SPC AC 180601
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1201 AM CST TUE NOV 18 2003
   
   VALID 181200Z - 191200Z
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 WNW
   BVE 15 NNE HUM 40 WNW MEI 20 NW TUP 10 ENE MSL 60 S TYS 15 NE AND 35
   NNW AYS 20 WSW CTY.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 SSW
   BPT 30 SSW ELD 40 NNE TXK 30 ENE HRO 40 WNW MDH 15 ESE MVN 35 ENE
   OWB 10 NNE LOZ 30 SW CLT 25 S CHS ...CONT... 15 E JAX 20 N PIE.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 NW MLB SRQ.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SSW LRD 20 ENE AUS
   35 NE DAL 20 NNW MLC 40 WSW CNU 30 S IRK 20 ENE MLI 10 NW RFD 40 NE
   MTW 75 WNW ANJ ...CONT... 15 W ART 30 SW ELM 25 SE IPT 10 W TTN 30
   ENE ACY.
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS EXTREME SERN LA/ERN
   MS/AL/WRN-CENTRAL GA AND THE FL PANHANDLE...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER/MID MS VALLEY
   EWD ACROSS TN VALLEY TO SRN ATLANTIC STATES...
   
   ...SIGNIFICANT SEVERE EPISODE IS EXPECTED ACROSS MUCH OF THE GULF
   COAST REGION TODAY INTO TONIGHT...
   
   ...SYNOPSIS...
   PROGRESSIVE UPPER LEVEL FLOW PATTERN IS EXPECTED THIS PERIOD AS A
   FULL LATITUDE TROUGH CENTERED ACROSS THE CENTRAL U.S. AT THE START
   OF THE PERIOD TRACKS EWD REACHING THE GREAT LAKES AND CENTRAL GULF
   COAST STATES BY 12Z WEDNESDAY. AMPLIFICATION OF THE SRN PORTION OF
   THIS TROUGH IS EXPECTED TODAY AS IT MOVES ACROSS THE LOWER MS VALLEY
   TO GULF COAST STATES...WITH A CLOSED LOW FORMING DURING THE LATTER
   HALF OF THE PERIOD...GIVEN 90-150 METER 12-HR HEIGHT FALLS OVER
   MS/AL. MID-UPPER LEVEL WINDS WILL RESPOND TO THIS INTENSIFICATION
   WITH WSWLY 90 KT 500 MB FLOW ALONG THE UPPER TX COAST AT
   21Z...INCREASING TO AROUND 100 KT OVER SRN AL/WRN GA BY 19/12Z.
   
   AT THE SURFACE...COLD FRONT AT THE START OF THE PERIOD WILL EXTEND
   FROM A SURFACE LOW OVER ERN IA SWWD ACROSS ERN KS TO CENTRAL OK/
   NWRN TX...WITH A PRE-FRONTAL TROUGH EXTENDING SWD FROM THE MID MS
   VALLEY TO LA.
   
   ...GULF COAST STATES...
   MID-60S SURFACE DEWPOINTS CURRENTLY EXTEND FROM THE LOWER MS
   VALLEY...AND SEWD TO THE COASTAL PORTIONS OF THE GULF COAST STATES. 
   THIS AIR MASS WILL SURGE NWD ACROSS THE REST OF MS/AL/GA TODAY AS A
   WARM FRONT LIFTS NWD WELL INLAND AHEAD OF A PRE-FRONTAL TROUGH AND
   COLD FRONT ASSOCIATED WITH THE STRONG UPPER TROUGH.  A MOIST
   ENVIRONMENT WITH WEAK LAPSE RATES SHOULD LIMIT THE AMOUNT OF
   AVAILABLE INSTABILITY. HOWEVER...INCREASING MID-UPPER LEVEL WINDS
   FOR STRONG DEEP LAYER SHEAR AND 60 KT SLY LLJ MOVING EWD ACROSS THIS
   AREA TODAY WILL SUPPORT ORGANIZED STORMS IN THE FORM OF A LINEAR MCS
   WITH EMBEDDED SUPERCELLS.  DAMAGING WINDS AND TORNADOES WILL BE THE
   PRIMARY THREAT.  AN INCREASE IN SEVERE STORM COVERAGE/INTENSITY IS
   POSSIBLE LATER IN THE PERIOD AS THE COLD FRONT MERGES WITH THE
   PRE-FRONTAL TROUGH OVER AL INTO GA AFTER 19/06Z.  SEVERE ACTIVITY
   MAY MOVE INTO THE WRN CAROLINAS BY 12Z WEDNESDAY.
   
   ...ARKLATEX TO SERN MO SWD TO CENTRAL LA...
   COLD MID-LEVEL TEMPERATURES /-18C TO -20C AT 500 MB/ WITH THE SHORT
   WAVE TROUGH WILL SPREAD ACROSS ERN OK/NERN TX/AR/NRN LA DURING THE
   AFTERNOON...WHERE SOME SURFACE HEATING IS POSSIBLE WITH MODELS
   SUGGESTING A DRY INTRUSION SPREADING FROM SW-NE ACROSS THIS AREA. 
   THERMODYNAMIC PROFILES WILL BE FURTHER ENHANCED BY SURFACE DEWPOINTS
   IN THE LOWER 60S TO SUPPORT A NARROW AXIS OF MODERATE INSTABILITY
   /MLCAPE 1000-1500 J/KG/ IN ADVANCE OF THE COLD FRONT.  INCREASING
   LARGE SCALE ASCENT WITHIN LEFT EXIT REGION OF 120-130 KT 250 MB SWLY
   JET LOCATED ALONG THE NWRN GULF COAST TO LOWER MS VALLEY COMBINED
   WITH CONVERGENCE ALONG THE FRONT IN A MODERATELY UNSTABLE AIR MASS
   WILL RESULT IN CONVECTIVE INITIATION WITH SUSTAINED ROTATING
   UPDRAFTS LIKELY...GIVEN STRONG DEEP LAYER SHEAR.  STEEP LAPSE
   RATES...COLD MID-LEVEL TEMPERATURES AND FAIRLY LOW WET-BULB ZERO
   HEIGHTS WILL FAVOR PRIMARILY A THREAT FOR SEVERE HAIL. SEVERE
   THREAT ACROSS THIS AREA IS EXPECTED TO DIMINISH BY EARLY EVENING AS
   THE COLD FRONT MOVES EWD TO THE GULF COAST STATES.
   
   ...COASTAL SC...
   LOW-LEVEL MOISTURE WILL INCREASE TODAY ACROSS CAROLINAS AS SSELY
   LOW-LEVEL WINDS ADVECT ATLANTIC MOISTURE INLAND WITH UPPER 60S
   SURFACE DEWPOINTS EXPECTED ALONG COASTAL SC/SERN NC AFTER 00Z. 
   WSWLY MID-LEVEL WINDS WILL STRENGTHEN TO 50 KT BY THE END OF THE
   PERIOD WITH THE APPROACH OF A STRONG UPPER TROUGH ACROSS THE GULF
   COAST STATES.  SLY LLJ WILL INCREASE TO 40-45 KT ACROSS SC...AND
   COMBINED WITH SWLY MID-LEVEL WINDS DEEP LAYER SHEAR WILL SUPPORT
   SUPERCELLS...WHILE THE STRENGTH OF THE LLJ SHOULD FAVOR AN ISOLATED
   TORNADO THREAT TOWARD 12Z WEDNESDAY.
   
   ..PETERS/BOTHWELL.. 11/18/2003
   
   ...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 1 OUTLOOK IS SCHEDULED FOR 1300Z