May 19, 2011 1300 UTC Day 1 Convective Outlook
Updated: Thu May 19 12:41:04 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110519 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20110519 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
20110519 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
20110519 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 191237
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0737 AM CDT THU MAY 19 2011
   
   VALID 191300Z - 201200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM WEST CENTRAL TX INTO
   KS/NEB...
   
   ...CENTRAL/SOUTHERN PLAINS...
   THE WESTERN UPPER LOW CENTER WILL LIFT SLOWLY NORTHWARD DURING THIS
   FORECAST PERIOD...WHILE A 70-80 KNOT MID LEVEL JET MAX ROTATES
   AROUND THE LOW AND INTO THE CENTRAL HIGH PLAINS.  AMPLE LOW LEVEL
   MOISTURE IS ALREADY IN PLACE OVER THE SOUTHERN PLAINS...AND WILL
   ONLY INCREASE TODAY AS CONTINUED SOUTHERLY LOW LEVEL WINDS TRANSPORT
   MID 60S DEWPOINTS INTO SOUTHERN KS.  A WELL-DEFINED SURFACE DRYLINE
   IS EXPECTED TO BECOME ESTABLISHED BY MID AFTERNOON FROM
   SOUTH-CENTRAL KS INTO WESTERN OK...AND WILL BE THE PRIMARY FOCUS FOR
   SEVERE THUNDERSTORM POTENTIAL.
   
   CURRENT INDICATIONS ARE THAT THUNDERSTORMS WILL DEVELOP DURING THE
   MID AFTERNOON OVER NORTHWEST OK AND SOUTH-CENTRAL KS ALONG THE
   DRYLINE.  TEMPERATURES WELL INTO THE 80S AND DEWPOINTS IN THE MID
   60S WILL YIELD MLCAPE VALUES OF 2500-3000 J/KG AND VERY LITTLE CINH.
    A FEW DISCRETE SUPERCELLS APPEAR LIKELY WITH VERY LARGE HAIL AND
   TORNADOES POSSIBLE.  ACTIVITY SHOULD DEVELOP NORTH-NORTHEASTWARD
   INTO CENTRAL KS DURING THE EVENING WITH A CONTINUED RISK OF SEVERE
   STORMS.  STRENGTHENING LOW LEVEL WIND FIELDS DURING THE EARLY
   EVENING COULD RESULT IN A STRONG TORNADO OR TWO IN THIS AREA. 
   OVERNIGHT...STRONG STORMS PRODUCING HAIL MAY SPREAD AS FAR NORTH AS
   SOUTHERN NEB.  THE PRIMARY LIMITING FACTOR FOR A MORE WIDESPREAD
   SEVERE WEATHER EVENT WILL BE THE WEAK LARGE SCALE FORCING...WHICH
   MAY LIMIT THE NUMBER OF INTENSE STORMS THAT DEVELOP.
   
   THE POTENTIAL FOR THUNDERSTORM DEVELOPMENT SOUTHWARD ALONG THE
   DRYLINE OVER SOUTHWEST OK INTO NORTHWEST TX IS MORE CONDITIONAL. 
   HOWEVER...SEVERAL MODELS DO SHOW AT LEAST ISOLATED STORMS ALONG THIS
   CORRIDOR.  STORMS THAT CAN FORM SHOULD BE RESTRICTED TO THE NARROW
   AXIS IMMEDIATELY EAST OF THE DRYLINE...AND SHOULD WEAKEN RAPIDLY AS
   THEY MOVE AWAY FROM THE SOURCE OF CONVERGENCE AND INTO A MORE CAPPED
   ENVIRONMENT.  
   
   LATE TONIGHT...A STRONGER UPPER SHORTWAVE TROUGH WILL EJECT INTO TX.
    THIS IS EXPECTED TO RESULT IN MORE WIDESPREAD THUNDERSTORM ACTIVITY
   OVER WEST CENTRAL TX...MAINLY AFTER 06Z.  LARGE HAIL APPEARS LIKELY
   WITH THESE STORMS SO HAVE EXTENDED THE SLIGHT RISK SOUTHWARD.
   
   ...MID ATLANTIC STATES INTO SOUTHERN NEW ENGLAND...
   THE UPPER LOW CURRENTLY OVER THE UPPER OH VALLEY IS FORECAST TO MOVE
   EASTWARD AND INTO PA/NY BY FRIDAY MORNING.  SIMILAR TO THE PAST FEW
   DAYS...SUFFICIENT DEEP LAYER VERTICAL SHEAR IS PRESENT ACROSS THE
   MID ATLANTIC STATES AND SOUTHWEST NEW ENGLAND FOR SOME RISK OF
   ORGANIZED/ROTATING STORMS THIS AFTERNOON.  COOL TEMPERATURES ALOFT
   ASSOCIATED WITH THE UPPER LOW MAY ALSO RESULT IN HAIL IN THE
   STRONGEST CORES.  HOWEVER...THE OVERALL THREAT FOR SEVERE
   THUNDERSTORMS APPEARS RATHER MINIMAL SO WILL MAINTAIN ONLY 5%
   PROBABILITIES AT THIS TIME.
   
   ..HART/STOPPKOTTE.. 05/19/2011
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z