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

   SPC AC 190606
   
   DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0106 AM CDT WED MAY 19 2010
   
   VALID 191200Z - 201200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF OKLAHOMA AND
   ADJACENT PARTS OF NORTH TEXAS AND WESTERN ARKANSAS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM SOUTHWEST KANSAS TO
   NORTHERN TEXAS...PARTS OF SOUTHWEST ARKANSAS AND NORTHERN
   LOUISIANA...
   
   ADDED APPROXIMATE INITIATION TIME IN 4TH PARAGRAPH.
   
   ...SYNOPSIS...
   A POTENTIALLY SIGNIFICANT SEVERE WEATHER OUTBREAK APPEARS
   INCREASINGLY LIKELY ACROSS PARTS OF OKLAHOMA...SOUTHERN KANSAS...AND
   NORTHERN TEXAS LATER TODAY. STRONG TO SEVERE STORMS WILL ALSO BE
   POSSIBLE SOUTH AND EAST FROM THESE AREAS...FROM ARKANSAS TO
   LOUISIANA.
   
   ...SRN PLAINS INTO ARKLATEX...
   A LARGE DEEP-LAYER CYCLONE WILL EVOLVE ACROSS CO/WY EARLY TODAY AND
   THEN DRIFT EAST ACROSS THE CENTRAL PLAINS STATES THROUGH TONIGHT.
   WIDESPREAD THUNDERSTORMS WERE ALREADY OCCURRING AHEAD OF THIS
   DEVELOPING LOW AS WARM ADVECTION AND LARGE SCALE ASCENT ACT ON A
   MOIST AND MODERATELY UNSTABLE AIR MASS FROM TX TO KS. PRECIPITATION
   AND RESIDUAL CLOUDINESS FROM THE STORMS NOW DEVELOPING ACROSS NRN OK
   AND KS WILL ACT TO ESTABLISH A NW-SE ORIENTED WARM FRONT ACROSS OK
   LATER THIS MORNING.
   
   AS THE UPPER LOW EMERGES OVER WRN KS LATER THIS AFTERNOON... TRIPLE
   POINT SURFACE LOW IS FORECAST TO STRENGTHEN INVOF OK PANHANDLE AS
   DRYLINE SHARPENS AND SPREADS EAST FROM ERN TX PANHANDLE. BELT OF
   40-50KT WLY CYCLONIC MID LEVEL FLOW ATOP SLY/SELY LOW LEVEL FLOW
   ACROSS THE WARM SECTOR WILL CONTRIBUTE TO STRONG EFFECTIVE SHEAR AOA
   40KT. DIURNAL HEATING AND GRADUAL MOISTENING OF THE BOUNDARY LAYER
   SHOULD RESULT IN AN INCREASINGLY UNSTABLE WARM SECTOR WITH WEAKLY
   CAPPED MLCAPE OF 1500-2000 J PER KG BY AFTERNOON.
   
   GIVEN WEAK INHIBITION AND PERSISTENT MODEST FORCING FOR ASCENT
   EXPECT WARM SECTOR STORM INITIATION BY 21Z. DISCRETE SUPERCELLS
   SHOULD EVOLVE QUICKLY AHEAD OF THE DRY LINE IN WRN OK...WITH
   ADDITIONAL STORMS POSSIBLE NEAR/ALONG RESIDUAL OUTFLOWS AND NEAR
   SURFACE WARM FRONT...FROM NRN/CNTRL OK TO NRN TX/AR/LA. EFFECTIVE
   HELICITY IN THE RANGE OF 200-300 M2/S2...AND RELATIVELY HIGH
   BOUNDARY LAYER RH/LOW LFC ACROSS CNTRL OK...SHOULD RESULT IN AN
   ENHANCED STRONG TORNADO POTENTIAL ACROSS THIS AREA FROM LATE
   AFTERNOON INTO EARLY EVENING.
   
   UNLIKE MAY 10...WEAKER FLOW REGIME RESULTS IN SLOWER STORM/BUNKERS
   CELL MOTION OF ENE AROUND 25 KT...AS OPPOSED TO ENE AT 50KT.
   FURTHERMORE...INSTABILITY APPEARS A BIT WEAKER. NONETHELESS...A
   POTENTIALLY VOLATILE STRONG TORNADO SITUATION MAY EVOLVE ACROSS
   PORTIONS OF CNTRL OK DURING THE AFTERNOON...POSSIBLY MOVING TOWARD
   ERN OK INTO THE EVENING. THIS IS A RELATIVELY LIMITED GEOGRAPHIC
   AREA OF GREATER TORNADO POTENTIAL. COMBINED WITH THE POSSIBILITY
   THAT FORECAST CERTAINTY CAN INCREASE WITH THE LIGHT OF DAY...GREATER
   TORNADO PROBABILITIES...AND AN UPGRADE TO HIGH RISK...MAY OCCUR IN
   SUBSEQUENT OUTLOOKS.
   
   IN ADDITION TO THE TORNADO POTENTIAL...VERY LARGE HAIL AND LOCALLY
   DAMAGING DOWNBURST/OUTFLOW WINDS WILL ACCOMPANY STORM DEVELOPMENT
   ACROSS A LARGER AREA FROM SRN KS EXTENDING INTO TX...AR AND LA FROM
   AFTERNOON THROUGH THE EVENING.
   
   AS CONVECTION CONGEALS OVER ERN OK THROUGH THE EVENING...LIFT AND
   SUSTAINED INSTABILITY ACROSS THE WARM FRONT...AND UPSCALE EVOLUTION
   IN STRONGLY SHEARED FLOW...WILL CONTRIBUTE TO FORWARD PROPAGATING
   MCS/SQUALL LINE WITH DAMAGING WINDS SPREADING SEWD TOWARD AR AND THE
   ARKLATEX THROUGH THURSDAY MORNING.
   
   ...ERN NC...
   GREATER LOW LEVEL MOISTURE ALONG A RESIDUAL FRONTAL SEGMENT ACROSS
   SERN NC...COUPLED WITH DIURNAL HEATING...SHOULD CONTRIBUTE TO
   MODERATE INSTABILITY LATER TODAY. STRENGTHENING MID LEVEL WLY FLOW
   AROUND 40KT AND DPVA ASSOCIATED WITH PASSAGE OF SHORT WAVE TROUGH TO
   THE NORTH MAY BE SUFFICIENT FOR A FEW VIGOROUS STORMS ACROSS THE
   IMMEDIATE COASTAL ZONE. A COUPLE HAIL/WIND EVENTS APPEAR POSSIBLE
   WITH THIS ACTIVITY.
   
   ..CARBIN.. 05/19/2010
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z