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 211235
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0735 AM CDT SAT JUL 21 2012
   
   VALID 211300Z - 221200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FOR PARTS OF
   CENTRAL/NRN LA AND E TX...
   
   ...SYNOPSIS...
   THE WEATHER PATTERN ACROSS THE CONUS WILL BE DOMINATED BY A LARGE
   UPPER HIGH OVER THE CENTRAL HIGH PLAINS...WITH THE MAIN BELT OF WLYS
   STRETCHING FROM THE PAC NW EWD ALONG THE CANADIAN BORDER TO THE
   UPPER GREAT LAKES.  A MONSOONAL MOISTURE PLUME PERSISTS FROM AZ NWD
   ACROSS UT/WY...AND A HIGH PW ENVIRONMENT WITH MODERATE-STRONG
   INSTABILITY REMAINS ACROSS THE GULF/SE ATLANTIC STATES...DOWNSTREAM
   FROM A WEAK MIDLEVEL TROUGH EXTENDING FROM PA TO THE MID SOUTH. THE
   PRIMARY FOCI FOR THUNDERSTORM DEVELOPMENT TODAY WILL BE A STALLED
   FRONT ACROSS THE NRN PLAINS...DAYTIME HEATING AND RESIDUAL OUTFLOW
   BOUNDARIES ACROSS THE SRN STATES...AND DAYTIME HEATING WITHIN THE
   MOISTURE PLUME FROM AZ TO WY.
   
   ...E TX TO THE CAROLINAS THIS AFTERNOON/EVENING...
   A WEAK MIDLEVEL TROUGH/CYCLONIC SHEAR AXIS IS DRIFTING SEWD ACROSS
   THE APPALACHIANS AND SWD OVER THE MID SOUTH...IN CONJUNCTION WITH A
   WEAK SURFACE FRONT.  SIMILAR TO YESTERDAY...THE STEEPER LAPSE RATES
   AND HOTTER SURFACE TEMPERATURES /RESULTING IN MLCAPE OF 3000-4000 J
   PER KG/ ARE EXPECTED ON THE WRN FRINGE OF THE OVERNIGHT SW LA
   MCS...AND W/SW OF THE ONGOING STORMS ACROSS NE LA AND CENTRAL MS. 
   NELY MIDLEVEL FLOW WILL SUPPORT A COUPLE OF SWWD-MOVING STORM
   CLUSTERS CAPABLE OF PRODUCING A FEW DAMAGING GUSTS AND MARGINALLY
   SEVERE HAIL THIS AFTERNOON/EVENING.  FARTHER E...LAPSE RATES AND
   BUOYANCY WILL BE WEAKER...BUT PULSE-TYPE STORMS WITH ISOLATED STRONG
   OUTFLOW WINDS WILL STILL BE POSSIBLE IN THE MOIST ENVIRONMENT FROM
   AL TO NC.
   
   ...NRN HIGH PLAINS TO SRN MN THROUGH TONIGHT...
   ONGOING CONVECTION ACROSS CENTRAL MN IS ASSOCIATED WITH LOW-LEVEL
   WAA AND AN EMBEDDED MCV NEAR BROOKINGS SD...BUT THIS CONVECTION IS
   EXPECTED TO WEAKEN CONSIDERABLY BY MIDDAY AS LOW-LEVEL FLOW VEERS
   AND WAA DIMINISHES.  LATER THIS AFTERNOON...NEW STORM DEVELOPMENT IS
   EXPECTED WITHIN THE MOISTURE PLUME ACROSS WY.  STORMS WILL SPREAD
   EWD FROM THE BLACK HILLS AREA BY LATE AFTERNOON AND PERSIST INTO
   TONIGHT ALONG A STALLED FRONT WHERE A NOCTURNAL INCREASE IN WAA IS
   AGAIN EXPECTED.  ISOLATED LARGE HAIL/DAMAGING WINDS WILL BE POSSIBLE
   THIS AFTERNOON THROUGH EARLY TONIGHT...PRIMARILY NE WY INTO
   WRN/CENTRAL SD.  THERE IS SOME POTENTIAL FOR A SLIGHT RISK UPGRADE
   LATER TODAY.
   
   A NARROW CORRIDOR OF MODERATE INSTABILITY WILL ALSO EXTEND NWWD INTO
   E/NE MT...AHEAD OF A WEAK SURFACE COLD FRONT ACCOMPANYING THE
   PRIMARY MIDLEVEL TROUGH EJECTING ENEWD OVER SK.  THERE WILL BE SOME
   POTENTIAL FOR ISOLATED SEVERE STORM DEVELOPMENT ALONG THE WIND SHIFT
   THIS AFTERNOON ACROSS E CENTRAL/NE MT...WITH STORMS SUBSEQUENTLY
   SPREADING EWD INTO WRN ND.  
   
   ...SRN AZ THIS AFTERNOON/EVENING...
   LOW-MIDLEVEL MOISTURE CONTINUES TO INCREASE OVER SRN AZ IN
   ASSOCIATION WITH A TROUGH IN THE ELYS OVER SONORA.  DAYTIME HEATING
   IN CLOUD BREAKS WILL SUPPORT SCATTERED THUNDERSTORM
   DEVELOPMENT...WITH THE STRONGER STORMS EXPECTED TO PROPAGATE INTO
   THE LOW DESERTS OF SW AZ...WHERE THE WARMEST TEMPERATURES AND
   GREATEST BUOYANCY WILL RESIDE.  MLCAPE NEAR 1000 J/KG AND PW NEAR
   1.75 INCHES WILL SUPPORT SUBSTANTIAL PRECIPITATION LOADING...AND THE
   POTENTIAL FOR ISOLATED STRONG OUTFLOW WINDS IN THE DEEPLY MIXED
   BOUNDARY LAYER.
   
   ..THOMPSON/MOSIER.. 07/21/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z