Apr 14, 2012 1300 UTC Day 1 Convective Outlook
Updated: Sat Apr 14 12:48:26 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Public Severe Weather Outlook

The SPC is forecasting ...an outbreak of severe thunderstorms and tornadoes is expected over parts of the central plains this afternoon and tonight....   Please read the latest public statement about this event.  View What is a Watch? clip.

Categorical Graphic
20120414 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120414 1300 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20120414 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20120414 1300 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
   SPC AC 141245
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0745 AM CDT SAT APR 14 2012
   
   VALID 141300Z - 151200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS LATER THIS AFTERNOON INTO
   TONIGHT FOR CENTRAL/ERN NEB...CENTRAL/ERN KS...AND CENTRAL/N CENTRAL
   OK...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK...FROM
   SW OK TO FAR NE NEB AND WRN IA...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK...FROM
   NW TX TO WRN NEB...IA...AND MO...
   
   ...TORNADO OUTBREAK EXPECTED LATE THIS AFTERNOON INTO TONIGHT FROM
   CENTRAL/ERN NEB SWD ACROSS KS TO CENTRAL OK...WITH THE POTENTIAL FOR
   LONG-TRACK/DAMAGING TORNADOES...
   
   ...SYNOPSIS...
   A CLOSED LOW OVER NW AZ THIS MORNING WILL PROGRESS EWD/ENEWD TO THE
   HIGH PLAINS BY THIS EVENING WHILE EVOLVING INTO MORE OF AN OPEN
   WAVE...AND THEN CONTINUE INTO THE CENTRAL PLAINS BY THE END OF THE
   PERIOD.  AN ASSOCIATED SURFACE CYCLONE WILL DEEPEN AND MOVE NEWD
   FROM ERN CO THIS AFTERNOON TO NE NEB/SE SD BY 12Z SUNDAY.  S OF THE
   CYCLONE...A WELL-DEFINED DRYLINE IS EXPECTED TO RESIDE FROM CENTRAL
   KS SWD INTO WRN OK AND NW TX BY THIS EVENING...WHILE A WARM FRONT
   MOVES NWD FROM KS THIS MORNING TO CENTRAL/ERN NEB BY LATE AFTERNOON.
    A MOIST AND UNSTABLE WARM SECTOR WILL COVER NEB/KS/OK/N TX TO THE E
   OF THE DRYLINE AND S OF THE WARM FRONT.  THE PRIMARY LOCATIONS FOR
   SEVERE STORM DEVELOPMENT TODAY WILL BE NEAR THE SURFACE LOW MOVING
   INTO NEB...AND THE DRYLINE TRAILING SWD INTO KS/OK.
   
   ...CENTRAL PLAINS THROUGH TONIGHT...
   THE FORECAST REASONING REMAINS LARGELY UNCHANGED FROM THE PAST FEW
   DAYS.  IN THE WAKE OF MORNING WAA STORMS ACROSS NE OK/SE KS/SW
   MO...LOW-LEVEL MOISTURE WILL SURGE NWD ACROSS KS TO S CENTRAL/SE NEB
   BY MID-LATE AFTERNOON.  DAYTIME HEATING INVOF THE DRYLINE AND
   BOUNDARY LAYER DEWPOINTS RANGING FROM THE LOW 60S IN NEB TO THE
   MID-UPPER 60S IN CENTRAL OK WILL CONTRIBUTE TO AFTERNOON MLCAPE
   VALUES OF 2000-3500 J/KG.  MEANWHILE... DEEP-LAYER VERTICAL SHEAR
   WILL BE QUITE SUPPORTIVE OF SUPERCELLS IN THE UNSTABLE WARM
   SECTOR...WITH EFFECTIVE BULK SHEAR OF 50-70 KT ACROSS ALMOST THE
   ENTIRE WARM SECTOR.  THE DEGREE OF LOW-LEVEL MOISTURE AND AN
   EXPECTED INCREASE IN LOW-LEVEL SHEAR LATER THIS AFTERNOON INTO EARLY
   TONIGHT WILL RESULT IN AN ENVIRONMENT CLEARLY INTO THE PARAMETER
   SPACE ASSOCIATED WITH PREVIOUS STRONG-VIOLENT AND LONG-TRACK TORNADO
   EPISODES.
   
   THE PRIMARY QUESTION THIS OUTLOOK WILL BE STORM COVERAGE ALONG THE
   DRYLINE THIS EVENING IN KS/OK.  THE CONVECTIVE SCHEMES IN THE
   OPERATIONAL MODELS VARY WITH STORM INITIATION SIGNALS...WHILE
   SEVERAL OF THE CONVECTION-ALLOWING MODELS GENERATE WIDELY SCATTERED
   DRYLINE SUPERCELLS IN THE 22-01Z TIME FRAME.  FORECAST
   SOUNDINGS...MODIFIED FOR EXPECTED AFTERNOON TEMPERATURES ALONG THE
   DRYLINE...SHOW DEEP MIXED LAYER AND LITTLE OR NO CONVECTIVE
   INHIBITION.  PLUS...A WELL-DEFINED BAND OF LOW-LEVEL ASCENT IS
   EXPECTED ALONG THE DRYLINE...WHICH SUGGESTS AT LEAST
   WIDELY-SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE KS/OK PORTION
   OF THE DRYLINE IS ENTIRELY PLAUSIBLE.  FARTHER N...POTENTIALLY MORE
   CONCENTRATED STORM DEVELOPMENT IS EXPECTED NEAR THE SURFACE LOW AND
   NW EDGE OF THE UNSTABLE WARM SECTOR IN NEB /WITHIN THE LEFT EXIT
   REGION OF THE JET ALOFT/.  ALL FACTORS FAVOR DISCRETE CONVECTIVE
   MODES THROUGH EARLY TONIGHT...AND THOUGH STORMS COULD BE WIDELY
   SPACED...THEY WILL BE CAPABLE OF PRODUCING LONG PATHS OF VERY LARGE
   HAIL AND DAMAGING TORNADOES THROUGH AT LEAST 06Z.
   
   LATE TONIGHT...THE MIDLEVEL TROUGH WILL FULLY EMERGE OVER THE PLAINS
   AND THE PACIFIC COLD FRONT WILL OVERTAKE THE DRYLINE...POTENTIALLY
   SUPPORTING MORE EXTENSIVE SQUALL LINE DEVELOPMENT NEAR OR AFTER 06Z.
    DAMAGING WINDS WILL BE MORE OF A THREAT WITH THE MORE LINEAR AND
   WIDESPREAD CONVECTION LATE TONIGHT...GIVEN A CONTINUATION OF
   SURFACE-BASED INSTABILITY AND 60-70 KT FLOW IN THE LOWEST FEW
   THOUSAND FEET AGL.
   
   ..THOMPSON/MOSIER.. 04/14/2012
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z