF SUPERCELLS
   AND BOWING LINE SEGMENTS.  IF SUBSTANTIAL DESTABILIZATION CAN
   OCCUR...STRONG FLOW FIELDS WOULD SUPPORT AN APPRECIABLE TORNADO
   THREAT --IN ADDITION TO HAIL/WIND-- AND PERHAPS HIGHER SEVERE
   PROBABILITIES THAN CURRENTLY FORECAST FOR A PORTION OF THIS AREA. 
   EVENTUAL STORM MERGERS/CONSOLIDATION BY EVENING WOULD FAVOR THE
   GRADUAL TRANSITION TO MORE OF A STRAIGHT-LINE WIND THREAT THAT MAY
   PERSIST INTO SATURDAY MORNING.

   ..SMITH.. 05/30/2013

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