Sep 4, 2012 0600 UTC Day 1 Convective Outlook
Updated: Tue Sep 4 06:11:31 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120904 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120904 1200 UTC Day 1 Tornado Probabilities 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
20120904 1200 UTC Day 1 Damaging Wind Probabilities 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
20120904 1200 UTC Day 1 Large Hail Probabilities 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 040607
   
   DAY 1 CONVECTIVE OUTLOOK RESENT 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0107 AM CDT TUE SEP 04 2012
   
   VALID 041200Z - 051200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID MO
   VALLEY AND UPPER MS VALLEY...
   
   ...MID MO VALLEY/UPPER MS VALLEY...
   WESTERLY FLOW WILL BE IN PLACE ACROSS THE NCNTRL STATES TODAY AS AN
   UPPER-LEVEL TROUGH MOVES INTO THE NRN PLAINS. AHEAD OF THE
   UPPER-LEVEL TROUGH...MODEL FORECASTS INDICATE THAT SEVERAL
   DISTURBANCES WILL BE PRESENT IN THE FLOW MOVING ACROSS THE REGION
   FROM WEST TO EAST. AT THE SFC...A COLD FRONT IS FORECAST TO ADVANCE
   SEWD ACROSS THE NRN AND CNTRL PLAINS WITH A CORRIDOR OF LOW-LEVEL
   MOISTURE IN PLACE FROM THE MID MO VALLEY NEWD INTO THE UPPER MS
   VALLEY. AS SFC TEMPS WARM DURING THE DAY...SCATTERED THUNDERSTORMS
   SHOULD INITIATE ALONG THE WRN EDGE OF THE MOIST CORRIDOR FROM WRN
   UPPER MI SWWD ACROSS WI...IA INTO ERN NEB. SEVERAL CONVECTIVE
   CLUSTERS ARE EXPECTED TO PERSIST ACROSS THE REGION FROM THE LATE
   AFTERNOON INTO THE EVENING.
   
   FORECAST SOUNDINGS ALONG THE CORRIDOR OF MODERATE INSTABILITY FROM
   WI SWWD INTO IA AT 00Z/WED GENERALLY SHOW AROUND 40 KT OF DEEP LAYER
   SHEAR. THIS SHEAR ENVIRONMENT SHOULD SUPPORT SEVERE STORM
   DEVELOPMENT AS CELLS INITIATE DURING THE LATE AFTERNOON. LARGE-SCALE
   ASCENT IS FORECAST TO REMAIN RELATIVELY WEAK AND SHOULD ENABLE
   STORMS TO REMAIN DISCRETE. THIS FACTOR ALONG WITH STEEP LAPSE RATES
   MAY BE FAVORABLE FOR ISOLATED LARGE HAIL ESPECIALLY WITH STORMS THAT
   ROTATE. LARGE TEMP-DEWPOINT SPREADS MAY ALSO ENHANCE DOWNDRAFT
   ACCELERATION AND DAMAGING WIND GUSTS WILL CERTAINLY BE POSSIBLE WITH
   THE BETTER ORGANIZED STORM CLUSTERS. THE GREATEST SEVERE THREAT
   COULD EXIST ACROSS THE NERN PART OF THE SLIGHT RISK AREA DURING THE
   EARLY EVENING WHERE LOW-LEVEL FLOW IS FORECAST TO BE STRONGER.
   
   ...CNTRL GULF COAST STATES...
   AN UPPER-LEVEL TROUGH WILL MOVE SLOWLY EWD ACROSS THE ERN GULF COAST
   STATES TODAY. ON THE WRN EDGE OF THE UPPER-LEVEL TROUGH...A CORRIDOR
   OF MODERATE INSTABILITY IS FORECAST TO DEVELOP THIS AFTERNOON ACROSS
   MS AND WRN AL. AS SFC TEMPS WARM...SCATTERED TO NUMEROUS
   THUNDERSTORMS SHOULD AGAIN INITIATE ALONG THE INSTABILITY CORRIDOR
   THIS AFTERNOON. FORECAST SOUNDINGS ACROSS SE MS AND SRN AL AT 21Z
   GENERALLY SHOW DEEP LAYER SHEAR IN THE 30 TO 35 KT SUGGESTING SEVERE
   STORM DEVELOPMENT WILL BE POSSIBLE. LINE SEGMENTS THAT HAVE ACCESS
   TO THE STRONGEST INSTABILITY MAY BE CAPABLE OF PRODUCING ISOLATED
   DAMAGING WIND GUSTS ESPECIALLY AS LOW-LEVEL LAPSE RATES STEEPEN
   DURING THE LATE AFTERNOON. AT THIS POINT...UNCERTAINTY REGARDING
   WHERE THE STRONGEST INSTABILITY DEVELOPS PRECLUDES A SLIGHT RISK
   ATTM.
   
   ..BROYLES/MOSIER.. 09/04/2012
   
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