FXUS66 KSEW 311518
 AFDSEW
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SEATTLE WA
 830 AM PDT SAT JUL 31 2010
 
 .SYNOPSIS...SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THE MOUNTAINS 
 TODAY AS AN UPPER LEVEL TROUGH SHIFTS INLAND. ANOTHER TROUGH WILL 
 PASS THROUGH WESTERN WASHINGTON ON SUNDAY WITH THUNDERSTORMS MAINLY 
 AFFECTING THE NORTH CASCADES. LOW LEVEL ONSHORE FLOW WILL CONTINUE 
 THROUGH NEXT WEEK WITH TEMPERATURES NEAR NORMAL. 
 
 &&
 
 .SHORT TERM...MARINE LAYER IS DEEPER THIS MORNING THOUGH LESS 
 EXTENSIVE AS WHATCOM COUNTY IS LARGELY IN THE CLEAR. EXPECT BURNOFF 
 TIME TO BE A LITTLE LATER THAN YESTERDAY...CLOSER TO 20Z. HIGH 
 TEMPERATURES WILL BE CORRESPONDINGLY A FEW DEGREES LOWER THAN 
 YESTERDAY...LOW 70S INLAND AND STILL AROUND 60 ON THE COAST. 
 THUNDERSTORMS REMAIN A POSSIBILITY IN THE MOUNTAINS TODAY AND 
 TONIGHT AS A WEAK UPPER TROUGH IS CAMPED RIGHT OVER WESTERN 
 WASHINGTON.
 
 ANOTHER TROUGH SETS UP OVER THE AREA ON SUNDAY. THIS COULD ALSO 
 TRIGGER A FEW THUNDERSTORMS OVER THE MOUNTAINS. CURRENTLY THE 
 FORECAST HAS THEM ONLY OVER THE NORTH CASCADES SO MAY HAVE TO GET 
 KPDT ON BOARD WITH THIS IDEA AND ADD THEM TO THE CENTRAL CASCADES. 
 ANOTHER TROUGH DROPS FROM THE NORTH MONDAY NIGHT AND HEIGHTS LOWER A 
 BIT. THIS IS NOT REALLY REFLECTED IN MOS TEMPS WHICH SHOW A SLOW 
 WARMING TREND THROUGH ABOUT TUESDAY. UPSHOT IS FEW SIGNIFICANT 
 CHANGES WILL BE MADE TO THE FORECAST THIS AFTERNOON. BURKE
 
 .LONG TERM...PREVIOUS DISCUSSION...NO SIGNIFICANT ADJUSTMENTS MADE 
 TO THE LONG TERM FORECAST. THE PAC NW STILL LIES UNDER AN UPPER 
 LEVEL TROUGH THROUGH MUCH OF THE PERIOD. BOTH THE GFS AND EURO SHOW 
 A SHARPER...MORE DEFINED TROUGH AXIS CROSSING W WA MIDWEEK...BUT 
 EXACT TIMING IS STILL A LITTLE MUDDLED. WITH HIGH PRES ANCHORED OVER 
 THE NE PAC...SURFACE FLOW REMAINS ONSHORE WITH TYPICAL LATE NIGHT 
 AND MORNING CLOUDS...WITH SOME CLEARING IN THE AFTERNOON. TEMPS WILL 
 STAY PRETTY CLOSE TO NORMAL. 33
 
 &&
 
 .AVIATION...UPPER LOW OVER NW OREGON COAST AT 15Z WILL MOVE OVER 
 SOUTH WA CASCADES THIS AFTERNOON AND THEN TO NE WA SUNDAY MORNING. 
 AT THE SURFACE...HIGH PRESSURE WILL REMAIN OFFSHORE WITH LOWER 
 PRESSURE INLAND. AIR MOIST AT LOW LEVELS WITH MOISTURE BURNING BACK 
 TO THE COAST AFTER 18Z. AIR STABLE EXCEPT UNSTABLE OVER THE 
 CASCADES. SCHNEIDER
 
 STRATUS A LITTLE DEEPER TODAY COMPARED TO YESTERDAY. THEREFORE 
 EXPECT A LITTLE LATER BURN OFF TODAY...19Z-22Z. COAST SHOULD STAY 
 SOCKED IN. STRATUS PUSHING BACK INTO THE INTERIOR AGAIN TONIGHT 
 AFTER MIDNIGHT. SCHNEIDER
 
 KSEA...SW WIND 4-8 KT. LOW CLOUDS AND FOG BEGINNING TO LIFT AROUND 
 18Z AND STRATUS BURNING OFF AROUND 21Z. SCHNEIDER
 
 &&
 
 .MARINE...TYPICAL SUMMERTIME ONSHORE PATTERN WITH DAILY SCA WEST 
 WINDS EXPECTED CENTRAL/EAST STRAIT LATE THIS AFTERNOON THROUGH EARLY 
 SUNDAY MORNING. LITTLE CHANGE IN THE NEXT FIVE DAYS. SCHNEIDER
 
 &&
 
 .SEW WATCHES/WARNINGS/ADVISORIES...
 WA...NONE. 
 PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT.
 
 
 
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