Sep 1, 2012 0600 UTC Day 1 Convective Outlook
Updated: Sat Sep 1 05:09:29 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120901 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120901 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
20120901 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
20120901 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 010505
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1205 AM CDT SAT SEP 01 2012
   
   VALID 011200Z - 021200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN AR INTO SERN MO AND
   EXTREME SWRN IL...
   
   ...SYNOPSIS...
   
   REMNANT OF TD ISAAC LOCATED OVER WRN MO IS EMBEDDED WITHIN SYNOPTIC
   UPPER RIDGE. WITH WEAK STEERING FLOW ALOFT...THIS FEATURE WILL MOVE
   VERY SLOWLY EWD...REACHING SWRN IL BY 12Z SUNDAY. OTHERWISE...THE
   SYNOPTIC PATTERN WILL BE CHARACTERIZED BY A MEAN TROUGH IN THE WRN
   AND NERN U.S. WITH HIGH PRESSURE DOMINATING FROM THE CNTRL AND SRN
   PLAINS THROUGH THE SERN STATES. THE NRN STREAM SHORTWAVE TROUGH NOW
   OVER BRITISH COLUMBIA AND PACIFIC NW WILL CONTINUE EWD INTO ALBERTA
   AND NRN MT LATER SATURDAY ACCOMPANIED BY A COLD FRONT. VORTICITY
   MAXIMA EMBEDDED WITHIN WEAKER SRN STREAM TROUGH WILL SHEAR EWD AS
   THEY MOVE INTO A CONFLUENT FLOW REGIME OVER THE GREAT BASIN AREA.
   
   ...PORTIONS OF LOWER THROUGH MID MS VALLEY AND WRN TN VALLEY...
   
   REMNANTS OF ISAAC CONTINUE TO WEAKEN AND IS ENTRAINING DRYER AIR
   ALOFT INTO ITS SRN FLANK. THIS SUGGESTS THE BEST POTENTIAL FOR SFC
   HEATING AND GREATER INSTABILITY MAY DEVELOP FROM AR...SRN MO INTO
   WRN TN SATURDAY. A VORT MAX IS FORECAST TO ROTATE AROUND THE SRN
   PERIPHERY OF THE UPPER LOW...AND STORMS WILL LIKELY REDEVELOP WITHIN
   EVOLVING LOW LEVEL CONVERGENCE BAND FROM PARTS OF AR INTO SERN MO AS
   THE BOUNDARY LAYER DESTABILIZES. MODELS MAINTAIN A 40 KT SWLY LLJ
   ALONG SERN FLANK OF THE CIRCULATION WHERE 0-2 KM SHEAR /ALTHOUGH
   LESS THAN PREVIOUS DAYS/ MAY BE MARGINALLY  SUFFICIENT FOR A THREAT
   FOR LOW LEVEL MESOCYCLONES AND A COUPLE OF TORNADOES. ISOLATED
   STRONG TO DAMAGING GUSTS MAY ALSO OCCUR WITH THE STRONGER
   STORMS...ESPECIALLY WHERE SBCAPE SHOULD BE MAXIMIZED FROM CNTRL
   THROUGH NERN AR INTO SERN MO.
   
   ...INTERMOUNTAIN REGION/EASTERN GREAT DIVIDE...
   
   CORRIDOR OF MODERATE SOUTHWESTERLY MID LEVEL FLOW /35-40 KT/ WILL
   EXTEND FROM SOUTHERN CA/DESERT SOUTHWEST TO THE NORTHERN ROCKIES ON
   SATURDAY. STORMS WILL LIKELY DEVELOP OVER THE HIGHER TERRAIN
   POSSIBLY AIDED BY EWD SHEARING VORT MAX. SOME OF THESE TSTMS MAY BE
   CAPABLE OF STRONG GUSTY WINDS AND/OR MARGINAL HAIL.
   
   ...AZ...
   
   TSTMS ARE EXPECTED TO BE A BIT MORE PREVALENT ON SATURDAY AS
   MOISTURE GRADUALLY INCREASES INTO PARTS OF AZ/LOWER CO RIVER VALLEY
   OVER THE NEXT 24-48 HR. THIS INCREASE IN MOISTURE COUPLED WITH A
   MODESTLY ENHANCED BELT OF SOUTH-SOUTHWESTERLY FLOW ALOFT MAY ALLOW
   FOR A FEW SUSTAINED/STRONGER TSTMS CAPABLE OF WIND AND/OR MARGINAL
   HAIL.
   
   ...CNTRL/EASTERN MT...
   
   HEIGHT FALLS ARE EXPECTED TO OCCUR OVER THE REGION ESPECIALLY INTO
   SATURDAY AFTERNOON/NIGHT IN ASSOCIATION WITH THE PROGRESSIVE
   SHORTWAVE TROUGH. ISOLATED TSTMS MAY DEVELOP OVER THE HIGHER TERRAIN
   AHEAD OF THE FRONT AND SHIFT NEWD THROUGH CNTRL AND ERN MT. IN SPITE
   OF STEEP LAPSE RATES/INCREASING VERTICAL SHEAR...THE PRIMARY
   LIMITATION WILL BE LIMITED MOISTURE/BUOYANCY...ALTHOUGH A DEEPLY
   MIXED BOUNDARY LAYER MAY CONTRIBUTE TO GUSTY WINDS WHERE TSTMS
   DEVELOP SATURDAY AFTERNOON/EARLY EVENING.
   
   ..DIAL/MOSIER.. 09/01/2012
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z