Aug 1, 2008 0600 UTC Day 1 Convective Outlook
Updated: Fri Aug 1 05:34:14 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20080801 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080801 1200 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20080801 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080801 1200 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 010530
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 AM CDT FRI AUG 01 2008
   
   VALID 011200Z - 021200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS GREAT LAKES/OH VALLEY
   REGIONS TO MID MS VALLEY...
   
   ...SYNOPSIS...
   MORE HIGHLY AMPLIFIED UPPER AIR PATTERN FCST TO DEVELOP ACROSS NRN
   HALF OF CONUS...AS WRN MEAN RIDGE FURTHER AMPLIFIES AND TROUGHING
   DEEPENS OVER GREAT LAKES.  LATTER PROCESS WILL BE AIDED BY SEWD
   MOVEMENT AND STRENGTHENING OF SHORTWAVE TROUGH -- NOW BREAKING OFF
   SERN END OF SASK TROUGH...AND EVIDENT IN MOISTURE CHANNEL IMAGERY
   INVOF MB/ONT BORDER.  BY 2/12Z...STG SHORTWAVE TROUGH SHOULD EXTEND
   FROM SRN ONT SWWD TO SSWWD ACROSS WV.  BY 2/00Z...ASSOCIATED SFC
   COLD FRONT -- NOW MOVING SWD OVER IA AND CENTRAL PLAINS -- SHOULD
   REACH SRN ONT...WRN OH...SRN IL...AND CENTRAL MO...BECOMING
   QUASISTATIONARY WWD ACROSS CENTRAL KS...THEN DIFFUSE WARM FRONT OVER
   W-CENTRAL/W KS AND E-CENTRAL/NERN CO.
   
   BY 2/12Z...NWRN FRINGE OF HIGH PLAINS WARM FRONTAL SEGMENT WILL
   BUILD/MOVE NWD AND LINK WITH LEE-SIDE SFC LOW INVOF SWRN ND/SERN
   MT/NWRN SD.  THIS LOW SHOULD DEVELOP IN RESPONSE TO MID-UPPER
   SHORTWAVE TROUGH NOW APCHG BC/WA COAST...AND FCST OVER CANADIAN
   ROCKIES BY END OF PERIOD.  OCCLUDED FRONTAL ZONE SHOULD EXTEND NWD
   FROM SFC LOW ACROSS WRN ND OVER SERN SASK AT THAT TIME...WITH COLD
   FRONT SWWD OVER WRN WY.
   
   ...GREAT LAKES/OH VALLEY REGIONS TO MID MS VALLEY...
   SCATTERED TSTMS EXPECTED TO DEVELOP ALONG/AHEAD OF FRONT OVER LOWER
   MI/NWRN OH/ERN INDIANA AREA DURING AFTERNOON.  PATTERN FAVORS
   RELATIVELY CONCENTRATED DAMAGING WIND PROBABILITIES ACROSS OH WHERE
   ACTIVITY MAY CONSOLIDATE INTO QUASI-LINEAR OR BOWING CONVECTIVE
   SYSTEM AND MOVE SEWD TOWARD WV.  FCST THERMODYNAMIC PROFILES SUGGEST
   PLUME OF FAVORABLY RICH LOW LEVEL MOISTURE WILL ADVECT EWD ACROSS
   THIS REGION FROM SFC THROUGH 850 MB...COMBINING WITH SFC DIABATIC
   HEATING TO BOOST MLCAPES INTO 2000-3000 J/KG RANGE
   INDIANA/OH...DECREASING EWD INTO PA.  STG WLY COMPONENT OF BOUNDARY
   LAYER FLOW AHEAD OF FRONT WILL ACT TO REDUCE CONVERGENCE AND
   HODOGRAPH SIZE...BUT ALSO...WILL YIELD NEARLY UNIDIRECTIONAL
   DEEP-LAYER WIND PROFILES.  MEANWHILE...DEEP-LAYER SPEED SHEAR IS
   FCST TO STRENGTHEN THROUGHOUT DAY ALONG AND JUST AHEAD OF SFC FRONT
   AS TROUGH ALOFT APCHS AND HEIGHT GRADIENTS TIGHTEN...BENEATH NRN
   PORTION OF STRONGLY DIFFLUENT UPPER WINDS.
   
   LOW LEVEL MOISTURE AND MID-UPPER LEVEL LAPSE RATES ARE EXPECTED TO
   INCREASE WITH WWD EXTENT ALONG TRAILING PORTION COLD FRONT...AT
   LEAST INTO CENTRAL MO.  HOWEVER...OFFSETTING FACTORS INCLUDE
   WEAKENING CONVERGENCE WITH WWD EXTENT.  CAPPING WILL LIMIT
   CONVECTIVE COVERAGE/DURATION DURING MOST FAVORABLE THERMODYNAMIC
   PERIOD OF LATE AFTERNOON.  ANY TSTMS THAT CAN DEVELOP MAY BRIEFLY
   PRODUCE HAIL OR STG-SVR DOWNBURSTS.
   
   ...NRN HIGH PLAINS...LATE PERIOD...
   COMBINATION OF MOIST AND WARM ADVECTION WILL INCREASE LOW LEVEL
   THETAE THROUGHOUT LATTER HALF OF PERIOD AHEAD OF SFC LOW AND COLD
   FRONT...AND ALONG AND N OF SFC WARM FRONT.  DESPITE RATHER SCANT SFC
   MOISTURE...HIGH-BASED TSTMS WITH STG WINDS MAY DEVELOP OVER
   CENTRAL/ERN MT DURING AFTERNOON.  MORE PLAUSIBLE SCENARIO IS FOR
   ELEVATED TSTMS TO FORM LATE IN PERIOD FROM ERN MT ACROSS WRN ND. 
   STEEP LOW-MIDLEVEL LAPSE RATES AND FAVORABLE DEEP-LAYER SHEAR WILL
   SUPPORT CONDITIONAL HAIL AND STG-SVR GUST POTENTIAL WITH SOME OF
   THIS ACTIVITY.  MAIN CONCERN WILL BE QUALITY/BREADTH OF SUPPORTIVE
   MOISTURE RETURN FIELD.
   
   ...SERN CONUS...
   ONGOING ACTIVITY HAS SHUNTED COLLECTIVE OUTFLOW BOUNDARY WELL S OF
   RESIDUAL/WEAKENING FRONTAL ZONE.  FORMER BOUNDARY...ALONG WITH SEA
   BREEZE FRONTS AND NEWER OUTFLOWS DURING PERIOD...SHOULD BE PRIMARY
   FOCI FOR DEVELOPMENT FROM SRN ATLANTIC COASTAL PLAIN WWD ACROSS GULF
   COASTAL STATES...INTO ARKLATEX REGION.  ALTHOUGH LOW LEVEL FLOW AND
   DEEP-LAYER SHEAR EACH ARE EXPECTED TO BE RATHER WEAK...SEVERAL
   RELATIVELY DENSE CONCENTRATIONS OF MULTICELLULAR TSTMS ARE LIKELY TO
   EVOLVE AND CONCENTRATE MRGL SVR WIND POTENTIAL DURING AFTERNOON.
   
   ..EDWARDS/SMITH.. 08/01/2008
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z