616 FXUS66 KPQR 041548 AFDPQR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 900 AM PDT WED SEP 4 2002 .SYNOPSIS...AN UPPER LOW OFF THE WASHINGTON COAST WILL REMAIN OFFSHORE AND DIG SOUTH THROUGH THURSDAY. DRY SOUTHWEST FLOW ALOFT WILL COVER AREA TODAY. THE UPPER FLOW WILL TURN A LITTLE MORE SOUTHERLY THURSDAY ALLOWING FOR MORE INSTABILITY OVER CASCADES. LOW APPROACHES SOUTH OREGON COAST FRIDAY WITH THE FLOW BECOMING MORE SOUTHERLY...GIVING THE BEST INSTABILITY TO AREA. THE LOW WILL SINK FARTHER SOUTH SATURDAY CONFINING THE SOUTHERLY FLOW AND INSTABILITY TO THE SOUTHERN MOUNTAINS. THE LOW STARTS TO MOVE INLAND SUNDAY WITH INSTABILITY REMAINING OVER SOUTHERN MOUNTAINS. .DISCUSSION... .SHORT TERM...LAST NIGHT/S AND THIS MORNING/S MODELS HAVE TAKEN A BIT FARTHER WEST TRACK ON THE UPPER LOW OFFSHORE MOVING SOUTH...WITH DRIER AND MORE STABLE CONDITIONS OVER OUR FORECAST AREA TODAY. MODEL SOUNDINGS CONFIRM A DRIER AND CAPPED SOUNDING THIS AFTERNOON. THUS MORE SUNSHINE AND MID 70S TEMPS INLAND TODAY. ONE EXCEPTION WILL BE PROXIMITY OF WEAK VORTICITY LOBE TRIGGERING CONVECTION OFF THE WASHINGTON COAST THAT MAY CLIP OUR FAR NORTH COASTAL ZONES THIS AFTERNOON AND EARLY EVENING. THE MODELS STILL START TO DESTABILIZE THE AIR MASS OVER OUR FORECAST AREA THURSDAY AS THE UPPER FLOW TURNS MORE SOUTHERLY AND UPPER TEMPS COOL. THIS STILL COULD BE OVERDONE. FOR NOW WILL STILL GO WITH ISOLATED MOUNTAIN CONVECTION THURSDAY AFTERNOON. WITH A SIGNIFICANT CHUNK OF THE LOW LIFTING TO THE NORTHEAST THURSDAY NIGHT AND FRIDAY...THIS APPEARS TO BE THE BEST CONVECTIVE PERIOD FOR NOW PER CURRENT FORECAST. A PIECE OF THE LOW STILL HANGS BACK TO THE SOUTH AND MOVES INLAND INTO CALIFORNIA THIS WEEKEND...WITH DRYING MOST OF OUR FORECAST AREA FROM THE NORTH...BUT A CHANCE OF CONVECTION IN OUR SOUTHERN MOUNTAINS. NO MARINE ADVISORIES WITH RELATIVELY LIGHT WINDS AND SWELLS. .LONG TERM...LONGER RANGE MODELS IN REASONABLE AGREEMENT...WITH DRYING THIS WEEKEND AS THE SOUTHERN PART OF THE LOW MOVES EAST TO OUR SOUTH. SATURDAY WILL BE THE IFFY DAY ABOUT WHETHER ANY OF FRIDAY/S WEATHER LINGERS IN TO SATURDAY. MODELS ARE SHOWING A FRONT MAY CLIP US MONDAY AND TUESDAY AND WILL ADDRESS THIS IN THE AFTERNOON PACKAGE. TOLLESON AST 22111 PDX 00113 SLE 00113 EUG 00113 .PQR...NONE.