528
FXUS66 KSEW 081630
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 AM PST SAT MAR 8 2025
SYNOPSIS
UPPER LEVEL RIDGE TO THE EAST WITH MOIST SOUTHWESTERLY
FLOW ALOFT. WEAK ATMOSPHERIC RIVER EXTENDING FROM VANCOUVER ISLAND
SOUTHWEST BACK TO NEAR 35N/140W. THE RIVER WILL LIFT A LITTLE
NORTH LATER TODAY INTO TONIGHT THEN WEAKEN AND SAG SOUTH OVER THE
AREA SUNDAY. THIS FEATURE WILL DISSIPATE OVER THE PACIFIC
NORTHWEST SUNDAY NIGHT INTO MONDAY. A SERIES OF WEATHER SYSTEMS
WILL MOVE THROUGH WESTERN WASHINGTON BEGINNING TUESDAY WITH
ADDITIONAL SYSTEMS LATER WEDNESDAY AND FRIDAY.
SHORT TERM /TODAY THROUGH MONDAY/
CURRENT FORECASTS
LOOK ON TRACK AS A WARM FRONT LIFTS NORTHWARD ACROSS THE AREA TODAY
THEN TRAILING COLD FRONT STALLS OFFSHORE TONIGHT BEFORE EVENTUALLY
SHIFTING INLAND SUNDAY AFTERNOON. PREVIOUS DISCUSSION FOLLOWS. 27
SATELLITE IMAGERY SHOWS ATMOSPHERIC RIVER EXTENDING FROM VANCOUVER
ISLAND SOUTHWEST BACK TO NEAR 35N/140W. DOPPLER RADAR SHOWS RAIN
FROM ABOUT HOQUIAM TO EVERETT NORTHWARD. CLOUDY SKIES OVER THE
REMAINDER OF THE AREA. TEMPERATURES AT 3 AM/11Z WERE IN THE 40S.
WEAK ATMOSPHERIC RIVER WOBBLING AROUND OVER THE COAST AND NORTHERN
PORTIONS OF THE AREA THIS MORNING INTO THE AFTERNOON HOURS. UPPER
LEVEL TROUGH BACK BETWEEN 135-140W DIGGING SOUTH THIS AFTERNOON
WILL CHANGE THE ORIENTATION OF THE RIVER FROM SOUTHWEST TO
NORTHEAST TO A LITTLE MORE NORTH/SOUTH. THIS WILL PUSH THE RIVER A
LITTLE NORTH LOWERING THE RAIN CHANCES ACROSS ALL BUT THE NORTH
COAST AND NEAR THE CANADIAN BORDER LATER THIS AFTERNOON. WITH THE
FEATURE WOBBLING THIS MORNING WILL HAVE CHANCE POPS ALL THE WAY
DOWN TO LEWIS COUNTY BUT ANY PRECIPITATION FROM SEATTLE SOUTH WILL
BE LIGHT IF IT HAPPENS AT ALL. DIFFERENT STORY ALONG THE NORTH
COAST WITH RAIN ALL DAY. IVT VALUES NOT VERY IMPRESSIVE, 400-500
KG/M/SEC, BUT WITH RAIN ALL DAY AT LEAST AN INCH IN THE FORECAST.
MOST OF WESTERN WASHINGTON IN THE WARM SECTOR TODAY BUT CLOUD
COVER WILL KEEP HIGHS IN THE 50S FOR THE MOST PART. COULD SEE A 60
IN THE FOOTHILLS SOUTH OF I-90.
UPPER LEVEL TROUGH WELL OFFSHORE CONTINUING TO DIG SOUTH TONIGHT
STANDING THE ATMOSPHERIC RIVER UP EVEN MORE GIVING THE SOUTHEAST
PORTION OF THE FORECAST AREA DRY CONDITIONS AND JUST CHANCE POPS
FOR MOST OF THE REMAINDER OF THE AREA. THE EXCEPTION WILL BE
ALONG THE COAST, ESPECIALLY THE NORTH COAST WITH LIKELY OR HIGHER
POPS. CLOUD COVER PLUS BEING IN THE WARM SECTOR WILL MAKE FOR A
MILD NIGHT WITH LOWS MOSTLY IN THE MID 40S.
TROUGH OFFSHORE MOVING EAST SUNDAY SHIFTING THE WEAKENING
ATMOSPHERIC RIVER OVER THE AREA. RAIN IN THE MORNING OVER THE
NORTHERN PORTIONS SPREADING SOUTH LATE MORNING INTO THE
AFTERNOON. DECREASING MOISTURE LEVELS WITH THE FEATURE AS THE
SOUTHWESTERLY FLOW ALOFT OFFSHORE GETS CUT OFF BY THE UPPER LEVEL
LOW DEVELOPING OFF THE CALIFORNIA COAST. WE COULD USE SOME RAIN.
THE YEARLY RAINFALL TOTAL IN SEATTLE OF 5.63 INCHES THROUGH MARCH
7TH IS THE 6TH DRIEST TOTAL THROUGH MARCH 7TH IN 81 YEARS OF
RECORDS. HIGHS A LITTLE COOLER, IN THE LOWER TO MID 50S.
WHAT IS LEFT OF THE FEATURE SAGGING SOUTH INTO WESTERN OREGON
SUNDAY NIGHT DISSIPATING MONDAY MORNING. RAIN ENDING FIRST OVER
THE NORTHWEST INTERIOR WITH THE RAIN ENDING FROM NORTH TO SOUTH
SUNDAY NIGHT INTO EARLY MONDAY MORNING. NOT MUCH COLD AIR BEHIND
THE FEATURE LIMITING POST FRONTAL SHOWERS. LOWS IN THE MID 30S TO
LOWER 40S.
ZONAL FLOW ALOFT OVER WESTERN WASHINGTON MONDAY WITH THE NEXT
FRONT MOVING ACROSS THE EASTERN PACIFIC. MOST SOLUTIONS HAVE THE
FRONT CLOSE ENOUGH TO BRING RAIN BACK TO THE COAST AND OVER THE
NORTHWEST INTERIOR BY LATE IN THE DAY. JUST A CHANCE OF RAIN
ELSEWHERE. HIGHS NEAR 50.
LONG TERM /TUESDAY THROUGH FRIDAY/
EXTENDED MODELS IN GOOD
AGREEMENT WITH A WET PATTERN SETTING UP OVER WESTERN WASHINGTON.
A PAIR OF SYSTEMS MOVING THROUGH TUESDAY AND LATER WEDNESDAY. THE
WEDNESDAY SYSTEM HAS A DEEP 970 MB LOW NEAR 130W IN THE MORNING
BUT THE LOW CURVES NORTH NORTHEAST WEDNESDAY AFTERNOON. LOW STILL
CLOSE ENOUGH TO BRING WINDY CONDITIONS TO THE COAST AND POSSIBLY
THE NORTHWEST INTERIOR. UPPER LEVEL TROUGH THURSDAY KEEPING
PRECIPITATION IN THE FORECAST. ANOTHER FRONT REACHING THE AREA
FRIDAY. PARENT LOW WITH THIS FEATURE WELL UP INTO THE GULF OF
ALASKA MINIMIZING THE WIND THREAT. TEMPERATURES RUNNING A LITTLE
BELOW NORMAL THROUGH THE PERIOD. SNOW LEVELS BELOW THE PASSES WITH
A GOOD AMOUNT OF NEW SNOW FOR THE MOUNTAINS BY THE END OF THE
PERIOD. FELTON
AVIATION
INCREASING SOUTHWEST FLOW ALOFT AS A TROUGH LOOMS
OFFSHORE. VFR ACROSS MOST TERMINALS THIS MORNING EXCEPT FOR COASTAL
AIRFIELDS. KHQM AND KUIL MAY CONTINUE TO SEE MVFR CIGS AT TIMES AS
AN ATMOSPHERIC RIVER PROVIDES A GLANCING BLOW TO THE COAST AND
NORTHERN INTERIOR. VFR CIGS ARE TO MOSTLY REMAIN FOR INTERIOR
TERMINALS FOR THE MUCH OF THE TAF PERIOD BEFORE WIDESPREAD RAINFALL
TRACKS INTO W WA LATER ON SUNDAY. BREEZY SOUTHERLY WINDS ARE IN THE
FORECAST TODAY WITH GUSTS UP TO 20-25 KT FOR SITES SUCH AS KPAE,
KSEA, KOLM. KHQM AND KBLI COULD SEE GUSTS AS HIGH AS 30-35 KT.
KSEA...VFR THROUGHOUT MUCH OF THE PERIOD. S WINDS INCREASING TO 8 TO
12 KT TODAY WITH GUSTS NEAR 20-25 KT BEFORE DIMINISHING OVERNIGHT.
LOWER CIGS POSSIBLE INTO SUNDAY AS RAIN TRACKS TOWARDS THE AIRFIELD.
MCMILLIAN
MARINE
SURFACE HIGH NOW EAST OF THE CASCADES AS A FRONT LINGERS
OFFSHORE. SCA WINDS REMAIN OVER THE COASTAL WATERS, EAST ENTRANCE,
ADMIRALTY INLET, AND NORTHERN INLAND WATERS. WINDS WILL GRADUALLY
DECREASE INTO SUNDAY BUT SEAS ARE TO REMAIN ELEVATED. 10 TO 14 FEET
TODAY, REMAINING ABOVE 10 FEET THROUGH SUNDAY BEFORE DECREASING INTO
MONDAY-TUESDAY. ACTIVE WATER LIKELY INTO MIDWEEK, WHERE A DEVELOPING
LOW PRESSURE SYSTEM COULD BRING STRONGER WINDS AND ELEVATED SEAS TO
THE COASTAL WATERS.
MCMILLIAN
HYDROLOGY
RAIN TOTALS ALONG THE NORTH COAST AND IN THE OLYMPICS
IN THE 2.5 TO 4 INCH RANGE THIS WEEKEND. RIVERS FLOWING OFF THE
OLYMPICS RUNNING LOW THIS MORNING SO EVEN WITH THIS AMOUNT OF RAIN
ONLY THE SKOKOMISH RIVER IS FORECAST TO GET INTO ACTION STAGE.
NO RIVER FLOODING THE NEXT 7 DAYS FOR THE REMAINDER OF THE RIVERS.
FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 AM PST SUNDAY 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 5 PM PST SUNDAY 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.
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