000 FXUS66 KPQR 131647 AFDPQR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 830 AM PST WED DEC 13 2000 ANOTHER SERIES OF VERY COMPLICATED WEATHER PATTERNS AND SYSTEMS EXPECTED THROUGH THE WEEK. CURRENT SYSTEM MOVING SOUTHEAST SIMILAR TO THE SYSTEM THAT PRODUCED SNOW MONDAY. MAIN DIFFERENCE IS A LITTLE WARMER AIR ALOFT AND HIGHER DEWPOINTS IN EASTERLY GORGE FLOW. THIS HAS ALLOWED CENTRAL WILLAMETTE VALLEY TO MODERATE...AND AFTER SPOTTER CALLS WILL DROP ADVISORY WITH ZONE ISSUANCE. GORGE IS CLEARLY STILL GOING TO HAVE SNOW AND FREEZING RAIN THROUGH THE DAY AND INTO THE EVENING AS THE DEFORMATION ZONE WITH THIS SYSTEM STALLS AND THE EAST OUTFLOW CONTINUES...THEN SLOWLY DRIES OUT TONIGHT. THE NORTHERN WILLAMETTE VALLEY AND SOUTHWEST WASHINGTON AREAS ADJACENT TO THE GORGE AND COLUMBIA GORGE WILL STILL HAVE SOME FREEZING RAIN OR SNOW WELL INTO THE AFTERNOON...AND PLAN TO EXTEND THE ADVISORY THERE THROUGH THE AFTERNOON. AREAS ESPECIALLY IN THE SOUTHERN PART OF THE NORTHERN WILLAMETTE VALLEY MAY STAY MIXED OUT. WILL KEEP SOME PRECIPITATION INTO THE EVENING UNTIL DEFORMATION ZONE WEAKENS...THEN KEEP SCATTERED SHOWERS LATER TONIGHT AS A WEAK SHORT WAVE PASSES. MAJOR TRANSITION WILL FOLLOW WEDNESDAY AND WEDNESDAY NIGHT AS THE NEXT PACIFIC SYSTEM BLOWS THROUGH. OFFSHORE FLOW IN THE GORGE WILL INITIALLY ALLOW PRECIPITATION TO BE SNOW OR FREEZING RAIN...POSSIBLY EXTENDING TO AREAS AROUND THE WEST END OF THE GORGE...BUT STRONG CIRCULATION AND LOW WITH SYSTEM WILL ENSURE MOST AREAS ARE RAIN. WILL CONTINUE GORGE WINTER STORM WATCH. WILL SEE TRANSITION TO RAIN THROUGH GORGE BY FRIDAY MORNING AS THIS SYSTEM BLOWS THROUGH AND TURNS FLOW ONSHORE. THE WEDNESDAY AND WEDNESDAY NIGHT SYSTEM WILL USHER IN THE CHANGE TO MORE ONSHORE AND MILD AND WET PATTERN FOR THE REMAINDER OF THE FORECAST PERIOD. POSSIBLE GALE WITH THE WEDNESDAY NIGHT SYSTEM... WITH GALE OR STORM WARNING POSSIBLE AND HIGH WIND COAST FOR FRIDAY NIGHT AND SATURDAY SYSTEM. TOLLESON AST 76+ PDX 878 SLE 988 EUG 988 .PDX...WINTER WEATHER ADVISORY THIS MORNING FOR NORTH WILLAMETTE VALLEY...WEST COLUMBIA RIVER GORGE...AND THE LOWER # COLUMBIA ZONES. WINTER STORM WATCH WEST COLUMBIA RIVER GORGE THURSDAY AFTERNOON AND EVENING. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR.