SPC AC 280557
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1157 PM CST MON DEC 27 2004
   
   VALID 281200Z - 291200Z
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 WSW EKA 45 ENE UKI
   20 SSE SCK 50 SSE FAT 25 E NID 40 NW IGM 20 NNE FLG 25 S INW 55 WNW
   SAD 25 SW FHU.
   
   ...NO SVR TSTM AREAS FORECAST...
   
   ...SYNOPSIS...
   MODELS TEND TO AGREE IN THE EVOLUTION OF THE OVERALL UPPER PATTERN
   FOR THE DAY 1 PERIOD WITH THE CLOSED UPPER LOW OFF THE WEST COAST
   DE-AMPLIFYING TODAY AND THEN MOVING INLAND TONIGHT AS AN OPEN WAVE. 
   THIS OCCURS AS AN UPSTREAM TROUGH OVER THE GULF OF AK DIGS SEWD
   TOWARD THE PAC NW/NRN CA REGION.  HOWEVER...ETA/GFS/ECMWF DIFFER IN
   THE STRENGTH OF THE UPPER TROUGH AS IT MOVES INLAND TONIGHT AND THE
   MOVEMENT OF THE SURFACE LOW.  THE GFS IS DEEPER WITH THE UPPER
   TROUGH AND FASTER WITH THE SURFACE LOW WHICH IS EXPECTED TO BE OVER
   EAST CENTRAL CA BY THE END OF PERIOD.  THE SLOWER ETA/ECMWF PLACE
   THE SURFACE LOW JUST OFFSHORE OF POINT CONCEPTION BY 12Z WEDNESDAY.
   
   ...SRN CA...
   DESPITE THESE MODEL DIFFERENCES...THERE IS AGREEMENT THAT ONE SHORT
   WAVE TROUGH /CURRENTLY LOCATED AT 30.5N/127.7W PER SATELLITE
   IMAGERY/ WILL MOVE INLAND ACROSS SRN CA BY LATE THIS MORNING...WITH
   A SECOND SHORT WAVE TROUGH REACHING SRN CA BY 12Z WEDNESDAY. 
   CURRENT OCEANIC LIGHTNING DATA SHOWED NUMEROUS STRIKES WITH THE LEAD
   SHORT WAVE TROUGH.
   
   EXTENSIVE AREA OF CLOUDS WITH ONGOING PRECIPITATION WILL BE OVER SRN
   CA AT THE START OF THE PERIOD...GIVEN STRONG LARGE SCALE ASCENT OVER
   THIS AREA AHEAD OF THE LEAD SHORT WAVE TROUGH. THESE CLOUDS/
   PRECIPITATION ARE EXPECTED TO MINIMIZE AIR MASS DESTABILIZATION
   INLAND...WHILE THE STRONGEST INSTABILITY SHOULD REMAIN JUST OFFSHORE
   AS A COLD POOL STEEPENS LAPSE RATES BY LATE MORNING.  THUS...GIVEN
   STRONG DEEP LAYER SHEAR...ANY SEVERE THREAT SHOULD REMAIN OFFSHORE.
   A GREATER POTENTIAL...ALTHOUGH ALSO SMALL..FOR SEVERE STORMS TO MOVE
   INLAND ALONG THE SRN CA COAST WILL BE TONIGHT AS THE MAIN STRONGER
   UPPER TROUGH APPROACHES THIS AREA.  NONETHELESS...AS LOW-LEVEL WINDS
   BACK IN ADVANCE OF EACH UPPER TROUGH...LOW-LEVEL SHEAR WILL INCREASE
   SUPPORTING A THREAT FOR ISOLATED WATERSPOUTS OFF THE COAST OF SRN
   CA.
   
   ELSEWHERE...AS PLUME OF STEEP LAPSE RATES AND LARGE SCALE ASCENT
   SPREADS FARTHER INLAND TOWARD THE FOUR CORNERS REGION AHEAD OF THE
   MID-LEVEL TROUGH...THE POTENTIAL FOR THUNDERSTORMS IS EXPECTED TO
   DEVELOP EWD INTO AZ.
   
   ..PETERS.. 12/28/2004
   
   ...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 BY 1300Z