090  
FXUS66 KSEW 281735  
AFDSEW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SEATTLE WA  
935 AM PST MON NOV 28 2022  
   
UPDATE
 
WHILE SOME SHOWERS REMAIN IN THE AREA THIS MORNING,  
CONDITIONS ARE DRYING OUT. THE WINTER STORM WARNING FOR THE  
CASCADES AND THE WINTER WEATHER ADVISORY FOR THE NORTH OLYMPIC  
PENINSULA WILL EXPIRE AT 10AM. LOOKING AHEAD THERE REMAINS A LOT  
OF UNCERTAINTY WITH THE FORECAST FOR TUESDAY-WEDNESDAY. LOWLAND  
SNOW IS EXPECTED, HOW MUCH IS THE QUESTION. WITH SOUTHERLY LOW  
LEVEL WINDS TEMPERATURES ARE EXPECTED TO BE WARM ENOUGH TO KEEP  
MOST OF PRECIPITATION IN THE FORM OF RAIN; PARTICULARLY FOR SOUTH  
OF PUGET SOUND AND ALONG THE COAST. FOR ALL OTHER AREAS,  
PRECIPITATION TYPE IS GOING TO BE VERY DEPENDENT ON PRECIPITATION  
RATES AS WELL AS HOW MUCH COLD AIR MOVES INTO THE AREA TODAY AND  
EARLY TOMORROW. CONDITIONS ARE GOING TO VARY THROUGHOUT THE  
REGION OVER THE COURSE OF THIS WEEK. MAKE SURE TO CHECK THE LATEST  
FORECAST BEFORE HEADING OUT.  
 
THE PREVIOUS FORECAST DISCUSSION WITH UPDATED AVIATION AND MARINE  
SECTION IS BELOW.  
 

 
   
PREV DISCUSSION
 
/ISSUED 455 AM PST MON NOV 28 2022/  
   
SYNOPSIS
 
ACTIVE WEATHER WILL CONTINUE ACROSS THE REGION  
THROUGH MUCH OF THE WEEK AHEAD. EXPECT CONTINUED SHOWERS TO  
MAINTAIN MOUNTAIN SNOW AND LOWLAND RAIN OR RAIN AND SNOW THIS  
MORNING. DRY BUT COOLER CONDITIONS DEVELOP LATE MONDAY THROUGH  
EARLY TUESDAY, BUT THE NEXT WEATHER SYSTEM QUICKLY APPROACHES.  
COOL AND UNSETTLED WEATHER CONTINUES LATE IN THE WEEK WITH  
ADDITIONAL CHANCES FOR LOWLAND SNOW AT TIMES AS ADDITIONAL  
DISTURBANCES CROSS THE REGION.  
 

 
   
SHORT TERM /TODAY THROUGH WEDNESDAY/
 
PLENTY OF SHOWERS  
REMAINING IN THE CASCADES AND ACROSS THE NORTHERN PORTIONS OF  
PUGET SOUND THIS MORNING. THE WINTER STORM WARNING FOR THE  
CASCADES (FROM SNOHOMISH THROUGH LEWIS COUNTIES) CONTINUES WITH A  
FEW MORE INCHES OF SNOW EXPECTED TODAY. MEANWHILE, SOME SHOWERS  
ACROSS WHIDBEY ISLAND AND EAST THROUGH THE I-5 CORRIDOR FROM  
WHATCOM THROUGH SNOHOMISH COUNTIES MAY OCCASIONALLY CONTAIN SOME  
LIGHT SNOW OR A RAIN/SNOW MIX OVER THE LOWLANDS, BUT GIVEN THE  
RELATIVELY WEAK PRECIPITATION RATES AND TEMPERATURES HOLDING A FEW  
DEGREES ABOVE MODEL GUIDANCE, HAVE ELECTED TO CANCEL THE ADVISORY  
FOR WHATCOM/SKAGIT/SNOHOMISH COUNTIES. CONFIDENCE REMAINS LOWER  
ALONG THE EASTERN STRAIT OF JUAN DE FUCA, ESPECIALLY THROUGH THE  
SEQUIM TO PORT ANGELES CORRIDOR. WHILE THE EXPECTED FRASER OUTFLOW  
HAS BEEN SLOW TO MATERIALIZE, THIS IS EXPECTED TO STILL DEVELOP  
WITH THE POTENTIAL FOR SOME UPSLOPE ENHANCEMENT ACROSS THE  
NORTHERN OLYMPIC PENINSULA. OTHERWISE, WE'LL SEE SHOWERS DIMINISH  
FROM NORTH TO SOUTH THROUGH THE DAY, AND A DRY AFTERNOON FOR MOST.  
 
THE NEXT WEATHER SYSTEM WILL THEN QUICKLY APPROACH THE AREA ON  
TUESDAY, WITH THE LEADING PRECIPITATION EXPECTED TO REACH THE  
OLYMPIC PENINSULA BY EARLY AFTERNOON. WITH COOLER AIR IN PLACE,  
ESPECIALLY IF THE CURRENT TIMING HOLDS TRUE, EXPECT TO SEE SOME  
LIGHT SNOW TO FALL AT ONSET WITH THE MOISTURE RUNNING AHEAD OF THE  
APPROACHING WARM FRONT. SOUTHERLY LOW-LEVEL WINDS SHOULD BRING A  
SLIGHT BUMP IN SNOW LEVELS AND PRECLUDE MUCH IN THE WAY OF SNOW  
ACCUMULATIONS SOUTH OF AROUND TACOMA. MEANWHILE, CONFIDENCE IS  
LOWER FOR AROUND SEATTLE, WHERE THE TIMING OF THE WARM SOUTHERLY  
FLOW ARRIVING AND THE MOISTURE LEADS TO A SOMEWHAT TRICKY  
FORECAST WHERE A FEW DEGREES IN THE TEMPERATURE PROFILE IS ALL THE  
DIFFERENCE BETWEEN A FEW INCHES OF ACCUMULATING SNOW AND A COLD 35  
DEGREE RAIN. THE MOST LIKELY SCENARIO FOR ACCUMULATING LOWLAND  
SNOW DURING THIS TIME WOULD BE DURING PERIODS OF HEAVIER  
PRECIPITATION, WHERE ENOUGH COLD AIR IS DRAGGED DOWN TO THE  
SURFACE. SNOW LEVELS ARE THEN EXPECTED TO DROP BACK DOWN BELOW  
1000 FEET BY WEDNESDAY AFTERNOON. WITH COLDER AIR FILTERING IN  
WEDNESDAY THE THREAT OF ACCUMULATING LOWLAND SNOW INCREASES AND  
WILL REMAIN.  
 
ONE ADDITIONAL NOTE WITH WINDS INCREASING AHEAD OF THE COLD FRONT  
LATE TUESDAY NIGHT INTO EARLY WEDNESDAY. WHILE NO HEADLINES HAVE  
BEEN ISSUED YET, GUIDANCE CONTINUES TO TREND UPWARD WITH RESPECT  
TO WINDS INCREASING. GUSTS UP TO 55 MPH ARE POSSIBLE THROUGH THE  
SAN JUANS AND ADMIRALTY INLET AREAS, WHILE THE WINDY SPOTS IN  
WHATCOM AND SKAGIT COUNTIES MAY SEE GUSTS TO NEAR 45 MPH.  
 
MEANWHILE, CONFIDENCE IS HIGHER THAT ANOTHER ROUND OF  
HEAVY SNOW WILL COME TO THE OLYMPICS AND CASCADES LATE TUESDAY  
THROUGH WEDNESDAY OR PERHAPS EVEN THROUGH THURSDAY.  
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
EXPECT AN UNSETTLED  
WEATHER PATTERN TO REMAIN FOR MUCH OF THE SECOND HALF OF THE WEEK  
WITH BELOW NORMAL TEMPERATURES RETURNING. WITH ADDITIONAL ROUNDS  
OF MOISTURE ROTATING THROUGH, THERE WILL LIKELY BE ADDITIONAL  
SHOWERS THAT BRING THE POTENTIAL FOR SNOW FLURRIES DOWN IN THE  
LOWLANDS. THIS NEXT ONE WEDNESDAY NIGHT INTO THURSDAY LOOKS TO BE  
MERELY LIGHT SNOW SHOWERS, BUT AGAIN PLENTY OF DETAILS YET TO BE  
WORKED OUT SO FOR NOW THE KEY MESSAGE IS TO REMAIN AWARE OF THE  
POSSIBILITY. THE OTHER MAIN POINT HERE IS THAT TEMPERATURES LOOK  
TO REMAIN QUITE COLD THROUGH THE WEEK AHEAD WITH LOWS IN THE 20S  
AND HIGHS ONLY TOPPING IN THE MID TO 30S ON THURSDAY ACROSS THE  
INTERIOR. BELOW NORMAL TEMPERATURES THEN LIKELY TO CONTINUE LATE  
IN THE WEEK, AND WITH SNOW LEVELS REMAINING LOW, WILL NEED TO  
CLOSELY MONITOR THE POTENTIAL FOR SNOW TO AGAIN FALL IN THE  
LOWLANDS AT SOME POINT.  
 

 
   
AVIATION
 
UPPER TROUGHING IS MOVING ACROSS THE PACIFIC NORTHWEST  
THIS MORNING WITH NORTHWESTERLY FLOW. ANY LINGERING MVFR  
DECKS WILL IMPROVE TO VFR THROUGH THE REST OF THE MORNING WITH  
CLEARING. SHOWERS WILL TAPER OFF LATE MORNING FOR MOST AREAS.  
INCREASING FRASER RIVER OUTFLOW WINDS AT KBLI TODAY WITH MAINLY  
NORTHERLY WINDS.  
 
KSEA...ANY CHANCE FOR MVFR CEILINGS IS DECREASING THROUGH THE REST  
OF THE MORNING. BY NOON, HIGH CONFIDENCE IN VFR CRITERIA AS CLOUDS  
SCATTER. NORTHERLY WINDS FOR THE REMAINDER OF THE DAY BEFORE  
SHIFTING TOWARDS THE SOUTH LATER TONIGHT INTO TUESDAY MORNING.  
 
MCMILLIAN  
 

 
   
MARINE
 
THE FLOW WILL TRANSITION OFFSHORE AND STRENGTHEN THROUGH  
THE DAY. GUSTY FRASER OUTFLOW WINDS TODAY FOR THE NORTHERN INLAND  
WATERS WITH A GALE WARNING IN PLACE. SMALL CRAFT ADVISORY WINDS ARE  
IN EFFECT FOR ALL WATERS THROUGH THIS MORNING FOR THE INCREASING  
NORTH/EAST OFFSHORE WINDS. OFFSHORE WINDS WILL TAPER  
OFF THIS EVENING AND INTO TONIGHT. A RATHER BRIEF PERIOD OF LIGHT  
WINDS IS EXPECTED TUESDAY MORNING. A STRONG WEATHER SYSTEM WILL MOVE  
THROUGH TUESDAY EVENING AND WEDNESDAY FOR INCREASING  
SOUTH/SOUTHEASTERLY WINDS ACROSS THE AREA. GALES ARE LIKELY FOR THE  
COASTAL WATERS DURING THIS TIME PERIOD, AS WELL AS THE NORTHERN  
INLAND WATERS, PUGET SOUND, EASTERN STRAIT OF JUAN DE FUCA, AND  
ADMIRALTY INLET. IN ADDITION, THERE IS A CHANCE FOR STORM FORCE  
WINDS GUSTS ACROSS THE EASTERN STRAIT OF JUAN DE FUCA TUESDAY NIGHT  
INTO WEDNESDAY MORNING. WINDS WILL TAPER A BIT WEDNESDAY AFTERNOON  
FOR ADDITIONAL SMALL CRAFT ADVISORY WINDS. OFFSHORE WINDS INCREASE  
WEDNESDAY NIGHT AND INTO THURSDAY.  
 
SEAS OF 10 TO 13 FT WILL SUBSIDE TONIGHT INTO TUESDAY MORNING TO 7  
TO 9 FEET. SEAS WILL BUILD WEDNESDAY TO 13 TO 17 FT SUBSIDING  
THURSDAY INTO THURSDAY NIGHT. JD  
 

 
   
HYDROLOGY
 
NO RIVER FLOODING IS EXPECTED THROUGH THE NEXT SEVEN  
DAYS.  
 

 
   
SEW WATCHES/WARNINGS/ADVISORIES
 
 
WA...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR SAN JUAN COUNTY-  
WESTERN WHATCOM COUNTY.  
 
WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR  
ADMIRALTY INLET AREA-EASTERN STRAIT OF JUAN DE FUCA.  
 
WINTER STORM WARNING UNTIL 10 AM PST THIS MORNING FOR WEST  
SLOPES NORTH CENTRAL CASCADES AND PASSES-WEST SLOPES SOUTH  
CENTRAL CASCADES AND PASSES.  
 
PZ...SMALL CRAFT ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR GRAYS  
HARBOR BAR.  
 
SMALL CRAFT ADVISORY UNTIL 10 AM PST THIS MORNING FOR WEST  
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.  
 
SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR ADMIRALTY  
INLET-CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-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-EAST ENTRANCE U.S. WATERS  
STRAIT OF JUAN DE FUCA-PUGET SOUND AND HOOD CANAL.  
 
GALE WARNING UNTIL 10 PM PST THIS EVENING FOR NORTHERN INLAND  
WATERS INCLUDING THE SAN JUAN ISLANDS.  
 

 
 

 
 
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