• Seattle, Washington, United States (98101)
  • WxZone: WAZ508ICAO: KBFILat: 47.61NLon: 122.33W

Discussions

300 PM PDT SUN AUG 29 2010

.SYNOPSIS...A WEATHER SYSTEM WILL REACH THE AREA OVERNIGHT...MOST OF 
THE MOISTURE WITH THIS SYSTEM IS DIRECTED TOWARD THE SOUTH COAST AND 
INTO NORTHWEST OREGON. A WETTER WEATHER SYSTEM WILL ARRIVE TUESDAY. 
PRECIPITATION MAY CONTINUE INTO WEDNESDAY WITH A POSSIBLE THIRD 
WEATHER SYSTEM. AN UPPER RIDGE WILL BUILD FOR A COUPLE OF DRY SUNNY 
DAYS THURSDAY AND FRIDAY BEFORE ANOTHER TROUGH ARRIVES NEXT WEEKEND.

&&

.SHORT TERM...THE WEATHER SYSTEM JUST OFFSHORE SHOWS UP PRETTY GOOD 
IN THE SATELLITE IMAGE THIS AFTERNOON...THIS SYSTEM WILL CONTINUE TO 
SLIDE SOUTHEAST SO THAT EARLY MONDAY MORNING RAIN IS LIKELY FOR THE 
COAST...ESPECIALLY SOUTH COAST...AND AROUND DAYBREAK THERE SHOULD BE 
AREAS OF RAIN OVER WESTERN OREGON AND SOUTH OF ABOUT OLYMPIA. AS THE 
SYSTEM PASSES BY THE SURFACE GRADIENTS WILL TURN ONSHORE AGAIN...AND 
THERE WILL STILL BE A CHANCE OF SHOWERS THRU MON AFTERNOON AND 
EVENING...MAINLY IN THE CASCADES. THE NEXT SYSTEM ON TAP FOR TUESDAY 
IS ESPECIALLY WET IN THE 18Z NAM...WITH PERHAPS AN INCH OF RAIN 
ALONG THE COAST AND A QUARTER TO A HALF INCH OF RAIN FOR THE WRN WA 
INTERIOR. WEDNESDAY CONTINUES TO BE A TRICKY DAY TO FIGURE OUT...THE 
NAM HAS A SYSTEM IN THE ZONAL FLOW OF A DIRTY RIDGE BUT THE GFS 
LOOKS MUCH MORE LIKE JUST A WEAK WARM FRONT BRUSHING BY AS THE RIDGE 
BEGINS TO BUILD...I HEDGED THE FCST AND SAID SCATTERED SHOWERS...IT 
MAY TURN OUT TO BE AREA OF RAIN CONTINUE INTO WEDNESDAY...OR PERHAPS 
FADE TO DRIZZLE. 19

.LONG TERM...A COUPLE DAYS OF RIDGE FINALLY LOOK LIKE A GOOD BET THU 
AND FRI SO I HAVE PUSHED THE FCSTS TO SUNNY AND ADDED A FEW DEGREES 
TO THE HIGHS...DON'T YET WANT TO GET CARRIED AWAY BECAUSE THIS IS 
THE FIRST MODEL RUN WHERE THERE IS AGREEMENT ON THAT. THE RIDGE WILL 
PROBABLY GIVE OUT BY NEXT WEEKEND BUT AT LEAST THE THE GFS AND EURO 
MATCH UP FOR THU AND FRI NOW. 500MB HEIGHTS PEAK ABOVE THE 582DAM 
COUNTER BY THU NITE AND AN UPPER TROF IS JUST OUT SIDE OF 140W AT 
THAT TIME...BOTH THE 12Z GLOBAL MODELS HAVE THAT WORKING OVER THE 
PACNW BY NEXT SUNDAY...SO THE TAIL END OF THE FCST WILL PROBABLY 
NEED TO TURN COOL AND SHOWERY AGAIN...BUT FOR NOW CLIMO TEMPS AND 
LOW POPS ARE IN THE FCST FOR NEXT WEEKEND. 19

&&

.AVIATION...UPPER LEVEL LOW PRES WILL REMAIN ANCHORED OVER THE PAC 
NW THROUGH TONIGHT...THEN SHIFT SLIGHTLY EWD ON MON. LIGHT SW FLOW 
ALOFT WILL BECOME LIGHT NLY ON MON. A WEAK SURFACE LOW WILL TRACK SE 
OFF THE WA COAST TONIGHT INTO OREGON ON MON. THE ATMOSPHERE WILL BE 
SOMEWHAT UNSTABLE THROUGH EARLY THIS EVENING...OTHERWISE STABLE AND 
GENERALLY MOIST. 

KSEA...SW WIND 8-13 KT W/ GUSTS TO 18 KT...EASING TO 4-7 KT AFTER 
04Z.

&&

.MARINE...A 1006 MB SURFACE LOW WILL TRACK SE THROUGH THE WA OUTER 
COASTAL WATERS TONIGHT. SLY WINDS HAVE PICKED UP THIS AFTERNOON NEAR 
THE WA COAST...STRONGER THAN MODELS FORECAST. DECIDED TO ISSUE A 
SMALL CRAFT FOR ALL THE COASTAL WATERS LATER THIS EVENING THROUGH 
MON MORNING. THE W ENTRANCE MAY REACH CLOSE TO SMALL CRAFT BUT WILL 
KEEP WINDS LIMITED TO 20 KT FOR NOW. A STRONGER FRONT WILL ARRIVE 
LATE MON NIGHT AND TUE WITH SCA WINDS LIKELY FOR THE COAST...AND 
POSSIBLY THE E ENTRANCE. POST FRONTAL WLY SC WINDS ARE POSSIBLE 
THROUGH THE STRAIT.

&& 

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY WA COASTAL WATERS LATE THIS EVENING        
     THROUGH MON MORNING.

$$

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