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 190426
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1126 PM CDT SUN SEP 18 2011
   
   VALID 191200Z - 201200Z
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   AN UPPER TROUGH AXIS ACROSS THE MS RIVER VALLEY WILL WEAKEN AS IT
   EJECTS NEWD ACROSS THE OH VALLEY AND INTO THE NERN STATES BY TUE. AT
   THE SURFACE...A WEAK TROUGH AND COLD FRONT WILL STRETCH FROM LOWER
   MI SWWD INTO SE TX AT 00Z...WITH MID TO UPPER 60S BOUNDARY LAYER
   DEWPOINTS AHEAD OF IT.
   
   TO THE W...AN UPPER WAVE IS FORECAST TO AMPLIFY ACROSS MT DURING THE
   AFTERNOON...SPREADING INTO THE NRN PLAINS OVERNIGHT. A DEVELOPING
   COLD FRONT AS WELL AS A DEEPENING SURFACE LOW WILL BOTH MAXIMIZE
   FORCING FOR ASCENT ACROSS THIS REGION...BUT MOISTURE WILL BE LIMITED
   FOR STORMS.
   
   ...ERN MT INTO THE DAKOTAS...
   CONVERGENCE WILL INCREASE MARKEDLY DURING THE AFTERNOON ACROSS ERN
   MT AS A COLD FRONT DEVELOPS. MODESTLY STEEP LOW TO MID LEVEL LAPSE
   RATES WILL EXIST AHEAD OF THE FRONT DUE TO HEATING...BUT MOISTURE
   WILL BE MEAGER WITH MUCAPE OF 100-200 J/KG EXPECTED. HOWEVER...GIVEN
   VERY STRONG WIND FIELDS AND BOUNDARY LAYER MIXING...A FEW
   CONVECTIVELY ENHANCED WIND GUSTS WILL BE POSSIBLE. THE THREAT OF
   HIGH BASED/STRONGLY FORCED SEVERE WIND GUSTS MAY PERSIST INTO THE
   EVENING ACROSS NWRN SD AND INTO ND AS BOUNDARY LAYER LAPSE RATES
   REMAIN STEEP DUE TO MIXING...AND FORCING INCREASES FURTHER NEAR THE
   SURFACE LOW/FRONT.
   
   ...LOWER OH/MS VALLEY SWWD INTO SERN TX...
   RAIN AND STORMS WILL BE ONGOING MON MORNING OVER A LARGE AREA
   STRETCHING FROM ERN TX/LA INTO NEWD TO LOWER MI NEAR A WEAK SURFACE
   TROUGH. AS THE UPPER TROUGH DEPARTS AND WEAKENS...WIND FIELDS WILL
   SLACKEN ACROSS THE REGION...AND GIVEN WIDESPREAD PRECIP AND
   CLOUDS...SUBSTANTIAL DESTABILIZATION IS NOT EXPECTED.
   THIS...COMBINED WITH WEAK SHEAR...SHOULD PRECLUDE MUCH OF A SEVERE
   THREAT.
   
   ..JEWELL/ROGERS.. 09/19/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z