SPC AC 181611
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1111 AM CDT SAT SEP 18 2004
   
   VALID 181630Z - 191200Z
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 N GGW 65 NE BIL 30
   NW WRL 40 NE RWL 20 NNE LAR 25 NW COS 20 E RTN 50 NE 4CR 35 SSE ELP
   ...CONT... 20 W CZZ 30 NNE RAL 55 ESE U31 15 W EKO 55 NNE WMC 25 NE
   RBL 50 SSW EKA.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 N DRT 35 ENE BGS
   60 SSE CDS 35 NNE MWL 10 SSE TYR 35 SE LCH.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 ESE HSI 45 ENE SUX
   10 SSE STC 40 WSW IWD 30 ENE AUW 20 N MMO 15 NNE STL 50 ESE TBN 20
   SSW UMN 15 WSW EMP 40 ESE HSI.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 NW FMY 10 N VRB.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 S WAL 25 SSE BWI
   15 ENE ABE 30 S RUT 10 S PWM.
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...ERN LONG ISLAND/EXTREME SERN NEW ENGLAND...
   SURFACE LOW ASSOCIATED WITH THE REMNANTS OF IVAN IS LOCATED OVER THE
   DELMARVA PENINSULA AND CONTINUES TO MOVE EWD TOWARD THE ATLANTIC. 
   FRONTAL BOUNDARY EXTENDING NEWD FROM THE LOW IS ACROSS ERN LONG
   ISLAND AND EXTREME SERN MA.  THIS FEATURE IS SLOWLY SAGGING SEWD AS
   SURFACE PRESSURES RISE ACROSS THE INTERIOR NORTHEAST.  ENHANCED LOW
   LEVEL SHEAR/HELICITY IS CO-LOCATED WITH THE BOUNDARY...AND POTENTIAL
   EXISTS FOR AN ISOLATED SUPERCELL TO DEVELOP WITHIN THIS ZONE AS A
   BAND OF CONVECTIVE CELLS MOVE NWD FROM THE ATLANTIC INTO SRN NEW
   ENGLAND.  A BRIEF TORNADO OR STRONG WIND GUST WILL BE POSSIBLE ALONG
   THIS BAND INTO THE AFTERNOON AS IT MOVES EWD...WITH THE THREAT
   ENDING BY 00Z AS THE ENTIRE SYSTEM GRADUALLY MOVES OFFSHORE.  
   
   ...SWRN UT INTO LOWER CO RIVER VALLEY AREA...
   WATER VAPOR SATELLITE IMAGERY AND GOES SOUNDER DATA INDICATE
   MOISTURE PLUME FROM JAVIER IS SPREADING NWD OVER PARTS OF THE
   SOUTHWEST...WITHIN STRENGTHENING DEEP LAYER SWLY FLOW IN ADVANCE OF
   STRONG UPPER TROUGH MOVING INLAND OVER THE PACIFIC NORTHWEST. 
   ENHANCED DIURNAL HEATING IS EXPECTED WITHIN A CORRIDOR FROM SERN
   CA/WRN AZ ACROSS SERN NV INTO UT WHERE CLOUDS ARE LIMITED.  THIS
   WILL RESULT IN DESTABILIZATION WITH MLCAPE OF 500-1000 J/KG LATER
   THIS AFTERNOON AND EVENING.  ETA/GFS AND SREF OUTPUT ALL INDICATE 
   THUNDERSTORMS WILL DEVELOP AND INCREASE LATE THIS AFTERNOON AND
   EVENING FROM SERN CA AND WRN AZ...SPREADING NWD ACROSS EXTREME SERN
   NV/SWRN UT AND NRN AZ TONIGHT AS UPPER DIVERGENCE IN ADVANCE OF
   UPPER TROUGH INCREASES OVER THE SRN PLATEAU REGION. DEEP LAYER SHEAR
   OF 30-40 KT WILL AID CONVECTIVE ORGANIZATION AND SUGGESTS POTENTIAL
   FOR A FEW STORMS TO PRODUCE STRONG WIND GUSTS AND POSSIBLE HAIL. 
   GIVEN THE INTERACTION OF TROPICAL MOISTURE WITH AN APPROACHING MID
   LATITUDE TROUGH...WE WILL CONTINUE TO MONITOR THIS REGION FOR SEVERE
   POTENTIAL IN LATER OUTLOOKS.
   
   ...UPPER MS VALLEY...
   CURRENT THUNDERSTORM SYSTEM OVER MO/ERN KS IS EXPECTED TO CONTINUE
   WEAKENING AS THE UPPER RIDGE BUILDS ACROSS THE PLAINS AND LOWER MO
   RIVER VALLEY.  THE NOCTURNAL LOW LEVEL JET IS FORECAST TO REDEVELOP
   OVER THE CENTRAL/NRN PLAINS TONIGHT WITH STRONG WARM ADVECTION
   PATTERN EXTENDING FROM THE NRN PLAINS INTO THE UPPER MS VALLEY.
   MODELS INDICATE A CAP WILL PERSIST OVER THE PLAINS...WITH A BETTER
   POSSIBILITY OF ELEVATED THUNDERSTORM DEVELOPMENT ALONG THE ERN EDGE
   OF THE CAP AFTER 06Z FROM SERN MN/WRN WI SWD INTO ERN IA/NWRN IL. 
   FORECAST SOUNDINGS SHOW MUCAPE OF 1000-1500 J/KG SUGGESTING THREAT
   FOR MARGINAL HAIL WITH A FEW LATE PERIOD STORMS.
   
   ..WEISS/CROSBIE.. 09/18/2004
   
   ...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 1 OUTLOOK IS SCHEDULED FOR 2000Z