AFDSEW AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SEATTLE WA 359 AM PDT MON MAR 11 2024 .SYNOPSIS...A FRONT WILL MOVE THROUGH WESTERN WASHINGTON TONIGHT. INCREASING RAIN AND WIND AHEAD OF THE FRONT THIS AFTERNOON. UPPER LEVEL TROUGH BEHIND THE FRONT TUESDAY WILL BE EAST OF THE CASCADES BY EARLY TUESDAY EVENING. UPPER LEVEL RIDGE BUILDING OFFSHORE WEDNESDAY NOSING INTO SOUTHERN BRITISH COLUMBIA WEDNESDAY NIGHT AND THURSDAY. THE RIDGE WILL SLOWLY MOVE EAST AND BE OVER WESTERN WASHINGTON FOR THE WEEKEND. && .SHORT TERM /TODAY THROUGH WEDNESDAY/...SATELLITE IMAGERY SHOWS MOSTLY CLOUDY SKIES OVER WESTERN WASHINGTON EARLY THIS MORNING. DOPPLER RADAR INDICATING A FEW SHOWERS OVER THE AREA ESPECIALLY WEST OF PUGET SOUND AND OVER THE CASCADES. TEMPERATURES AT 3 AM/10Z WERE IN THE LOWER TO MID 40S. SCATTERED SHOWERS CONTINUING THIS MORNING WITH WEST SOUTHWESTERLY FLOW ALOFT PROVIDING A LITTLE RAIN SHADOW FOR NORTHERN KING AND SNOHOMISH COUNTY. NEXT FRONT WELL OFFSHORE AT 10Z, NEAR 133W, WILL MOVE EAST TODAY WITH THE LEADING EDGE OF THE RAIN OUT AHEAD OF THE FRONT REACHING THE COAST MIDDAY AND THE INTERIOR DURING THE AFTERNOON. LIKE THE LAST TWO SYSTEMS WINDS PICKING UP AHEAD OF THE FRONT ALONG THE COAST AND OVER THE NORTH INTERIOR. WINDS STRONG ENOUGH ALONG THE COAST BY LATE AFTERNOON FOR A WIND ADVISORY. SNOW CONTINUING IN THE MOUNTAINS ABOVE 2500-3000 FEET. FLOW ALOFT BECOMING MORE SOUTHWESTERLY AS THE FRONT APPROACHES PUTTING THE HEAVIEST SNOW AMOUNTS AROUND MOUNT BAKER, 5 TO 10 INCHES. A SMALLER SNOW MAXIMUM AT MOUNT RAINIER WITH THE REMAINDER OF THE MOUNTAINS GETTING 1 TO 4 INCHES. HIGHS TODAY NEAR 50. FRONT REACHING THE COAST AROUND 06Z TONIGHT MOVING INTO THE CASCADES AROUND 12Z. WINDS PEAKING JUST AHEAD OF THE FRONT. WIND ADVISORY WILL BE ISSUED FOR THE NORTHWEST INTERIOR INCLUDING ADMIRALTY INLET UNTIL AFTER MIDNIGHT. WIND ADVISORY FOR THE COAST WILL CONTINUE THROUGH 06Z. BREEZY CONDITIONS ELSEWHERE. SNOW INCREASING IN THE MOUNTAINS. THE WARNING WILL REMAIN IN EFFECT FOR THE NORTH CASCADES WITH AN ADVISORY FOR THE REMAINDER OF THE MOUNTAINS. RAIN CHANGING TO SHOWERS BEHIND THE FRONT. POST FRONTAL INSTABILITY NOT VERY IMPRESSIVE BUT ENOUGH TO INCLUDE A SLIGHT CHANCE OF THUNDERSTORMS ALONG THE COAST BEHIND THE FRONT. LOWS NEAR 40. UPPER LEVEL TROUGH MOVING THROUGH WESTERN WASHINGTON TUESDAY KEEPING SHOWERS IN THE FORECAST. CONVERGENCE ZONE FORMING OVER SOUTHERN SKAGIT AND NORTHERN SNOHOMISH COUNTY IN THE AFTERNOON. SLIGHT CHANCE OF THUNDER IN THE CONVERGENCE ZONE AS WELL AS ALONG THE COAST IN THE MORNING BEFORE THE TROUGH AXIS PASSES BY TO THE EAST. SNOW LEVELS REMAINING AROUND 2500 FEET FOR MORE SNOW IN THE MOUNTAINS. HIGHEST AMOUNTS IN THE NORTH CASCADES AND NEAR STEVENS PASS WITH THE AFTERNOON CONVERGENCE ZONE, 5 TO 10 INCHES. UPPER LEVEL RIDGE BEGINNING TO BUILD WELL OFFSHORE TUESDAY NIGHT. A FEW SHOWERS STILL EMBEDDED IN THE NORTHWESTERLY FLOW ALOFT DECREASING AFTER MIDNIGHT. THE CONVERGENCE ZONE WILL ALSO DISSIPATE. LOWS IN THE MID 30S TO LOWER 40S. UPPER LEVEL RIDGE CONTINUING TO BUILD OFFSHORE WEDNESDAY WITH A WARM FRONT TRYING TO MOVE OVER THE TOP OF THE RIDGE. RIDGE STRONG ENOUGH TO PUSH MOST OF THE SYSTEM NORTH OF THE AREA WITH JUST A CHANCE OF SHOWERS ALONG THE COAST. HIGHS WEDNESDAY AGAIN NEAR 50. .LONG TERM /THURSDAY THROUGH SUNDAY/...EXTENDED MODELS AND ENSEMBLES CONTINUE TO SHOW GOOD CONSISTENCY WITH THE UPPER LEVEL RIDGE BUILDING INTO SOUTHERN BRITISH COLUMBIA WEDNESDAY NIGHT INTO THURSDAY. RIDGE SLOWLY DRIFTING EAST AND BY THE WEEKEND WILL BE OVER WESTERN WASHINGTON. LOW LEVEL FLOW TURNING OFFSHORE FRIDAY WILL REMAIN OFFSHORE SATURDAY BEFORE WEAKENING SUNDAY. THIS WILL MAKE SATURDAY THE WARMEST DAY FOR THE INTERIOR BUT BOTH DAYS ON THE WEEKEND WILL BE IN THE 60S FOR THE ENTIRE AREA WITH LOWER 70S POSSIBLE IN THE FOOTHILLS ESPECIALLY SATURDAY. WARMING TREND BEGINNING THURSDAY WITH HIGHS IN THE MID 50S WARMING TO NEAR 60 FRIDAY. EVEN WITH THE WEAKENING OFFSHORE FLOW LATE IN THE WEEKEND INTO MONDAY HIGHS MONDAY STILL IN THE UPPER 50S TO MID 60S. THIS WEEKEND INTO THE FIRST PART OF NEXT WEEK WILL BE THE WARMEST WEATHER SINCE OCTOBER 2023. FELTON && .AVIATION...SOUTHWEST FLOW ALOFT WILL INCREASE TODAY AS A VIGOROUS FRONT AND TRAILING UPPER TROUGH APPROACHES THE REGION. CEILINGS WILL LOWER TO MVFR ALONG THE COAST BY 18Z AS RAIN SPREADS ONSHORE. THESE CONDITIONS WILL SPREAD TO INTERIOR AREAS THIS AFTERNOON AND TONIGHT. SOUTHERLY SURFACE WINDS WILL INCREASE ACROSS THE REGION BY AFTERNOON...WITH GUSTS OF 25 TO 35 KNOTS BY LATE AFTERNOON INTO TONIGHT. KSEA...A MIX OF VFR AND MVFR CEILINGS IN SCATTERED SHOWERS WILL TRANSITION BACK TO STRATIFORM RAIN 18Z-20Z WITH CEILINGS LOWERING BACK TO SOLID MVFR AND PERSISTING INTO TONIGHT. SURFACE WINDS SOUTHERLY BACKING TO SOUTHEASTERLY AND INCREASING TO 15 TO 25 KNOTS THIS AFTERNOON AND EVENING. 27 && .MARINE...THE LAST OF A SERIES OF FRONTS WILL PUSH ONSHORE LATE TONIGHT. GALES ARE EXPECTED AHEAD OF THE FRONT OVER THE COASTAL WATERS AS WELL AS THE EAST ENTRANCE TO THE STRAIT AND ADJACENT WATERS. A POST-FRONTAL ONSHORE PUSH WILL KEEP SMALL CRAFT ADVISORY CONDITIONS GOING INTO TUESDAY. A SURFACE RIDGE WILL BUILD OVER THE COASTAL WATERS ON WEDNESDAY THEN SHIFT INLAND THURSDAY AND FRIDAY FOR OFFSHORE FLOW AND GENERALLY TRANQUIL CONDITIONS ACROSS AREA WATERS. COASTAL SEAS WILL REMAIN HAZARDOUS THROUGH MIDWEEK BEFORE SUBSIDING BELOW 10 FEET THURSDAY THROUGH THE UPCOMING WEEKEND. 27 && .HYDROLOGY...HEAVY RAIN OVER THE SOUTH SLOPES OF THE OLYMPICS THIS AFTERNOON THROUGH EARLY TUESDAY MORNING WILL LIKELY PUSH THE SKOKOMISH RIVER IN MASON COUNTY ABOVE FLOOD STAGE TONIGHT. A FLOOD WATCH REMAINS IN EFFECT FOR MASON COUNTY. OTHER RIVERS AROUND THE AREA RISING TONIGHT THROUGH TUESDAY BUT SNOW LEVELS BETWEEN 2500-3000 FEET WILL LIMIT THE RISES AND KEEP THE REMAINING RIVERS BELOW FLOOD STAGE. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...WIND ADVISORY FROM 6 PM THIS EVENING TO 2 AM PDT TUESDAY FOR ADMIRALTY INLET AREA-SAN JUAN COUNTY-WESTERN SKAGIT COUNTY- WESTERN WHATCOM COUNTY. FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS. WINTER WEATHER ADVISORY UNTIL 5 PM PDT TUESDAY FOR OLYMPICS. WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING FOR CENTRAL COAST-NORTH COAST. WINTER STORM WARNING UNTIL 11 PM PDT TUESDAY FOR WEST SLOPES NORTH CASCADES AND PASSES. WINTER WEATHER ADVISORY UNTIL 11 PM PDT TUESDAY FOR WEST SLOPES NORTH CENTRAL CASCADES AND PASSES. WINTER WEATHER ADVISORY UNTIL 11 PM PDT TUESDAY FOR WEST SLOPES SOUTH CENTRAL CASCADES AND PASSES. PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT TUESDAY FOR GRAYS HARBOR BAR. SMALL CRAFT ADVISORY UNTIL 5 PM PDT TUESDAY FOR PUGET SOUND AND HOOD CANAL-WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA. SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 PM PDT TUESDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA. GALE WARNING FROM 2 PM THIS AFTERNOON TO 5 AM PDT TUESDAY FOR ADMIRALTY INLET-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS. SMALL CRAFT ADVISORY UNTIL NOON PDT TODAY FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM- COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER OUT 10 NM. GALE WARNING FROM NOON TODAY TO 2 AM PDT TUESDAY FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM- COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM- COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER OUT 10 NM. &&