Categorical Graphic
Probabilistic Tornado 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
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
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 191958
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 PM CDT SUN JUN 19 2011
   
   VALID 192000Z - 201200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM NERN CO INTO NEB...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL PLAINS ESEWD
   ACROSS THE MIDDLE MS VALLEY INTO THE CAROLINAS...
   
   ...NERN CO INTO NEB...
   A LOW LEVEL BOUNDARY EXTENDS FROM NORTH CENTRAL NEB SWWD INTO NERN
   CO WHERE A DEN CYCLONE/VORTICITY ZONE IS EVIDENT FROM SURFACE DATA.
   TO THE SE OF THIS CONVERGENCE ZONE...MOIST SELY LOW LEVEL FLOW
   CONTINUES FROM NRN KS ACROSS NEB INTO NERN CO.  A SMALL CLUSTER OF
   STRONG/SEVERE STORMS HAS DEVELOPED NEAR THE BOUNDARY NEAR THE
   CO/NEB/WY BORDER INTERSECTION...AND ADDITIONAL CONVECTION IS LIKELY
   TO DEVELOP WITHIN THE NEXT SEVERAL HOURS NEAR THE SURFACE BOUNDARY. 
   SWLY WINDS ALOFT ARE EXPECTED TO GRADUALLY INCREASE INTO TONIGHT IN
   ADVANCE OF THE UPSTREAM UPPER LOW OVER THE GREAT BASIN...MAINTAINING
   STRONG VERTICAL SHEAR OVER THE REGION WHERE MODERATELY STEEP LAPSE
   RATES ARE ENHANCING INSTABILITY WITH MLCAPE OF 1500-2500 J/KG.  THIS
   WILL SUPPORT AN INCREASE IN SEVERE STORM POTENTIAL AS CONVECTION
   MOVES NEWD INTO THE PLAINS THIS EVENING WITH A THREAT FOR VERY LARGE
   HAIL...A FEW TORNADOES AND DAMAGING WIND GUSTS.  STORMS ARE EXPECTED
   TO GROW UPSCALE INTO ONE OR TWO BOWING MCS/S TONIGHT IN RESPONSE TO
   A STRENGTHENING NOCTURNAL LOW LEVEL JET...WITH THE PRIMARY SEVERE
   THREAT TRANSITIONING TO DAMAGING WIND GUSTS ALONG THE LEADING EDGE
   OF THE MCS OUTFLOW.
   
   ELSEWHERE...ONLY MINOR CHANGES HAVE BEEN MADE TO PREVIOUS OUTLOOK
   ...PRIMARILY TO ADJUST NRN EDGE OF SEVERE THREAT SWD OVER PARTS OF
   THE OH VALLEY IN THE WAKE OF THE MCV MOVING EWD OVER SWRN OH.
   
   ..WEISS.. 06/19/2011
   
   .PREV DISCUSSION... /ISSUED 1123 AM CDT SUN JUN 19 2011/
   
   ...SYNOPSIS...
   UNSEASONABLY STRONG TROUGH DIGGING SEWD ACROSS INTERMOUNTAIN REGION
   TO SRN ROCKIES BY TONIGHT. DOWNSTREAM ANOTHER MCV HAS DEVELOPED
   OVERNIGHT FROM MCS ACTIVITY AND CURRENTLY MOVING EWD OH VALLEY TO
   REACH THE MID ATLANTIC COAST LATER TONIGHT.
   
   SURFACE LOW WILL DEEPEN CENTRAL HIGH PLAINS THIS AFTERNOON/TONIGHT
   WITH APPROACHING STRONG UPPER TROUGH. E/W WARM FRONT CENTRAL PLAINS
   WILL SHIFT NWD TO VICINITY NEB/KS BORDER THIS AFTERNOON AND BE A
   PRIMARY FOCUS FOR THE EXPECTED SEVERE THUNDERSTORM OUTBREAK
   BEGINNING LATER THIS AFTERNOON AND TONIGHT.
   
   DRY LINE WILL AGAIN BECOME ACTIVE LATE THIS AFTERNOON FROM WRN OK
   INTO W CENTRAL TX WHERE VERY HOT/STEEP LAPSE RATES WILL RESIDE ALONG
   WITH MORE THAN SUFFICIENT INSTABILITY TO FUEL PULSE STORM
   DEVELOPMENT.
   
   ...CENTRAL PLAINS...
   ONLY ADJUSTMENTS TO THE MDT RISK WAS TO INCLUDE A LITTLE MORE OF
   NERN CO AS VEERING WIND PROFILES ON THE N SIDE OF DEEPENING SURFACE
   LOW ALONG WITH MLCAPES AOA 1500 J/KG FAVOR SUPERCELLS WITH VERY
   LARGE HAIL POTENTIAL.  ADDITIONALLY TORNADOES WILL BE POSSIBLE WITH
   ANY SUPERCELL THAT DEVELOPS.
   
   FURTHER E THE AIR MASS VICINITY E/W WARM FRONT BECOMES VERY UNSTABLE
   WITH MLCAPES RANGING UPWARDS TO 3-4000 J/KG ACROSS NRN KS/SRN NEB. 
   CAP WILL WEAKEN SUFFICIENTLY BY LATE AFTERNOON TO ALLOW RAPID
   DEVELOPMENT OF SEVERE THUNDERSTORMS INCLUDING SUPERCELLS.  ALONG
   WITH VERY LARGE HAIL...TORNADOES WILL BE POSSIBLE...PARTICULARLY
   ALONG AND JUST N OF WARM FRONT WHERE BACKED SURFACE FLOW WILL
   ENHANCE THE SHEAR.
   
   DURING THE EVENING...STORMS ARE LIKELY TO DEVELOP UPSCALE INTO A
   FORWARD PROPAGATING MCS ACROSS NEB. THIS ACTIVITY WOULD THEN SPREAD
   EASTWARD INTO PARTS OF IA/MO WITH A THREAT OF WIDESPREAD DAMAGING
   WINDS.
   
   ...LWR OH/TN VALLEYS INTO CAROLINAS...
   IMPRESSIVE MCV DEVELOPED OVERNIGHT AND CURRENTLY MOVING EWD ACROSS
   IND. A BAND OF STRONG WESTERLIES DEVELOPED S OF MCV AND WILL PROVIDE
   FAVORABLE SHEAR FOR REDEVELOPMENT OF SEVERE THUNDERSTORMS THIS
   AFTERNOON FROM TN VALLEY EWD TO MID ATLANTIC STATES BY TONIGHT.  AIR
   MASS CURRENTLY RECOVERING FROM W TO E ACROSS TN VALLEY IN THE WAKE
   OF MORNING MCS AND BY EARLY AFTERNOON WILL BECOME MDTLY UNSTABLE
   WITH MLCAPES AOA 2000 J/KG EWD ACROSS TN VALLEY AND SRN
   APPALACHIANS.
   
   THUNDERSTORMS WILL INCREASE RAPIDLY BY MID AFTERNOON AND FORM INTO
   LINE SEGMENTS/BOWS GIVEN THE 40-50KT OF WLY SHEAR ACROSS TN VALLEY. 
   WIND DAMAGE WILL BE THE PRIMARY THREAT AS STORMS CONTINUE TO DEVELOP
   UPSCALE AS THEY SPREAD EWD ACROSS TN VALLEY TO CAROLINAS. 
   ADDITIONAL SEVERE STORMS POSSIBLE BY MID AFTERNOON FURTHER S INTO
   NRN GA WHERE AIR MASS BECOMES MDTLY UNSTABLE WITH SOMEWHAT WEAKER
   SHEAR THAN FURTHER N.
   
   ...OK/TX...
   THE SURFACE DRYLINE IS EXPECTED TO EXTEND FROM WESTERN OK INTO WEST
   TX BY LATE AFTERNOON.  HOT SURFACE TEMPERATURES AND STEEP LOW LEVEL
   LAPSE RATES ALONG AND WEST OF THE DRYLINE...COUPLED WITH AFTERNOON
   MLCAPE VALUES OF 1500-2000 J/KG RANGE EAST OF THE DRYLINE...WILL
   PROMOTE ISOLATED THUNDERSTORM DEVELOPMENT.  THE STORMS THAT FORM
   WILL LIKELY REMAIN WITHIN A FEW COUNTIES OF INITIATION DUE TO
   INCREASING INHIBITION FARTHER EAST.  HOWEVER WITH NEAR DRY ADIABATIC
   LAPSE RATES TO 500MB...MLCAPES AOA 2000 J/KG AS WELL AS DCAPE TO
   ALMOST 2000 J/KG...STORMS THAT DO FORM WILL POSE A RISK OF DAMAGING
   WINDS AND HAIL.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z