Sep 1, 2012 1300 UTC Day 1 Convective Outlook
Updated: Sat Sep 1 12:39:27 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120901 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120901 1300 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 1300 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 1300 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 011235
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0735 AM CDT SAT SEP 01 2012
   
   VALID 011300Z - 021200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF AR NEWD INTO SRN
   IL...
   
   ...SYNOPSIS...
   REMNANT ISAAC CIRCULATION WILL GRADUALLY COME UNDER THE INFLUENCE OF
   THE LARGER SCALE WLYS THIS PERIOD AS THE LOW CENTER CEASES ITS
   WWD/NWWD MOTION AND BEGINS TO MOVE EAST ACROSS MO AND INTO WRN IL
   THROUGH EARLY SUNDAY. WHILE UPPER RIDGING DOMINATES THE CNTRL AND
   SRN U.S...MODEST MID LEVEL FLOW AND TRANSIENT SHORTWAVE DISTURBANCES
   WILL CROSS PARTS OF THE GREAT BASIN/NRN ROCKIES AND NRN PLAINS...AS
   WELL AS PORTIONS OF THE NORTHEAST/MID-ATLANTIC.
   
   ...AR TO SRN IL...
   MODELS ARE FORECASTING AN AXIS OF STRONGER DESTABILIZATION WITHIN
   THE SRN/SERN FLANK OF REMNANT ISAAC CIRCULATION LATER TODAY. DRY
   SLOT WRAPPING INTO THE CIRCULATION FROM OK/KS INTO AR/MO PER MORNING
   SATELLITE IMAGERY APPEARS TO COINCIDE WITH THE CORRIDOR OF GREATER
   POTENTIAL DESTABILIZATION LATER TODAY FROM AR NEWD INTO SRN IL.
   GIVEN PLUME OF RICH TROPICAL MOISTURE AND TEMPERATURES CLIMBING INTO
   THE 90S IN THOSE AREAS WITH GREATER SFC HEATING...MLCAPE OF
   1500-2000 J/KG AND WEAK INHIBITION SHOULD RESULT. PERSISTENT ASCENT
   AROUND THE LOW CIRCULATION WILL AID/SUSTAIN TSTMS MOVING INTO THE
   INSTABILITY AXIS WHERE THE COMBINATION OF LOW LEVEL CAPE AND
   HODOGRAPH CURVATURE WILL CONTRIBUTE TO STRONGER UPDRAFT ROTATION AND
   THE CHANCE FOR A COUPLE OF TORNADOES AND/OR DAMAGING DOWNBURST WIND
   EVENTS.
   
   ...NRN GREAT BASIN...
   A SERIES OF RELATIVELY FAST-MOVING SHORTWAVE TROUGHS WILL SPREAD
   NEWD FROM THE GREAT BASIN TO THE NRN PLAINS THROUGH TONIGHT. ONE OF
   THESE FEATURES WAS TRACKING ACROSS NRN UT THIS MORNING ACCOMPANIED
   BY RELATIVELY WIDESPREAD CONVECTION. WHILE SOME CONVECTIVE CLOUD
   COVER AND GENERALLY DRY BOUNDARY LAYER AWAY FROM THE CONVECTION WILL
   LIMIT DESTABILIZATION...SOME LOCATIONS WILL EXPERIENCE INSOLATION
   SUFFICIENT TO BOOST MLCAPE INTO THE 500-1000 J/KG RANGE. DYNAMIC
   LIFT...TERRAIN INFLUENCES...AND RELATIVELY FAST MID LEVEL SWLY FLOW
   ON THE ORDER OF 40KT...SHOULD SUPPORT CLUSTERS OF MORE
   ORGANIZED/PERSISTENT STORMS POSING BOTH HAIL AND WIND HAZARDS
   THROUGH THE AFTERNOON. THE FOCUS FOR MORE SUBSTANTIAL SEVERE STORM
   COVERAGE CURRENTLY REMAINS MASKED BY EARLY DAY STORMS AND
   ILL-DEFINED SFC FEATURES. HOWEVER...SOME OF THIS REGION MAY REQUIRE
   GREATER SEVERE WEATHER PROBABILITIES IN LATER OUTLOOKS IF STORM
   CHARACTER AND EVOLUTION BECOME CLEARER.
   
   ...MID ATLANTIC...
   BACKDOOR FRONT WILL LIKELY REMAIN NORTH OF THE PA/MD BORDER WITH
   AREAS OF STRONGER DIURNAL DESTABILIZATION DEVELOPING ALONG/SOUTH OF
   THE FRONT FROM SRN PA ACROSS THE DELMARVA REGION AND INTO THE
   CAROLINAS. WHILE MID LEVEL FLOW ACROSS THE REGION IS FORECAST TO
   REMAIN MEAGER...WEAK HEIGHT FALLS TRAILING THE SHORT WAVE TROUGH
   MOVING OFF THE NEW ENGLAND COAST MAY PROMOTE TSTMS ACROSS THE WARM
   SECTOR ALONG AND EAST OF THE APPALACHIAN HIGHLANDS. A COUPLE OF
   STORMS MAY PRODUCE GUSTY WINDS CAPABLE OF TOPPLING TREES.
   
   ..CARBIN/ROGERS.. 09/01/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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