Sep 1, 2011 1730 UTC Day 2 Convective Outlook
Updated: Thu Sep 1 17:22:04 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110901 1730 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20110901 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 011720
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1220 PM CDT THU SEP 01 2011
   
   VALID 021200Z - 031200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN WI INTO LOWER MI...
   
   ...SYNOPSIS...
   A BROAD UPPER TROUGH WITH 60-70 KT MID LEVEL JET CORE WILL STRETCH
   FROM THE NRN ROCKIES EWD ACROSS THE NRN PLAINS AND INTO THE GREAT
   LAKES. A LEAD DISTURBANCE WILL MOVE FROM NRN MN/WRN ONTARIO NEWD
   TOWARD HUDSON BAY...WHILE ANOTHER VORTICITY MAX SETTLES INTO MT WITH
   LOW CENTERED OVER SK. AT THE SURFACE...A COLD FRONT ASSOCIATED WITH
   THE LEAD WAVE WILL EXTEND FROM NRN MN INTO SRN WI AND BECOMING
   STATIONARY INTO KS LATE. AMPLE MOISTURE WILL EXIST AHEAD OF THE
   FRONT FOR SCATTERED THUNDERSTORMS...A FEW OF WHICH MAY BE SEVERE.
   
   TO THE E...AN UPPER HIGH WILL BE CENTERED OVER THE OH/TN VALLEY
   REGION...WITH NLY FLOW ALOFT FROM THE APPALACHIANS TO THE E COAST ON
   ERN PERIPHERY OF THE HIGH. HERE...A WEAK SURFACE TROUGH IS FORECAST
   DURING THE AFTERNOON WHICH MAY BE ENOUGH FOR A FEW STRONG TO SEVERE
   STORMS.
   
   ELSEWHERE...A TROPICAL CYCLONE IS FORECAST TO STRENGTHEN OVER THE
   NRN GULF OF MEXICO THROUGH THE PERIOD WHILE DRIFTING IN A GENERAL
   NWD DIRECTION...AFFECTING THE N CNTRL GULF COAST.
   
   ...SRN WI INTO MI AND EXTREME NRN IL...
   SCATTERED SHOWERS AND STORMS SHOULD BE ONGOING NEAR A COLD FRONT
   FROM NEB INTO UPPER MI EARLY ON FRI...WITH STORMS EVOLVING DURING
   THE DAY AND SHIFTING EWD ACROSS WI AND INTO LOWER MI BY AFTERNOON.
   STEEP LAPSE RATES AND AMPLE INSTABILITY WILL EXIST AS WELL AS DEEP
   LAYER FLOW FOR SEVERE STORMS TO BECOME ORGANIZED. RELATIVELY
   STRAIGHT HODOGRAPHS SUGGEST MINIMAL SUPERCELL THREAT WITH CLUSTERS
   OR LINE SEGMENTS MORE LIKELY. AS SUCH...BOTH WIND AND HAIL WILL BE A
   THREAT.
   
   ...SRN LA/MS/AL...
   MODELS INDICATE STRENGTHENING WIND FIELDS...AS WELL AS PRECIPITABLE
   WATER ACROSS MUCH OF SRN LA INTO SRN MS/AL WITH THE APPROACHING
   TROPICAL CYCLONE. IF THIS DEVELOPS AS EXPECTED...HODOGRAPHS WOULD
   FAVOR ROTATING STORMS WITHIN RAIN BANDS...AND GIVEN DEWPOINTS IN THE
   UPPER 70S F...THE VIRTUAL TEMPERATURE CORRECTION WOULD YIELD
   SUFFICIENT CAPE FOR A FEW TORNADOES. GIVEN THE SYSTEM IS IN THE
   FORMATIVE STAGE...WILL DEFER A POSSIBLE TC TORNADO-DRIVEN SLIGHT
   RISK TO LATER OUTLOOKS.
   
   ...SWRN PA/WV INTO WRN VA AND NC...
   WEAK LOW LEVEL WARM ADVECTION WILL EXIST WITH 850 THETA-E ADVECTION
   OUT OF THE NW. WEAK CONVERGENCE IS FORECAST BY AFTERNOON...AND WITH
   STRONG HEATING...CONVECTIVE INHIBITION SHOULD BECOME NEGLIGIBLE.
   FORCING FOR CONVECTION WILL BE THE MAIN LIMITING FACTOR TO GREATER
   STORM COVERAGE. HOWEVER...IT DOES APPEAR THAT AT LEAST ISOLATED
   STORMS MAY OCCUR...WITH A CONDITIONAL THREAT OF BOTH HAIL AND GUSTY
   WINDS
   
   ..JEWELL.. 09/01/2011
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z