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 261958
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 PM CDT SUN JUN 26 2011
   
   VALID 262000Z - 271200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN PLAINS REGION SEWD
   INTO THE SOUTHEAST CONUS...
   
   ...NRN PLAINS/MID MO VALLEY REGION AND VICINITY...
   SCENARIO REMAINS HIGHLY UNCERTAIN ATTM ACROSS THE REGION...WITH MOST
   SUBSTANTIAL CONVECTION REMAINING FOCUSED OVER N CENTRAL NEB WHERE A
   COUPLE OF HP-TYPE SUPERCELL STORMS HAVE CONTINUED TO EVOLVE.  THIS
   REGION REMAINS N OF THE NRN KS WARM FRONT...WITH LOW CLOUDS
   WIDESPREAD ACROSS NEB BENEATH SUBSTANTIAL CAP -- WHICH REMAINED
   QUITE STOUT AND EVEN INCREASED PER AREA 18Z RAOBS.  THE CAPPING IS A
   CONCERN...AS MODELS -- AND THE GOING SPC FORECAST -- INDICATING
   WIDESPREAD/SIGNIFICANT SEVERE POTENTIAL WITHIN THIS STILL-STABLE
   LOW-LEVEL ENVIRONMENT.  
   
   GIVEN THESE ISSUES AND ASSOCIATED UNCERTAINTY...AND OVERALL
   EXPECTATION OF A SOMEWHAT LESS SIGNIFICANT TORNADO THREAT THAN
   EARLIER FORECAST...WILL REMOVE MODERATE RISK FORECAST ATTM.  MOST
   LIKELY SCENARIO ATTM APPEARS TO BE THAT STORMS OVER N CENTRAL NEB
   EVENTUALLY EVOLVE INTO A MORE LINEAR/BOWING MCS...WHICH SHOULD
   ATTEMPT TO MOVE SEWD INTO THE MORE CAPPED AIRMASS.  THUS...THOUGH
   UNCERTAIN -- WILL MAINTAIN HIGHER PROBABILITY SEVERE FORECAST -- TO
   INCLUDE POTENTIAL FOR DAMAGING WINDS...LARGE HAIL...AND A FEW
   TORNADOES -- FROM ERN SD/N CENTRAL NEB SEWD ACROSS THE MID MO VALLEY
   REGION.  
   
   ...MO INTO THE MID SOUTH/SOUTHEAST...
   CLUSTER OF STORMS CONTINUES MOVING ACROSS MIDDLE TN/NRN AL...WITH
   STORMS ALSO INCREASING ON THE PERIPHERY OF THIS CLUSTER. 
   WELL-ORGANIZED CIRCULATION EXISTS WITH THIS MCS...ALONG WITH A VERY
   UNSTABLE AIRMASS NEAR AND S OF THE STORMS INTO MS/AL. 
   THEREFORE...WILL MAINTAIN SLIGHT RISK INTO THE CENTRAL GULF COAST
   REGION AHEAD OF THIS CLUSTER.  
   
   FARTHER W/NW...STORMS ARE DEVELOPING IN A VERY UNSTABLE AIRMASS
   ACROSS SERN MO...WHERE FAVORABLY-VEERING FLOW WITH HEIGHT IS ALSO
   INDICATED.  WITH AN INCREASE IN CONVECTIVE COVERAGE AN INTENSITY
   EXPECTED...HAVE EXPANDED MORE SUBSTANTIAL SEVERE WEATHER PROBABILITY
   INTO THIS REGION FOR THIS AFTERNOON/EARLY EVENING.
   
   ..GOSS.. 06/26/2011
   
   .PREV DISCUSSION... /ISSUED 1125 AM CDT SUN JUN 26 2011/
   
   ...NRN/CNTRL PLAINS INTO UPPER MS VALLEY...
   
   VORTICITY MAXIMUM AND ASSOCIATED 40-50 KT+ MIDLEVEL JET STREAK OVER
   THE NRN INTERMOUNTAIN REGION WILL TRANSLATE EWD INTO THE DAKOTAS BY
   27/12Z...RESULTING IN A CORRIDOR OF 30M/12-HR HEIGHT FALLS AT 500 MB
   OVERSPREADING REGION DURING THE LATTER HALF OF THE PERIOD.  IN THE
   LOW LEVELS...COLD FRONT FROM CNTRL ND TO LOW PRESSURE AREA OVER NWRN
   NEB WILL PROGRESS SEWD THROUGH THE DAKOTAS AND MOST OF NEB BY THE
   END OF THE D1 PERIOD.  AT THE SAME TIME...WARM FRONT ANALYZED FROM
   THERMAL LOW OVER SWRN KS NEWD THROUGH E-CNTRL KS AND CNTRL MO WILL
   LIFT NWD TOWARD THE MID MO VALLEY WITH THE HIGHEST CONCENTRATION OF
   SEVERE WEATHER EXPECTED LATER TODAY INTO TONIGHT TO THE N OF THIS
   BOUNDARY...AND S/SE OF ADVANCING COLD FRONT.
   
   TSTMS ARE ONGOING ACROSS PORTIONS OF THE DAKOTAS INTO NWRN NEB ALONG
   THE NRN EDGE OF THE STRONGER CAPPING AND IN ADVANCE OF LEAD
   SHORTWAVE TROUGH LIFTING NEWD THROUGH ERN PARTS OF MT/WY.  FORCING
   FOR ASCENT ATTENDANT TO THIS IMPULSE SHOULD SUSTAIN TSTM ACTIVITY
   TODAY INVOF THE COLD FRONT OVER THE DAKOTAS INTO NWRN/N-CNTRL NEB
   WHERE THE CAP IS WEAKER.  CURRENT VISIBLE SATELLITE SUGGESTS THAT
   POCKETS OF STRONGER DIABATIC HEATING WILL OCCUR ACROSS N-CNTRL NEB
   INTO SRN SD WHERE MLCAPE VALUES WILL INCREASE TO 1500-2500 J/KG. 
   CURRENT OBSERVATIONAL DATA AND MODEL FORECASTS INDICATE LOW-LEVEL
   ELY/SELY FLOW WILL BE MAINTAINED BENEATH 40-50 KT WINDS IN THE
   MIDLEVELS RESULTING IN PRONOUNCED VEERING WITH HEIGHT AND MORE THAN
   SUFFICIENT VERTICAL SHEAR FOR ORGANIZED STORM STRUCTURES.
   
   THE PRIMARY UNCERTAINTY LIES IN THE DOMINANT CONVECTIVE MODE /AND
   ATTENDANT SEVERE WEATHER HAZARDS/ OWING TO THE EARLY STORM FORMATION
   AND POTENTIAL FOR MORE WIDESPREAD COLD POOL DEVELOPMENT.  GIVEN THE
   CO-LOCATION OF RICH BOUNDARY LAYER MOISTURE...STEEP MIDLEVEL LAPSE
   RATES AND RELATIVELY STRONG VERTICAL SHEAR...THE POTENTIAL WILL
   EXIST FOR SUPERCELLS AND BOWING STRUCTURES CAPABLE OF
   TORNADOES...DAMAGING WINDS AND HAIL.  FOR ADDITIONAL NEAR-TERM
   GUIDANCE ON THIS AREA SEE MCD 1398.
   
   FARTHER E/SE ACROSS THE MODERATE RISK AREA...SCENARIO IS COMPLICATED
   BY A POTENTIALLY STRENGTHENING CAP TODAY AND LINGERING CLOUDS N OF
   WARM FRONT LIFTING NWD THROUGH KS/MO.  IT DOES APPEAR THAT EVOLVING
   TSTM REGIME MENTIONED ABOVE WILL BEGIN TO IMPACT PORTIONS OF THE MID
   MO VALLEY AREA LATER THIS AFTERNOON BEFORE PROGRESSIVELY
   OVERSPREADING REGION TONIGHT.  ADDITIONAL IN SITU STORM DEVELOPMENT
   WILL BE POSSIBLE ALONG THE WARM FRONT LIFTING NWD WHERE LOCAL
   ENVIRONMENT WILL BE QUITE FAVORABLE FOR TORNADIC SUPERCELLS GIVEN
   MLCAPE OF 2500-4000 J/KG...EFFECTIVE SRH OF 200-400 M2/S2 AND
   EFFECTIVE BULK SHEAR OF 45-60+ KT. THOUGH CONDITIONAL ON STORM
   FORMATION/SUSTENANCE...SETUP WILL BE QUITE SUPPORTIVE OF INTENSE
   SUPERCELLS CAPABLE OF TORNADOES /SOME STRONG/...VERY LARGE HAIL AND
   DAMAGING WINDS.
   
   ...LOWER MO VALLEY/OZARKS INTO MID SOUTH...
   
   A CLUSTER OF ELEVATED TSTMS HAS DEVELOPED THIS MORNING ACROSS SERN
   KS INTO SWRN MO WITHIN A ZONE OF LOW-LEVEL WAA/ISENTROPIC ASCENT
   ALONG THE ERN EDGE OF THE STRONGER CAP /REF. 12Z LMN SOUNDING/. 
   GIVEN THE LARGE-SCALE AIRFLOW REGIME FORECAST...THE CAP SHOULD
   CONTINUE TO STRENGTHEN FROM W-E ACROSS REGION TODAY.  AS
   SUCH...SEVERE WEATHER POTENTIAL REMAINS SOMEWHAT UNCERTAIN. 
   HOWEVER...SHOULD ONGOING STORMS PERSIST...THEY WILL BE CAPABLE OF
   HAIL AND DAMAGING WINDS AS THEY MOVE/DEVELOP EWD INTO THE OZARKS.
   
   ...GULF COAST STATES/SRN APPALACHIANS...
   
   RESIDUAL OUTFLOW BOUNDARY ARCING FROM WRN NC INTO NRN PARTS OF AL/GA
   AS OF LATE MORNING IS EXPECTED TO SERVE AS THE FOCUS FOR STORM
   REGENERATION AND/OR RE-INTENSIFICATION OF LINGERING NOCTURNAL TSTM
   ACTIVITY.  12Z REGIONAL SOUNDINGS SHOW THAT INFLOW AIR MASS IS
   CHARACTERIZED BY STEEP MIDLEVEL LAPSE RATES OF AROUND 7.5 C/KM AND A
   MOIST BOUNDARY LAYER...RESULTING IN AN ALREADY MODERATELY TO
   STRONGLY UNSTABLE ENVIRONMENT.  INCREASED DIABATIC WARMING SHOULD
   ACT TO FURTHER DESTABILIZE BOUNDARY LAYER WITH MLCAPE VALUES
   APPROACHING 3000-3500 J/KG.  THOUGH REGION WILL REMAIN DISPLACED
   FROM STRONGER MID TO UPPER-LEVEL WIND FIELD...THE THERMODYNAMIC
   ENVIRONMENT WILL BE QUITE CONDUCIVE FOR UPSCALE GROWTH OF STORMS
   INTO ONE OR MULTIPLE FORWARD-PROPAGATING CONVECTIVE SYSTEMS WITH
   ATTENDANT RISKS OF DAMAGING WINDS AND HAIL.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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