Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 292253
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
355 PM PDT SAT AUG 29 2015

.SYNOPSIS...A STRONG WEATHER SYSTEM MOVED THROUGH THE REGION TODAY.
ADDITIONAL WEAKER FRONTS WILL REACH THE AREA THROUGH THE MIDDLE OF
NEXT WEEK AS A LARGE UPPER LEVEL TROUGH TAKES UP RESIDENCE OVER THE
REGION. HIGH PRESSURE WILL PROBABLY BUILD OVER THE AREA NEXT WEEKEND.

&&

.SHORT TERM...THE LOW PRESSURE SYSTEM THAT WAS CENTERED JUST OFF THE
COAST THIS MORNING HAS MOVED NORTH INTO BRITISH COLUMBIA AND THE
PRESSURE GRADIENT OVER WESTERN WA WILL CONTINUE TO DECREASE THROUGH
THIS EVENING. THE ASTORIA TO FORKS PRESSURE GRADIENT PEAKED AT JUST
UNDER 10 MB AT 11 AM THIS MORNING AND THE OLYMPIA TO BELLINGHAM
PRESSURE GRADIENT PEAKED AT 7 MB EARLY THIS AFTERNOON. ADDITIONAL
FRONTAL WAVES WILL GIVE PERIODS OF RAIN OR SHOWERS THROUGH THE
MIDDLE OF NEXT WEEK AS A FALL LIKE UPPER TROUGH SETTLES OVER THE AREA.

.LONG TERM...SHORTWAVES WILL CONTINUE TO ROTATE THROUGH THE AREA IN
THE MEAN UPPER LEVEL TROUGH THROUGH FRIDAY WITH A GOOD CHANCE OF SHOWERS.
THE COOLEST AIR ALOFT WORKS OVER THE AREA BY ABOUT WED NIGHT WHEN THE
SNOW LEVEL MIGHT BE AROUND 5000FT IN THE NORTH CASCADES. A RIDGE AND
WARMER AIR WILL LIKELY BUILD OVER THE AREA FOR NEXT WEEKEND.

&&

.AVIATION...THE STRONG SURFACE LOW THAT MOVED NORTH ALONG
THE WASHINGTON COAST HAS MOVED INTO BRITISH COLUMBIA JUST NORTH OF
VANCOUVER ISLAND. STRONG SOUTHERLY WINDS HAVE BEGUN TO WEAKEN
SOMEWHAT OVER THE SOUTH...BUT STILL REMAIN RELATIVELY STRONG AND
GUSTY ALL AREAS. CEILINGS REMAIN VFR MOST AREAS THIS AFTERNOON. A
SECONDARY FRONT JUST MOVING ONSHORE AT 22Z/3PM PDT WILL BRING
ANOTHER ROUND OF RAIN FOLLOWED BY SHOWERS TO THE INTERIOR. EXPECT
CEILINGS TO FALL TO MVFR LEVELS AS THIS BAND OF RAINFALL WORKS
THROUGH THE INTERIOR OVER THE NEXT FEW HOURS...FOLLOWED BY
IMPROVEMENT TO VFR LEVELS THROUGH THE REMAINDER OF THE EVENING.
WINDS WILL CONTINUE TO EASE AS THE SURFACE LOW CONTINUES TO FALL
APART OVER BRITISH COLUMBIA. ABUNDANT LOW LEVEL MOISTURE AND
LINGERING SHOWERS WILL LIKELY HELP CEILINGS DROP TO MVFR OR NEAR
MVFR LEVEL THROUGH THE AREA EARLY SUNDAY MORNING...WITH GRADUAL
IMPROVEMENT DURING THE MORNING ON SUNDAY. THE ATMOSPHERE WILL REMAIN
MOIST AND GENERALLY STABLE OVERNIGHT WITH STRONG SOUTHWESTERLY FLOW
ALOFT BECOMING MODERATE OVER NIGHT.

KSEA...VFR CONDITIONS WILL LOWER TO MVFR AS A FRONTAL BAND OF RAIN
WORKS INTO THE INTERIOR BY AROUND O1Z...THEN IMPROVE TO VFR LEVELS
BEHIND THE BAND THROUGH THE REMAINDER OF THE EVENING. SOUTHWESTERLY
WINDS 20 KT GUSTING TO 30 KT WILL EASE WITH THE RAIN. WINDS WILL
REMAIN SW 10 TO 12 KT...THEN EASE FURTHER AFTER MIDNIGHT.

&&

.MARINE...THE STRONG SURFACE LOW THAT MOVED NORTH THROUGH THE
COASTAL WATERS OF WASHINGTON THIS AFTERNOON HAS MOVED INTO BRITISH
COLUMBIA NORTH OF VANCOUVER ISLAND. SURFACE PRESSURE GRADIENTS HAVE
RELAXED SOMEWHAT...BUT SILL REMAIN STRONG. THE STORM WARNING FOR THE
COASTAL WATERS WILL REMAIN IN EFFECT UNTIL 6 PM THIS EVENING...AND
THE NORTHERN INLAND WATERS UNTIL 5 PM. A BRIEF SURGE OF WESTERLIES
HAS BROUGHT GALE WINDS TO THE CENTRAL STRAIT...HAVE ISSUED A GALE
WARNING FOR THIS EVENING TO REFLECT THIS. EXPECT WINDS TO EASE OVER
ALL WATERS AS SURFACE GRADIENTS CONTINUE TO RELAX TONIGHT. EXPECT
LINGERING SMALL CRAFT ADVISORY SOUTHERLY WINDS...20 TO 30 KT...AND
SEAS TO PERSIST OVER THE COASTAL WATERS...NORTHERN INLAND
WATERS...EAST STRAIT...ADMIRALTY INLET...AND PUGET SOUND/HOOD CANAL
THIS EVENING. A SECONDARY FRONT MOVING THROUGH THE COASTAL WATERS
LATE THIS AFTERNOON WILL WORK INLAND...BRINGING RAIN TO ALL WATERS
THIS EVENING AND PERHAPS A SHORT LIVED BURST IN WINDS.

AN ADDITIONAL SET OF WEAKER SYSTEMS WILL MOVE THROUGH THE WATERS
MONDAY AND TUESDAY STRENGTHENING SOUTHWESTERLY AND SOUTHERLY WINDS
MAINLY FOR THE COASTAL WATERS BUT ALSO SOME OF THE INTERIOR WATERS.

&&

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...HIGH WIND WARNINGS ARE IN EFFECT FOR MUCH OF THE LOWLANDS
 FROM 8 AM THIS MORNING TIL 6 PM PDT THIS EVENING.

PZ...STORM WARNING IN EFFECT THROUGH 6 PM FOR THE COASTAL WATERS.

     STORM WARNING IN EFFECT THROUGH 5 PM FOR THE NORTHERN INLAND
     WATERS.

     GALE WARNINGS IN EFFECT THROUGH 5 PM FOR THE EAST
     STRAIT...ADMIRALTY INLET...AND PUGET SOUND/HOOD CANAL.

     GALE WARNING IN EFFECT THROUGH MIDNIGHT FOR THE CENTRAL STRAIT.

     SMALL CRAFT ADVISORY IN EFFECT FROM 6 PM THROUGH MIDNIGHT FOR
     THE COASTAL WATERS.

     SMALL CRAFT ADVISORY IN EFFECT FROM 5 PM THROUGH MIDNIGHT FOR
     THE NORTHERN INLAND WATERS...EAST STRAIT...ADMIRALTY
     INLET...AND PUGET SOUND/HOOD CANAL.

&&

$$

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