Nov-23-2004 1730 UTC Day 2 Convective Outlook
Updated: Tue Nov 23 17:00:47 UTC 2004
Categorical Graphic
20041123 1730 UTC Day 2 Outlook Graphic
Probablistic Graphic
20041123 1730 UTC Day Probabilitic Graphic
   SPC AC 231658
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1058 AM CST TUE NOV 23 2004
   
   VALID 241200Z - 251200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SW
   7R4 25 ESE HEZ 45 SE GWO UOX 35 ESE JBR 15 SW CGI 45 SW BMG 30 SSE
   MIE 20 ESE MFD 20 NNE HLG 30 SE PKB 10 E 5I3 50 SSE TYS 15 SSW SPA
   25 E GSO 10 NNE ORF ...CONT... 25 SE JAX 15 SW CTY.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SE DAB 15 SW FMY
   ...CONT... 25 S LCH 35 ESE MLU 40 NNW GLH 45 ENE LIT 50 N LIT 15 ENE
   HRO 40 E SGF 35 W MIE 45 SE DTW ...CONT... 55 N BML 25 SE AUG.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE OH/TN
   VALLEYS...CENTRAL GULF COAST...SRN APPALACHIANS...AND SRN ATLANTIC
   COAST...
   
   ...SYNOPSIS...
   ANOTHER ACTIVE SEVERE THUNDERSTORM DAY IS LIKELY AS STRONG UPPER
   TROUGH SHIFTS EWD ACROSS THE GREAT LAKES/GULF COAST REGIONS. 
   LEADING SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW CENTER WILL
   EJECT RAPIDLY NEWD ACROSS THE OH RIVER VALLEY AND INTO THE ERN GREAT
   LAKES DURING THE AFTERNOON WEDNESDAY...WHILE ANOTHER STRONG SYSTEM
   DIGS AROUND BASE OF LONG WAVE TROUGH AND INTO THE SRN APPALACHIANS
   DURING THE LATTER HALF OF THE PERIOD.  THEREFORE...A BROAD REGION OF
   ENHANCED LOW AND DEEP LAYER SHEAR WILL OVERSPREAD A LARGE PORTION OF
   THE ERN U.S. WHERE BOUNDARY LAYER WILL BECOME INCREASINGLY MOIST AND
   UNSTABLE.  TWO PRIMARY AREAS OF SEVERE THREAT ARE LIKELY...ONE NEAR
   THE LOW CENTER AND INVOF STEEPER MID LEVEL LAPSE RATES SPREADING
   INTO THE OH AND TN RIVER VALLEYS...WITH ANOTHER NEARER THE DEEP
   MOISTURE AND ENHANCED LOW LEVEL SHEAR ACROSS THE CENTRAL GULF COAST
   REGION.
   
   ...OH INTO THE TN RIVER VALLEYS...
   WIDESPREAD CONVECTION MAY BE ONGOING WITHIN STRONG LOW LEVEL WAA
   REGIME OVER THE MID MS AND LOWER OH RIVER VALLEYS WEDNESDAY MORNING.
    THIS ACTIVITY WILL RAPIDLY SPREAD NEWD WELL AHEAD OF PRIMARY
   SURFACE CONVERGENCE ALONG SURFACE COLD FRONT.  MODELS SUGGEST
   SURFACE DEW POINTS WILL INCREASE INTO THE UPPER 50S/LOWER 60S BY THE
   EARLY AFTERNOON...WITH FORECAST WIND PROFILES INDICATING VERY STRONG
   LOW AND DEEP LAYER SHEAR.  SHOULD HEATING/INSTABILITY DEVELOP WITH
   LEADING CONVECTION...SEVERE THREAT MAY INCREASE WITH IT AS IT SHIFTS
   NEWD INTO THE UPPER OH RIVER VALLEY THROUGH THE DAY.  OTHERWISE...
   EXPECT SOME CLEARING TO OCCUR AHEAD OF APPROACHING COLD FRONT IN
   WAKE OF EARLIER STORMS.  ETA AND ETAKF SUGGEST TEMPERATURES IN THE
   MID TO UPPER 60S BY 21Z...WITH MLCAPES FROM 500-1000 J/KG.  GIVEN
   DEGREE OF SHEAR AND PRESENCE OF LOW LEVEL CONVERGENCE...EXPECT LOW
   TOPPED SUPERCELLS AND SMALL LINES WILL DEVELOP INTO THE EARLY
   EVENING.  CAPE AND SHEAR PARAMETERS SUGGEST ISOLATED SIGNIFICANT
   SEVERE WILL BE POSSIBLE.  UNCERTAINTY REGARDING INSTABILITY APPEARS
   TOO GREAT TO UPGRADE TO MODERATE ATTM.
   
   ...CENTRAL GULF COAST REGION...
   ONGOING STRONG TO SEVERE SQUALL LINE IS EXPECTED TO EXTEND FROM
   NRN/WRN AL INTO SERN LA AT THE BEGINNING OF THE PERIOD WITH EMBEDDED
   LEWPS AND POSSIBLE PRE-SQUALL LINE SUPERCELLS WITHIN WEAKLY CAPPED
   AND STRONGLY SHEARED ENVIRONMENT. THIS ACTIVITY WILL SPREAD STEADILY
   EWD ACROSS THE SRN APPALACHIANS INTO THE NERN GULF OF MEXICO THROUGH
   THE DAY.  THOUGH LAPSE RATES WILL REMAIN WEAK WITHIN DEEP MOIST
   PROFILES...SIGNIFICANT LOW AND DEEP LAYER SHEAR OVERSPREADING UPPER
   60F/LOWER 70F SURFACE DEW POINTS SUGGEST TORNADO POTENTIAL /SOME OF
   WHICH COULD BE STRONG/ WILL PERSIST ALONG AND SOUTH OF WARM FRONT. 
   MODERATE INSTABILITY AND HIGHEST SEVERE PROBABILITIES WILL LIKELY
   REMAIN CONFINED TO AREAS NEARER THE COAST...HOWEVER ISOLATED
   TORNADOES/WIND DAMAGE MAY OCCUR NWD INTO THE SRN APPALACHIANS. 
   UNCERTAINTY REGARDING EXTENT/COVERAGE OF PRE-SQUALL CONVECTION AND
   ASSOCIATED INSTABILITY WARRANT MAINTAINING SLIGHT RISK FOR
   NOW...THOUGH UPGRADE MAY BE NEEDED IN LATER OUTLOOKS.
   
   ...SRN ATLANTIC COAST INTO THE DELMARVA...
   BY THE END OF THE PERIOD...VERY STRONG LOW AND DEEP LAYER WINDS WILL
   OVERSPREAD THIS REGION AHEAD OF APPROACHING UPPER TROUGH.  GFS
   INDICATES 500 MB WINDS IN EXCESS OF 90 KT OVER ERN NC AND THE
   DELMARVA BY 25/12Z.  GIVEN INFLUX OF ATLANTIC MOISTURE WITHIN
   INCREASING SSELY BOUNDARY LAYER FLOW...AND RESULTANT DEVELOPMENT OF
   MARGINAL INSTABILITY...THREAT OF SEVERE THUNDERSTORMS IN THE FORM OF
   SMALL LINES AND SUPERCELLS MAY DEVELOP LATE IN THE PERIOD ACROSS
   THIS REGION.  WIND DAMAGE AND ISOLATED TORNADOES WILL BE PRIMARY
   SEVERE THREATS SHOULD STORMS BE ABLE TO TAP MOIST BOUNDARY LAYER.
   
   ..EVANS.. 11/23/2004
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z