194  
FXUS66 KSEW 260248  
AFDSEW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SEATTLE WA  
747 PM PDT MON MAR 25 2019  
   
UPDATE
 
WIDESPREAD RAIN CONTINUES TO MOVE ACROSS THE REGION THIS  
EVENING. THE FORECAST IS IN GOOD SHAPE AT THE MOMENT AND NO  
IMMEDIATE UPDATES ARE NEEDED. -WOLCOTT-  

 
   
SYNOPSIS
 
A WEAKENING FRONT WILL THROUGH THE AREA THIS EVENING  
WITH RAIN CHANGING TO SHOWERS. POST FRONTAL SHOWERS WILL END ON  
TUESDAY. A SECOND SYSTEM WILL CLIP THE SOUTHERN PART OF THE AREA  
ON WEDNESDAY. AN UPPER LEVEL LOW OFF THE OREGON COAST THURSDAY  
WILL DISSIPATE FRIDAY. THE NEXT SYSTEM WILL ARRIVE LATE NEXT  
WEEKEND.  
 

 
   
SHORT TERM /TONIGHT THROUGH THURSDAY/
 
A FRONT WILL PUSH NORTH  
THROUGH THE AREA THIS EVENING. AREAS OF LIGHT RAIN WILL CHANGE TO  
SPOTTY SHOWERS TONIGHT AS THE FRONT PUSHES NORTH INTO CANADA.  
THERE MIGHT BE AN ISOLATED THUNDERSTORM OFF THE CENTRAL COAST  
BEHIND THE FRONT TONIGHT WHERE IT WILL BE A BIT UNSTABLE BUT THE  
THREAT LOOKS TOO LOW TO MENTION IN THE FORECAST.  
 
ISOLATED TO SCATTERED SHOWERS WILL LINGER BEHIND THE FRONT INTO  
TUESDAY, ESPECIALLY OVER THE MOUNTAINS. SHOWERS SHOULD PRETTY MUCH  
END ENTIRELY TUESDAY EVENING AS WEAK HIGH PRESSURE ALOFT MOVES  
OVERHEAD. MOST OF THE AREA IS LOOKING DRY ON WEDNESDAY AS WELL.  
 
DIFLUENT SOUTHERLY FLOW ALOFT AHEAD OF AN UPPER LOW OFF THE OREGON  
COAST WILL BRING A THREAT OF SHOWERS TO AREAS SOUTH OF SEATTLE  
LATER WEDNESDAY. THE CHANCE OF SHOWERS WILL EXPAND TO MOST OF  
WESTERN WASHINGTON WEDNESDAY NIGHT AND THURSDAY AS THE UPPER LOW  
OFFSHORE OREGON SLOWLY APPROACHES THE COAST. TEMPERATURES WILL BE  
NEAR NORMAL THROUGH THE PERIOD. SCHNEIDER  
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
A WEAK UPPER TROUGH WILL  
LINGER OVER THE AREA FRIDAY AND POSSIBLY INTO SATURDAY WITH SOME  
WRAP AROUND MOISTURE AND INSTABILITY FOR A SLIGHT CHANCE OF  
SHOWERS. THERE MIGHT BE A DRY 12-24 HOUR PERIOD LATER SATURDAY  
INTO SUNDAY BUT IT'S HARD TO COMPLETELY RULE OUT A FEW SHOWERS FOR  
NOW GIVEN THE UNCERTAINTY AND SPREAD IN THE LONG RANGE MODELS. IT  
LOOKS A BIT WETTER SUNDAY NIGHT AND MONDAY AS A PACIFIC WEATHER  
SYSTEM REACHES THE AREA BUT NOTHING OUT OF THE ORDINARY FOR THIS  
TIME OF YEAR. SCHNEIDER  
 

 
   
AVIATION
 
RAIN WILL CONTINUE TO SPREAD ACROSS THE REGION THIS  
EVENING, BECOMING SHOWERY IN NATURE TUESDAY MORNING. CIGS WILL VARY  
FROM VFR TO MVFR AT TIMES OVERNIGHT INTO TUESDAY MORNING IN MANY  
LOCATIONS. CIGS WILL BEGIN TO BREAK UP DURING THE DAY TUESDAY.  
GENERALLY LIGHT SOUTHERLY OR VARIABLE WINDS ARE EXPECTED AHEAD OF  
THE FRONT, WITH INCREASING SOUTHERLY FLOW FOLLOWING THE FRONT WITH A  
BRIEF PERIOD OF SUSTAINED WINDS 15-20 KTS AND GUSTS NEAR 25 KTS  
POSSIBLE. WINDS WILL DECREASE THROUGH THE DAY TUESDAY.  
 
KSEA...MVFR CONDITIONS THROUGH THIS EVENING. RAIN WILL BECOME SPOTTY  
IN NATURE FOLLOWING 05Z. MVFR CIGS APPEAR LIKELY OVERNIGHT INTO  
TUESDAY FOLLOWING THE FRONT, GRADUALLY BREAKING UP BY LATE MORNING.  
LIGHT SOUTHERLY WINDS WILL INCREASE FROM THE S/SW WITH THE FRONT  
BETWEEN 05-06Z THIS EVENING, WINDS ARE MOST LIKELY TO PEAK AT 15-20  
KTS WITH GUSTS TO AROUND 25 KTS BEFORE SETTLING TO 10-15 KTS THROUGH  
THE REMAINDER OF THE NIGHT AND DECREASING FURTHER DURING THE  
AFTERNOON.  
-WOLCOTT-  
 

 
   
MARINE
 
ONSHORE WINDS WILL CONTINUE THROUGH TONIGHT AS A FRONTAL  
SYSTEM PUSHES THROUGH THE AREA AND AN AREA OF LOW PRESSURE LINGERS  
OFF THE COAST. SMALL CRAFT WINDS WILL DIMINISH FOR THE STRAIT  
DURING THE EVENING HOURS AND CONTINUE FOR THE COASTAL WATERS  
THROUGH TONIGHT. WINDS WILL TRANSITION TO SOUTHERLY THIS EVENING  
ALONG THE INTERIOR WATERS, WITH SMALL CRAFT WINDS INTO TUESDAY.  
WINDS WILL LIKELY TURN OFFSHORE TUESDAY NIGHT INTO WEDNESDAY WITH  
AN AREA OF LOW PRESSURE LOCATED OFF OF THE OREGON COAST. JD  
 

 
   
HYDROLOGY
 
RIVER FLOODING IS NOT EXPECTED FOR THE NEXT 7 DAYS.  
 

 
   
SEW WATCHES/WARNINGS/ADVISORIES
 
 
WA...NONE.  
PZ...SMALL CRAFT ADVISORY UNTIL 5 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.  
 
SMALL CRAFT ADVISORY UNTIL 2 PM PDT TUESDAY FOR ADMIRALTY INLET-  
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN  
INLAND WATERS INCLUDING THE SAN JUAN ISLANDS-PUGET SOUND  
AND HOOD CANAL.  
 

 
 

 
 
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