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000
FXUS66 KSEW 020350
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
850 PM PDT MON SEP 1 2014

.SYNOPSIS...A VIGOROUS FAST MOVING FRONTAL SYSTEM WILL BRING A
LITTLE RAIN TO WESTERN WASHINGTON ON TUESDAY. A CONVERGENCE ZONE
WILL FORM OVER PUGET SOUND BEHIND THE FRONT LATE TUESDAY AFTERNOON
AND EVENING. DRY NORTH FLOW ALOFT WILL BRING SUNNY WEATHER BY
WEDNESDAY AFTERNOON. AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION
THURSDAY FOR SUNSHINE AND A WARMING TREND THAT WILL LAST INTO NEXT
WEEKEND.

&&

.SHORT TERM...PARTLY TO MOSTLY CLOUDY SKIES OVER W WA THIS EVENING.
WITH NO PRECIP ON RADAR THE DRY FORECAST FOR TONIGHT LOOKS GOOD.

WATER VAPOR IMAGERY SHOWED A VIGOROUS UPPER LEVEL TROUGH OVER THE AK
PANHANDLE AT 03Z. MODELS REMAIN IN GOOD AGREEMENT IN BRINGING THE
TROUGH SE ALONG THE B.C. COAST TONIGHT...THEN DOWN OVER W WA TUE
AFTERNOON. SATELLITE IMAGERY SHOWS THE FRONT HAS NOT QUITE FORMED
YET BUT MODELS INDICATE THAT FRONTOGENESIS WILL OCCUR TONIGHT AS THE
TROUGH APPROACHES. GFS/NAM/ECMWF AGREE ON BRINGING THE FRONT DOWN TO
TOFINO (CYAZ) AT 18Z/11 AM AND THEN JUST E OF PUGET SOUND AT 00Z/5
PM. THE FRONT WILL BE NARROW AND THE SYSTEM FAST MOVING SO THIS
SHOULD BE A QUICK SHOT OF RAIN...STARTING ON THE N COAST JUST AHEAD
OF THE FRONT AROUND 18Z. MODELS SHOW A CONVERGENCE ZONE PATTERN
SETTING UP OVER PUGET SOUND BEHIND THE FRONT TUESDAY EVENING. MODELS
ALSO SHOW A SHOT OF RAIN OVER THE N HALF OF THE INTERIOR AND THE N
CASCADES TUESDAY EVENING AS THE UPPER LEVEL TROUGH AXIS MOVES
THROUGH.

MODELS ARE ALL OVER THE PLACE WITH PRECIP AMOUNTS. THE 18Z NAM
SHOWED VERY LITTLE OVER THE LOWLANDS OUTSIDE OF 0.2 TO 0.3 IN THE
CONVERGENCE ZONE. THE 00Z NAM DISCARDS THE CONVERGENCE ZONE AND ONLY
HAS A FEW HUNDREDTHS OVER THE LOWLANDS. THE 18Z GFS IS SIMILAR TO
THE 18Z NAM. THE 12Z ECMWF HAS 0.5 TO AN INCH OVER THE N HALF OF W
WA. ALL THE MODELS HIT THE N CASCADES WITH 0.5 TO AN INCH. THE
CURRENT FORECAST IS MORE REASONABLE WITH ABOUT A TENTH OF AN INCH
FROM PUGET SOUND NORTHWARD. QPF OVER THE CASCADES COULD PROBABLY BE
DOUBLED TO AT LEAST A HALF INCH...ASSUMING A DECENT HIT FROM THE
UPPER TROUGH AXIS TUESDAY NIGHT.

COLD AIR ALOFT TRAILING THE UPPER LEVEL TROUGH WILL LOWER SNOW
LEVELS DOWN TO A LITTLE ABOVE 6000 FEET LATE TUESDAY NIGHT OVER THE
NORTH AND CENTRAL CASCADES. BUT PRECIP WILL BE MOSTLY OVER BY THEN
SO AT BEST THERE MAY BE UP TO AN INCH OF SNOW OVER THE N CASCADES.

PRECIP WILL BE OVER FOR THE LOWLANDS BY LATE TUESDAY NIGHT...BUT
INCREASING SW ONSHORE FLOW AHEAD OF THE FRONT WILL ENSURE THAT THE
LOWER AIR MASS REMAINS MOIST THROUGH WEDNESDAY MORNING. RAPID DRYING
ALOFT BEHIND THE TROUGH WILL HELP SKIES CLEAR OUT FOR SUNNY
CONDITIONS WEDNESDAY AFTERNOON. THE AIR MASS WILL REMAIN COOL SO
HIGHS WILL ONLY WARM UP A LITTLE TO AROUND 70.

AN UPPER LEVEL RIDGE OFFSHORE WILL BUILD E OVER THE REGION ON
THURSDAY. ONSHORE FLOW WEDNESDAY NIGHT WILL BE NEGLIGIBLE OR EVEN
WEAKLY OFFSHORE...SO WITH A WARMING AIR MASS THURSDAY AND LITTLE OR
NO MORNING STRATUS TO GET IN THE WAY...MAX TEMPS WILL WARM INTO THE
LOWER 70S N TO UPPER 70S SW INTERIOR. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 3 PM AFD...FRIDAY AND
SATURDAY LOOK LIKE THE WARMEST DAYS OF THE WEEK WITH HIGH PRESSURE
ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO WEAKEN ON SATURDAY BUT
THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON TEMPERATURES OR CLOUD
COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LOW LEVEL ONSHORE FLOW CONTINUES ACROSS WESTERN WA
TONIGHT. LOW CLOUDS WILL FILL IN BY MORNING WITH MVFR CONDITIONS
EXPECTED. A COLD FRONT WILL BRING RAIN TO THE COAST AND NORTH
INTERIOR TUE MORNING...WITH SHOWERS SPREADING INTO THE INTERIOR
DURING THE AFTERNOON. THE TRAILING UPPER LEVEL TROUGH WILL BRING
MORE SHOWERS TO THE INTERIOR AND CASCADES TUE NIGHT. 33

KSEA...LOW CLOUDS DEVELOPING OVERNIGHT WITH MVFR CONDITIONS
EXPECTED. SURFACE WINDS ARE LIGHT NORTHERLY...BUT WILL FLIP BACK TO
SOUTHERLY BY 18Z TUE. EXPECT SHOWERS IN THE VICINITY TUE AFTERNOON
AND EVENING. 33

&&

.MARINE...ONSHORE FLOW WILL CONTINUE ACROSS WESTERN WA TONIGHT - A
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE CENTRAL/EAST STRAIT
OF JUAN DE FUCA. ONSHORE FLOW WILL INCREASE BEHIND A COLD FRONT TUE
AFTERNOON WITH GALE FORCE WINDS POSSIBLE OVER THE COASTAL WATERS AND
THROUGH THE STRAIT. ONSHORE FLOW WILL EASE LATE TUE NIGHT. HIGH PRES
OVER THE NE PAC WILL MAINTAIN ONSHORE FLOW THROUGH WED. NORTHERLY
FLOW WILL PREVAIL THU AND FRI AS LOW PRES FORMS ALONG THE COAST. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML














000
FXUS66 KSEW 020350
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
850 PM PDT MON SEP 1 2014

.SYNOPSIS...A VIGOROUS FAST MOVING FRONTAL SYSTEM WILL BRING A
LITTLE RAIN TO WESTERN WASHINGTON ON TUESDAY. A CONVERGENCE ZONE
WILL FORM OVER PUGET SOUND BEHIND THE FRONT LATE TUESDAY AFTERNOON
AND EVENING. DRY NORTH FLOW ALOFT WILL BRING SUNNY WEATHER BY
WEDNESDAY AFTERNOON. AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION
THURSDAY FOR SUNSHINE AND A WARMING TREND THAT WILL LAST INTO NEXT
WEEKEND.

&&

.SHORT TERM...PARTLY TO MOSTLY CLOUDY SKIES OVER W WA THIS EVENING.
WITH NO PRECIP ON RADAR THE DRY FORECAST FOR TONIGHT LOOKS GOOD.

WATER VAPOR IMAGERY SHOWED A VIGOROUS UPPER LEVEL TROUGH OVER THE AK
PANHANDLE AT 03Z. MODELS REMAIN IN GOOD AGREEMENT IN BRINGING THE
TROUGH SE ALONG THE B.C. COAST TONIGHT...THEN DOWN OVER W WA TUE
AFTERNOON. SATELLITE IMAGERY SHOWS THE FRONT HAS NOT QUITE FORMED
YET BUT MODELS INDICATE THAT FRONTOGENESIS WILL OCCUR TONIGHT AS THE
TROUGH APPROACHES. GFS/NAM/ECMWF AGREE ON BRINGING THE FRONT DOWN TO
TOFINO (CYAZ) AT 18Z/11 AM AND THEN JUST E OF PUGET SOUND AT 00Z/5
PM. THE FRONT WILL BE NARROW AND THE SYSTEM FAST MOVING SO THIS
SHOULD BE A QUICK SHOT OF RAIN...STARTING ON THE N COAST JUST AHEAD
OF THE FRONT AROUND 18Z. MODELS SHOW A CONVERGENCE ZONE PATTERN
SETTING UP OVER PUGET SOUND BEHIND THE FRONT TUESDAY EVENING. MODELS
ALSO SHOW A SHOT OF RAIN OVER THE N HALF OF THE INTERIOR AND THE N
CASCADES TUESDAY EVENING AS THE UPPER LEVEL TROUGH AXIS MOVES
THROUGH.

MODELS ARE ALL OVER THE PLACE WITH PRECIP AMOUNTS. THE 18Z NAM
SHOWED VERY LITTLE OVER THE LOWLANDS OUTSIDE OF 0.2 TO 0.3 IN THE
CONVERGENCE ZONE. THE 00Z NAM DISCARDS THE CONVERGENCE ZONE AND ONLY
HAS A FEW HUNDREDTHS OVER THE LOWLANDS. THE 18Z GFS IS SIMILAR TO
THE 18Z NAM. THE 12Z ECMWF HAS 0.5 TO AN INCH OVER THE N HALF OF W
WA. ALL THE MODELS HIT THE N CASCADES WITH 0.5 TO AN INCH. THE
CURRENT FORECAST IS MORE REASONABLE WITH ABOUT A TENTH OF AN INCH
FROM PUGET SOUND NORTHWARD. QPF OVER THE CASCADES COULD PROBABLY BE
DOUBLED TO AT LEAST A HALF INCH...ASSUMING A DECENT HIT FROM THE
UPPER TROUGH AXIS TUESDAY NIGHT.

COLD AIR ALOFT TRAILING THE UPPER LEVEL TROUGH WILL LOWER SNOW
LEVELS DOWN TO A LITTLE ABOVE 6000 FEET LATE TUESDAY NIGHT OVER THE
NORTH AND CENTRAL CASCADES. BUT PRECIP WILL BE MOSTLY OVER BY THEN
SO AT BEST THERE MAY BE UP TO AN INCH OF SNOW OVER THE N CASCADES.

PRECIP WILL BE OVER FOR THE LOWLANDS BY LATE TUESDAY NIGHT...BUT
INCREASING SW ONSHORE FLOW AHEAD OF THE FRONT WILL ENSURE THAT THE
LOWER AIR MASS REMAINS MOIST THROUGH WEDNESDAY MORNING. RAPID DRYING
ALOFT BEHIND THE TROUGH WILL HELP SKIES CLEAR OUT FOR SUNNY
CONDITIONS WEDNESDAY AFTERNOON. THE AIR MASS WILL REMAIN COOL SO
HIGHS WILL ONLY WARM UP A LITTLE TO AROUND 70.

AN UPPER LEVEL RIDGE OFFSHORE WILL BUILD E OVER THE REGION ON
THURSDAY. ONSHORE FLOW WEDNESDAY NIGHT WILL BE NEGLIGIBLE OR EVEN
WEAKLY OFFSHORE...SO WITH A WARMING AIR MASS THURSDAY AND LITTLE OR
NO MORNING STRATUS TO GET IN THE WAY...MAX TEMPS WILL WARM INTO THE
LOWER 70S N TO UPPER 70S SW INTERIOR. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 3 PM AFD...FRIDAY AND
SATURDAY LOOK LIKE THE WARMEST DAYS OF THE WEEK WITH HIGH PRESSURE
ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO WEAKEN ON SATURDAY BUT
THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON TEMPERATURES OR CLOUD
COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LOW LEVEL ONSHORE FLOW CONTINUES ACROSS WESTERN WA
TONIGHT. LOW CLOUDS WILL FILL IN BY MORNING WITH MVFR CONDITIONS
EXPECTED. A COLD FRONT WILL BRING RAIN TO THE COAST AND NORTH
INTERIOR TUE MORNING...WITH SHOWERS SPREADING INTO THE INTERIOR
DURING THE AFTERNOON. THE TRAILING UPPER LEVEL TROUGH WILL BRING
MORE SHOWERS TO THE INTERIOR AND CASCADES TUE NIGHT. 33

KSEA...LOW CLOUDS DEVELOPING OVERNIGHT WITH MVFR CONDITIONS
EXPECTED. SURFACE WINDS ARE LIGHT NORTHERLY...BUT WILL FLIP BACK TO
SOUTHERLY BY 18Z TUE. EXPECT SHOWERS IN THE VICINITY TUE AFTERNOON
AND EVENING. 33

&&

.MARINE...ONSHORE FLOW WILL CONTINUE ACROSS WESTERN WA TONIGHT - A
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE CENTRAL/EAST STRAIT
OF JUAN DE FUCA. ONSHORE FLOW WILL INCREASE BEHIND A COLD FRONT TUE
AFTERNOON WITH GALE FORCE WINDS POSSIBLE OVER THE COASTAL WATERS AND
THROUGH THE STRAIT. ONSHORE FLOW WILL EASE LATE TUE NIGHT. HIGH PRES
OVER THE NE PAC WILL MAINTAIN ONSHORE FLOW THROUGH WED. NORTHERLY
FLOW WILL PREVAIL THU AND FRI AS LOW PRES FORMS ALONG THE COAST. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML















000
FXUS66 KSEW 020350
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
850 PM PDT MON SEP 1 2014

.SYNOPSIS...A VIGOROUS FAST MOVING FRONTAL SYSTEM WILL BRING A
LITTLE RAIN TO WESTERN WASHINGTON ON TUESDAY. A CONVERGENCE ZONE
WILL FORM OVER PUGET SOUND BEHIND THE FRONT LATE TUESDAY AFTERNOON
AND EVENING. DRY NORTH FLOW ALOFT WILL BRING SUNNY WEATHER BY
WEDNESDAY AFTERNOON. AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION
THURSDAY FOR SUNSHINE AND A WARMING TREND THAT WILL LAST INTO NEXT
WEEKEND.

&&

.SHORT TERM...PARTLY TO MOSTLY CLOUDY SKIES OVER W WA THIS EVENING.
WITH NO PRECIP ON RADAR THE DRY FORECAST FOR TONIGHT LOOKS GOOD.

WATER VAPOR IMAGERY SHOWED A VIGOROUS UPPER LEVEL TROUGH OVER THE AK
PANHANDLE AT 03Z. MODELS REMAIN IN GOOD AGREEMENT IN BRINGING THE
TROUGH SE ALONG THE B.C. COAST TONIGHT...THEN DOWN OVER W WA TUE
AFTERNOON. SATELLITE IMAGERY SHOWS THE FRONT HAS NOT QUITE FORMED
YET BUT MODELS INDICATE THAT FRONTOGENESIS WILL OCCUR TONIGHT AS THE
TROUGH APPROACHES. GFS/NAM/ECMWF AGREE ON BRINGING THE FRONT DOWN TO
TOFINO (CYAZ) AT 18Z/11 AM AND THEN JUST E OF PUGET SOUND AT 00Z/5
PM. THE FRONT WILL BE NARROW AND THE SYSTEM FAST MOVING SO THIS
SHOULD BE A QUICK SHOT OF RAIN...STARTING ON THE N COAST JUST AHEAD
OF THE FRONT AROUND 18Z. MODELS SHOW A CONVERGENCE ZONE PATTERN
SETTING UP OVER PUGET SOUND BEHIND THE FRONT TUESDAY EVENING. MODELS
ALSO SHOW A SHOT OF RAIN OVER THE N HALF OF THE INTERIOR AND THE N
CASCADES TUESDAY EVENING AS THE UPPER LEVEL TROUGH AXIS MOVES
THROUGH.

MODELS ARE ALL OVER THE PLACE WITH PRECIP AMOUNTS. THE 18Z NAM
SHOWED VERY LITTLE OVER THE LOWLANDS OUTSIDE OF 0.2 TO 0.3 IN THE
CONVERGENCE ZONE. THE 00Z NAM DISCARDS THE CONVERGENCE ZONE AND ONLY
HAS A FEW HUNDREDTHS OVER THE LOWLANDS. THE 18Z GFS IS SIMILAR TO
THE 18Z NAM. THE 12Z ECMWF HAS 0.5 TO AN INCH OVER THE N HALF OF W
WA. ALL THE MODELS HIT THE N CASCADES WITH 0.5 TO AN INCH. THE
CURRENT FORECAST IS MORE REASONABLE WITH ABOUT A TENTH OF AN INCH
FROM PUGET SOUND NORTHWARD. QPF OVER THE CASCADES COULD PROBABLY BE
DOUBLED TO AT LEAST A HALF INCH...ASSUMING A DECENT HIT FROM THE
UPPER TROUGH AXIS TUESDAY NIGHT.

COLD AIR ALOFT TRAILING THE UPPER LEVEL TROUGH WILL LOWER SNOW
LEVELS DOWN TO A LITTLE ABOVE 6000 FEET LATE TUESDAY NIGHT OVER THE
NORTH AND CENTRAL CASCADES. BUT PRECIP WILL BE MOSTLY OVER BY THEN
SO AT BEST THERE MAY BE UP TO AN INCH OF SNOW OVER THE N CASCADES.

PRECIP WILL BE OVER FOR THE LOWLANDS BY LATE TUESDAY NIGHT...BUT
INCREASING SW ONSHORE FLOW AHEAD OF THE FRONT WILL ENSURE THAT THE
LOWER AIR MASS REMAINS MOIST THROUGH WEDNESDAY MORNING. RAPID DRYING
ALOFT BEHIND THE TROUGH WILL HELP SKIES CLEAR OUT FOR SUNNY
CONDITIONS WEDNESDAY AFTERNOON. THE AIR MASS WILL REMAIN COOL SO
HIGHS WILL ONLY WARM UP A LITTLE TO AROUND 70.

AN UPPER LEVEL RIDGE OFFSHORE WILL BUILD E OVER THE REGION ON
THURSDAY. ONSHORE FLOW WEDNESDAY NIGHT WILL BE NEGLIGIBLE OR EVEN
WEAKLY OFFSHORE...SO WITH A WARMING AIR MASS THURSDAY AND LITTLE OR
NO MORNING STRATUS TO GET IN THE WAY...MAX TEMPS WILL WARM INTO THE
LOWER 70S N TO UPPER 70S SW INTERIOR. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 3 PM AFD...FRIDAY AND
SATURDAY LOOK LIKE THE WARMEST DAYS OF THE WEEK WITH HIGH PRESSURE
ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO WEAKEN ON SATURDAY BUT
THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON TEMPERATURES OR CLOUD
COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LOW LEVEL ONSHORE FLOW CONTINUES ACROSS WESTERN WA
TONIGHT. LOW CLOUDS WILL FILL IN BY MORNING WITH MVFR CONDITIONS
EXPECTED. A COLD FRONT WILL BRING RAIN TO THE COAST AND NORTH
INTERIOR TUE MORNING...WITH SHOWERS SPREADING INTO THE INTERIOR
DURING THE AFTERNOON. THE TRAILING UPPER LEVEL TROUGH WILL BRING
MORE SHOWERS TO THE INTERIOR AND CASCADES TUE NIGHT. 33

KSEA...LOW CLOUDS DEVELOPING OVERNIGHT WITH MVFR CONDITIONS
EXPECTED. SURFACE WINDS ARE LIGHT NORTHERLY...BUT WILL FLIP BACK TO
SOUTHERLY BY 18Z TUE. EXPECT SHOWERS IN THE VICINITY TUE AFTERNOON
AND EVENING. 33

&&

.MARINE...ONSHORE FLOW WILL CONTINUE ACROSS WESTERN WA TONIGHT - A
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE CENTRAL/EAST STRAIT
OF JUAN DE FUCA. ONSHORE FLOW WILL INCREASE BEHIND A COLD FRONT TUE
AFTERNOON WITH GALE FORCE WINDS POSSIBLE OVER THE COASTAL WATERS AND
THROUGH THE STRAIT. ONSHORE FLOW WILL EASE LATE TUE NIGHT. HIGH PRES
OVER THE NE PAC WILL MAINTAIN ONSHORE FLOW THROUGH WED. NORTHERLY
FLOW WILL PREVAIL THU AND FRI AS LOW PRES FORMS ALONG THE COAST. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML














000
FXUS66 KSEW 020350
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
850 PM PDT MON SEP 1 2014

.SYNOPSIS...A VIGOROUS FAST MOVING FRONTAL SYSTEM WILL BRING A
LITTLE RAIN TO WESTERN WASHINGTON ON TUESDAY. A CONVERGENCE ZONE
WILL FORM OVER PUGET SOUND BEHIND THE FRONT LATE TUESDAY AFTERNOON
AND EVENING. DRY NORTH FLOW ALOFT WILL BRING SUNNY WEATHER BY
WEDNESDAY AFTERNOON. AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION
THURSDAY FOR SUNSHINE AND A WARMING TREND THAT WILL LAST INTO NEXT
WEEKEND.

&&

.SHORT TERM...PARTLY TO MOSTLY CLOUDY SKIES OVER W WA THIS EVENING.
WITH NO PRECIP ON RADAR THE DRY FORECAST FOR TONIGHT LOOKS GOOD.

WATER VAPOR IMAGERY SHOWED A VIGOROUS UPPER LEVEL TROUGH OVER THE AK
PANHANDLE AT 03Z. MODELS REMAIN IN GOOD AGREEMENT IN BRINGING THE
TROUGH SE ALONG THE B.C. COAST TONIGHT...THEN DOWN OVER W WA TUE
AFTERNOON. SATELLITE IMAGERY SHOWS THE FRONT HAS NOT QUITE FORMED
YET BUT MODELS INDICATE THAT FRONTOGENESIS WILL OCCUR TONIGHT AS THE
TROUGH APPROACHES. GFS/NAM/ECMWF AGREE ON BRINGING THE FRONT DOWN TO
TOFINO (CYAZ) AT 18Z/11 AM AND THEN JUST E OF PUGET SOUND AT 00Z/5
PM. THE FRONT WILL BE NARROW AND THE SYSTEM FAST MOVING SO THIS
SHOULD BE A QUICK SHOT OF RAIN...STARTING ON THE N COAST JUST AHEAD
OF THE FRONT AROUND 18Z. MODELS SHOW A CONVERGENCE ZONE PATTERN
SETTING UP OVER PUGET SOUND BEHIND THE FRONT TUESDAY EVENING. MODELS
ALSO SHOW A SHOT OF RAIN OVER THE N HALF OF THE INTERIOR AND THE N
CASCADES TUESDAY EVENING AS THE UPPER LEVEL TROUGH AXIS MOVES
THROUGH.

MODELS ARE ALL OVER THE PLACE WITH PRECIP AMOUNTS. THE 18Z NAM
SHOWED VERY LITTLE OVER THE LOWLANDS OUTSIDE OF 0.2 TO 0.3 IN THE
CONVERGENCE ZONE. THE 00Z NAM DISCARDS THE CONVERGENCE ZONE AND ONLY
HAS A FEW HUNDREDTHS OVER THE LOWLANDS. THE 18Z GFS IS SIMILAR TO
THE 18Z NAM. THE 12Z ECMWF HAS 0.5 TO AN INCH OVER THE N HALF OF W
WA. ALL THE MODELS HIT THE N CASCADES WITH 0.5 TO AN INCH. THE
CURRENT FORECAST IS MORE REASONABLE WITH ABOUT A TENTH OF AN INCH
FROM PUGET SOUND NORTHWARD. QPF OVER THE CASCADES COULD PROBABLY BE
DOUBLED TO AT LEAST A HALF INCH...ASSUMING A DECENT HIT FROM THE
UPPER TROUGH AXIS TUESDAY NIGHT.

COLD AIR ALOFT TRAILING THE UPPER LEVEL TROUGH WILL LOWER SNOW
LEVELS DOWN TO A LITTLE ABOVE 6000 FEET LATE TUESDAY NIGHT OVER THE
NORTH AND CENTRAL CASCADES. BUT PRECIP WILL BE MOSTLY OVER BY THEN
SO AT BEST THERE MAY BE UP TO AN INCH OF SNOW OVER THE N CASCADES.

PRECIP WILL BE OVER FOR THE LOWLANDS BY LATE TUESDAY NIGHT...BUT
INCREASING SW ONSHORE FLOW AHEAD OF THE FRONT WILL ENSURE THAT THE
LOWER AIR MASS REMAINS MOIST THROUGH WEDNESDAY MORNING. RAPID DRYING
ALOFT BEHIND THE TROUGH WILL HELP SKIES CLEAR OUT FOR SUNNY
CONDITIONS WEDNESDAY AFTERNOON. THE AIR MASS WILL REMAIN COOL SO
HIGHS WILL ONLY WARM UP A LITTLE TO AROUND 70.

AN UPPER LEVEL RIDGE OFFSHORE WILL BUILD E OVER THE REGION ON
THURSDAY. ONSHORE FLOW WEDNESDAY NIGHT WILL BE NEGLIGIBLE OR EVEN
WEAKLY OFFSHORE...SO WITH A WARMING AIR MASS THURSDAY AND LITTLE OR
NO MORNING STRATUS TO GET IN THE WAY...MAX TEMPS WILL WARM INTO THE
LOWER 70S N TO UPPER 70S SW INTERIOR. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 3 PM AFD...FRIDAY AND
SATURDAY LOOK LIKE THE WARMEST DAYS OF THE WEEK WITH HIGH PRESSURE
ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO WEAKEN ON SATURDAY BUT
THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON TEMPERATURES OR CLOUD
COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LOW LEVEL ONSHORE FLOW CONTINUES ACROSS WESTERN WA
TONIGHT. LOW CLOUDS WILL FILL IN BY MORNING WITH MVFR CONDITIONS
EXPECTED. A COLD FRONT WILL BRING RAIN TO THE COAST AND NORTH
INTERIOR TUE MORNING...WITH SHOWERS SPREADING INTO THE INTERIOR
DURING THE AFTERNOON. THE TRAILING UPPER LEVEL TROUGH WILL BRING
MORE SHOWERS TO THE INTERIOR AND CASCADES TUE NIGHT. 33

KSEA...LOW CLOUDS DEVELOPING OVERNIGHT WITH MVFR CONDITIONS
EXPECTED. SURFACE WINDS ARE LIGHT NORTHERLY...BUT WILL FLIP BACK TO
SOUTHERLY BY 18Z TUE. EXPECT SHOWERS IN THE VICINITY TUE AFTERNOON
AND EVENING. 33

&&

.MARINE...ONSHORE FLOW WILL CONTINUE ACROSS WESTERN WA TONIGHT - A
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE CENTRAL/EAST STRAIT
OF JUAN DE FUCA. ONSHORE FLOW WILL INCREASE BEHIND A COLD FRONT TUE
AFTERNOON WITH GALE FORCE WINDS POSSIBLE OVER THE COASTAL WATERS AND
THROUGH THE STRAIT. ONSHORE FLOW WILL EASE LATE TUE NIGHT. HIGH PRES
OVER THE NE PAC WILL MAINTAIN ONSHORE FLOW THROUGH WED. NORTHERLY
FLOW WILL PREVAIL THU AND FRI AS LOW PRES FORMS ALONG THE COAST. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML















000
FXUS66 KSEW 012229
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT MON SEP 1 2014

.SYNOPSIS...A FRONT WILL BRING A LITTLE RAIN ON TUESDAY. HIGH
PRESSURE ALOFT WILL REBUILD OVER THE AREA FOR THE REST OF THE WEEK
FOR DRY AND WARMER WEATHER. COOLER AND CLOUDIER WEATHER WILL RETURN
EARLY NEXT WEEK AS ONSHORE FLOW INCREASES.

&&

.SHORT TERM...A FAIRLY VIGOROUS UPPER TROUGH AND ASSOCIATED COLD
FRONT WILL MOVE THROUGH THE AREA LATER TUESDAY. THIS SYSTEM WILL
BRING A LITTLE RAIN TO ALL AREAS WITH A PUGET SOUND CONVERGENCE ZONE
LINGERING INTO TUESDAY NIGHT. THE HIGHEST MOUNTAINS ELEVATIONS COULD
SEE A LITTLE SNOW TUESDAY NIGHT AS SNOW LEVELS DROP 7000-7500 FEET.

DRIER NORTHERLY FLOW ALOFT WILL DEVELOP TUESDAY NIGHT AND WEDNESDAY
AS HIGH PRESSURE ALOFT BUILDS OFFSHORE. A FEW SHOWERS WILL LINGER
INTO WEDNESDAY MORNING...MAINLY OVER THE CASCADES. OTHERWISE...DRY
WEATHER WILL RETURN WITH DECREASING CLOUDS ON WEDNESDAY. THURSDAY
SHOULD BE SUNNY AND A WARMER WITH HIGH PRESSURE ALOFT AND NORTHERLY
LOW LEVEL OFFSHORE FLOW DEVELOPING. SCHNEIDER

.LONG TERM...FRIDAY AND SATURDAY LOOK LIKE THE WARMEST DAYS OF THE
WEEK WITH HIGH PRESSURE ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO
WEAKEN ON SATURDAY BUT THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON
TEMPERATURES OR CLOUD COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LIGHT NW FLOW ALOFT WILL BECOME WESTERLY OVERNIGHT AND
STRENGTHEN TUESDAY AS VIGOROUS SYSTEM APPROACHES WASHINGTON FROM THE
NORTH. THE RELATIVELY MOIST AIR MASS HAS BECOME WEAKLY UNSTABLE THIS
AFTERNOON...AND THERE REMAINS A SLIGHT CHANCE OF SHOWERS...MAINLY
OVER THE NORTH COAST AND NORTH THIS AFTERNOON AS A VERY WEAK FRONT
MOVES ONSHORE AND FALLS APART. RADAR IMAGERY AND SURFACE
OBSERVATIONS CONFIRM THIS...SHOWING A FEW LIGHT SHOWERS MOVING
INLAND AS OF 21Z/2PM.  CEILINGS OVER MUCH OF THE INTERIOR HAVE
SCATTERED OUT OVER THE LAST COUPLE OF HOURS AND VFR CONDITIONS
PREVAIL. THE EXCEPTION IS THE STRAIT...SOUTHWEST INTERIOR...AND
CENTRAL WASHINGTON COAST WHERE A BKN BUT VFR DECK IS HANGING ON. THE
NORTH COAST HAS SEEN CEILINGS LOWER TO MVFR AND IFR LEVELS WITH THE
SHOWERS THAT HAVE MOVED ON SHORE THERE. EXPECT CONDITIONS ALL AREAS
TO IMPROVE OR REMAIN VFR THIS EVENING. THE COAST AND STRAIT AS WELL
AS THE SOUTHWEST INTERIOR MAY HAVE A TOUGH TIME SCATTERING
COMPLETELY OUT THIS EVENING. EXPECT CEILINGS TO FILL AND LOWER
THROUGH EARLY TUESDAY MORNING WITH MOST LOCATIONS BECOMING MVFR BY
DAYBREAK...WHILE THE COAST WILL LIKELY DROP TO IFR LEVELS.
INCREASING MID AND HIGH CLOUDS AS WELL AS SHOWERS TUESDAY WITH THE
APPROACHING UPPER LEVEL TROUGH.

KSEA...SW WIND 4-7 KT WILL BECOME N AFTER 00Z/5 PM...THEN NE AND
LIGHT AFTER 8Z/1AM. VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING...THEN FILL AND LOWER EARLY TUESDAY MORNING TO MVFR LEVELS.
INCREASING SHOWERS TUESDAY.

&&

.MARINE...SOLID ONSHORE FLOW WILL DEVELOP AS GRADIENTS THROUGH THE
STRAIT TIGHTEN OVERNIGHT...BRINGING SMALL CRAFT WINDS TO THE CENTRAL
AND EAST STRAIT THROUGH EARLY TUESDAY MORNING. A MORE VIGOROUS
SYSTEM MOVING INTO THE AREA WATERS TUESDAY WILL BRING ANOTHER BOUT
OF WINDS TO AREA WATERS. EXPECT STRONG SOUTHWESTERLIES OVER THE
COASTAL WATERS FOLLOWED BY NORTHWESTERLIES BEHIND THE FRONT. ONSHORE
GRADIENTS REMAIN FORECAST TO BE STRONG TOMORROW EVENING. WINDS OVER
THE COASTAL WATERS AND MUCH OF THE STRAIT WILL LIKELY BE HIGH END
SMALL CRAFT...POSSIBLY REACHING GALE CRITERIA. HAVE ISSUED A GALE
WATCH FOR THE COASTAL WATERS AND CENTRAL AND EAST STRAIT TUESDAY
AFTERNOON THROUGH LATE TUESDAY NIGHT. GRADIENTS EASE ON WEDNESDAY
THEN RETURN TO A TYPICAL LATE SUMMER PATTERN THROUGH THE REST OF THE
WEEK.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 012229
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT MON SEP 1 2014

.SYNOPSIS...A FRONT WILL BRING A LITTLE RAIN ON TUESDAY. HIGH
PRESSURE ALOFT WILL REBUILD OVER THE AREA FOR THE REST OF THE WEEK
FOR DRY AND WARMER WEATHER. COOLER AND CLOUDIER WEATHER WILL RETURN
EARLY NEXT WEEK AS ONSHORE FLOW INCREASES.

&&

.SHORT TERM...A FAIRLY VIGOROUS UPPER TROUGH AND ASSOCIATED COLD
FRONT WILL MOVE THROUGH THE AREA LATER TUESDAY. THIS SYSTEM WILL
BRING A LITTLE RAIN TO ALL AREAS WITH A PUGET SOUND CONVERGENCE ZONE
LINGERING INTO TUESDAY NIGHT. THE HIGHEST MOUNTAINS ELEVATIONS COULD
SEE A LITTLE SNOW TUESDAY NIGHT AS SNOW LEVELS DROP 7000-7500 FEET.

DRIER NORTHERLY FLOW ALOFT WILL DEVELOP TUESDAY NIGHT AND WEDNESDAY
AS HIGH PRESSURE ALOFT BUILDS OFFSHORE. A FEW SHOWERS WILL LINGER
INTO WEDNESDAY MORNING...MAINLY OVER THE CASCADES. OTHERWISE...DRY
WEATHER WILL RETURN WITH DECREASING CLOUDS ON WEDNESDAY. THURSDAY
SHOULD BE SUNNY AND A WARMER WITH HIGH PRESSURE ALOFT AND NORTHERLY
LOW LEVEL OFFSHORE FLOW DEVELOPING. SCHNEIDER

.LONG TERM...FRIDAY AND SATURDAY LOOK LIKE THE WARMEST DAYS OF THE
WEEK WITH HIGH PRESSURE ALOFT IN CONTROL. THE RIDGE WILL BEGIN TO
WEAKEN ON SATURDAY BUT THAT IS NOT EXPECTED TO HAVE MUCH IMPACT ON
TEMPERATURES OR CLOUD COVER.

IT LOOKS LIKE THERE WILL A MARINE PUSH SATURDAY NIGHT WITH AN UPPER
TROUGH MOVING OVER THE AREA ON SUNDAY AND MONDAY FOR COOLER AND
CLOUDIER WEATHER WITH A CHANCE OF SHOWERS AT TIMES. THE MODELS ARE
NOT IN GOOD AGREEMENT WITH THESE DETAILS HOWEVER. SCHNEIDER

&&

.AVIATION...LIGHT NW FLOW ALOFT WILL BECOME WESTERLY OVERNIGHT AND
STRENGTHEN TUESDAY AS VIGOROUS SYSTEM APPROACHES WASHINGTON FROM THE
NORTH. THE RELATIVELY MOIST AIR MASS HAS BECOME WEAKLY UNSTABLE THIS
AFTERNOON...AND THERE REMAINS A SLIGHT CHANCE OF SHOWERS...MAINLY
OVER THE NORTH COAST AND NORTH THIS AFTERNOON AS A VERY WEAK FRONT
MOVES ONSHORE AND FALLS APART. RADAR IMAGERY AND SURFACE
OBSERVATIONS CONFIRM THIS...SHOWING A FEW LIGHT SHOWERS MOVING
INLAND AS OF 21Z/2PM.  CEILINGS OVER MUCH OF THE INTERIOR HAVE
SCATTERED OUT OVER THE LAST COUPLE OF HOURS AND VFR CONDITIONS
PREVAIL. THE EXCEPTION IS THE STRAIT...SOUTHWEST INTERIOR...AND
CENTRAL WASHINGTON COAST WHERE A BKN BUT VFR DECK IS HANGING ON. THE
NORTH COAST HAS SEEN CEILINGS LOWER TO MVFR AND IFR LEVELS WITH THE
SHOWERS THAT HAVE MOVED ON SHORE THERE. EXPECT CONDITIONS ALL AREAS
TO IMPROVE OR REMAIN VFR THIS EVENING. THE COAST AND STRAIT AS WELL
AS THE SOUTHWEST INTERIOR MAY HAVE A TOUGH TIME SCATTERING
COMPLETELY OUT THIS EVENING. EXPECT CEILINGS TO FILL AND LOWER
THROUGH EARLY TUESDAY MORNING WITH MOST LOCATIONS BECOMING MVFR BY
DAYBREAK...WHILE THE COAST WILL LIKELY DROP TO IFR LEVELS.
INCREASING MID AND HIGH CLOUDS AS WELL AS SHOWERS TUESDAY WITH THE
APPROACHING UPPER LEVEL TROUGH.

KSEA...SW WIND 4-7 KT WILL BECOME N AFTER 00Z/5 PM...THEN NE AND
LIGHT AFTER 8Z/1AM. VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING...THEN FILL AND LOWER EARLY TUESDAY MORNING TO MVFR LEVELS.
INCREASING SHOWERS TUESDAY.

&&

.MARINE...SOLID ONSHORE FLOW WILL DEVELOP AS GRADIENTS THROUGH THE
STRAIT TIGHTEN OVERNIGHT...BRINGING SMALL CRAFT WINDS TO THE CENTRAL
AND EAST STRAIT THROUGH EARLY TUESDAY MORNING. A MORE VIGOROUS
SYSTEM MOVING INTO THE AREA WATERS TUESDAY WILL BRING ANOTHER BOUT
OF WINDS TO AREA WATERS. EXPECT STRONG SOUTHWESTERLIES OVER THE
COASTAL WATERS FOLLOWED BY NORTHWESTERLIES BEHIND THE FRONT. ONSHORE
GRADIENTS REMAIN FORECAST TO BE STRONG TOMORROW EVENING. WINDS OVER
THE COASTAL WATERS AND MUCH OF THE STRAIT WILL LIKELY BE HIGH END
SMALL CRAFT...POSSIBLY REACHING GALE CRITERIA. HAVE ISSUED A GALE
WATCH FOR THE COASTAL WATERS AND CENTRAL AND EAST STRAIT TUESDAY
AFTERNOON THROUGH LATE TUESDAY NIGHT. GRADIENTS EASE ON WEDNESDAY
THEN RETURN TO A TYPICAL LATE SUMMER PATTERN THROUGH THE REST OF THE
WEEK.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH COASTAL WATERS...CENTRAL AND EASTERN STRAIT OF JUAN
     DE FUCA TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML












000
FXUS66 KSEW 011610
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PDT MON SEP 1 2014

.SYNOPSIS...WEAK HIGH PRESSURE ALOFT WILL PREVAIL OVER THE AREA
TODAY FOR A DRY DAY. A FRONT WILL BRING A LITTLE RAIN ON TUESDAY.
HIGH PRESSURE ALOFT WILL REBUILD OVER THE AREA FOR THE REST OF THE
WEEK FOR DRY AND WARMER WEATHER.

&&

.SHORT TERM...NORTHWEST FLOW ALOFT WILL PREVAIL TODAY FOR A
GENERALLY DRY DAY. A WEAK DECAYING FRONT COULD BRING A FEW SPRINKLES
TO THE COAST BUT THAT SHOULD BE ABOUT IT. CLOUDS ARE CURRENTLY A
LITTLE MORE EXTENSIVE THAT PREVIOUSLY EXPECTED BUT THE TREND TOWARDS
A PARTLY SUNNY DAY FOR THE INTERIOR STILL LOOKS GOOD.

A FAIRLY VIGOROUS UPPER TROUGH AND ASSOCIATED COLD FRONT WILL MOVE
THROUGH THE AREA LATER TUESDAY. THIS SYSTEM LOOKS LIKE IT WILL BRING
A LITTLE RAIN TO ALL AREAS WITH A PUGET SOUND CONVERGENCE ZONE
LINGERING INTO TUESDAY NIGHT. THE HIGHEST PARTS OF THE MOUNTAINS
COULD SEE A LITTLE SNOW TUESDAY NIGHT AS SNOW LEVELS DROP TO AROUND
6500 FEET...THE FIRST SIGN THAT FALL IS NOT FAR AWAY.

DRIER NORTHERLY FLOW ALOFT WILL QUICKLY DEVELOP TUESDAY NIGHT AND
WEDNESDAY AS HIGH PRESSURE ALOFT BUILDS OFFSHORE. THIS WILL BRING A
RETURN TO DRY WEATHER WITH DECREASING CLOUDS. SCHNEIDER

.LONG TERM...AN UPPER RIDGE OVER THE NORTHEAST PACIFIC WILL KEEP THE
WEATHER DRY FOR THE REMAINDER OF THE WEEK WITH PLENTY OF SUNSHINE.
THERE WILL EVEN BE A BIT OF A THERMAL TROUGH ALONG THE COAST FOR
OFFSHORE FLOW. THIS SHOULD ALLOW HIGHS TO WARM TO NEAR 80 BY FRIDAY
OR SATURDAY. THE UPPER RIDGE LOOKS LIKE IT WILL BREAK DOWN AROUND
SUNDAY WITH A RETURN TO ONSHORE FLOW...INCREASED CLOUDINESS...AND
HIGHS COOLING BACK TO NEAR NORMAL. SCHNEIDER

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION WILL BECOME WESTERLY
AND STRENGTHEN TUESDAY AS AN UPPER LEVEL TROUGH APPROACHES
WASHINGTON FROM THE NORTH. THE MOIST AND STABLE AIR MASS THIS
MORNING WILL BECOME WEAKLY UNSTABLE THIS AFTERNOON WITH A SLIGHT
CHANCE OF SHOWERS...MAINLY N OF SEATTLE THIS AFTERNOON. CEILINGS
OVER THE CENTRAL SOUND HAVE FILLED IN AND LOWERED SOMEWHAT OVER THE
LAST HOUR OR SO TO MVFR LEVELS WITH A FEW SPOTS A BIT LOWER. EXPECT
GENERAL CONDITIONS TO IMPROVE WITH CEILINGS LIFTING TO VFR LEVELS
AROUND 18Z. INCREASING MID AND HIGH CLOUDS WILL LIKELY KEEP SKIES
FROM COMPLETELY SCATTERING OUT...BUT EXPECT VFR CONDITIONS TO
PERSIST THROUGH THE EVENING HOURS. INCREASING SHOWERS TUESDAY WITH
THE APPROACHING UPPER LEVEL TROUGH.

KSEA...S WIND TO 4-7 KT AFTER 19Z/12 PM THEN SWITCHING TO THE N
AFTER 00Z/5 PM THIS AFTERNOON. IFR CIGS THIS MORNING WILL BECOME
MVFR OVER THE NEXT HOUR THEN VFR BY 18Z/11 AM. VFR CONDITIONS WILL
PREVAIL THROUGH THIS EVENING WITH A BKN-OVC 4-5K FT DECK...THEN FILL
AND LOWER EARLY TUESDAY MORNING TO MVFR LEVELS. THERE REMAINS A
SLIGHT CHANCE OF A SHOWER THROUGH TONIGHT. INCREASING SHOWERS
TUESDAY.

&&

.MARINE...A SURFACE TROUGH WILL DISSIPATE OVER THE COASTAL WATERS
TODAY. SLY WINDS AHEAD OF THE TROUGH SHOULD REMAIN BELOW 20 KT OVER
THE COASTAL WATERS...WITH LIGHT SLY WIND OVER THE INLAND WATERS.
SOLID ONSHORE FLOW THROUGH THE STRAIT WILL DEVELOP TONIGHT AS
GRADIENTS TIGHTEN OVERNIGHT FOLLOWED BY ANOTHER SYSTEM THAT WILL
BRING ANOTHER BOUT OF STRONG ONSHORE FLOW TUESDAY NIGHT. GRADIENTS
EASE ON WEDNESDAY THEN RETURN TO A TYPICAL LATE SUMMER PATTERN
THROUGH THE REST OF THE WEEK.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA TUESDAY
     AFTERNOON THROUGH LATE TUESDAY NIGHT.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML








000
FXUS66 KSEW 011610
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PDT MON SEP 1 2014

.SYNOPSIS...WEAK HIGH PRESSURE ALOFT WILL PREVAIL OVER THE AREA
TODAY FOR A DRY DAY. A FRONT WILL BRING A LITTLE RAIN ON TUESDAY.
HIGH PRESSURE ALOFT WILL REBUILD OVER THE AREA FOR THE REST OF THE
WEEK FOR DRY AND WARMER WEATHER.

&&

.SHORT TERM...NORTHWEST FLOW ALOFT WILL PREVAIL TODAY FOR A
GENERALLY DRY DAY. A WEAK DECAYING FRONT COULD BRING A FEW SPRINKLES
TO THE COAST BUT THAT SHOULD BE ABOUT IT. CLOUDS ARE CURRENTLY A
LITTLE MORE EXTENSIVE THAT PREVIOUSLY EXPECTED BUT THE TREND TOWARDS
A PARTLY SUNNY DAY FOR THE INTERIOR STILL LOOKS GOOD.

A FAIRLY VIGOROUS UPPER TROUGH AND ASSOCIATED COLD FRONT WILL MOVE
THROUGH THE AREA LATER TUESDAY. THIS SYSTEM LOOKS LIKE IT WILL BRING
A LITTLE RAIN TO ALL AREAS WITH A PUGET SOUND CONVERGENCE ZONE
LINGERING INTO TUESDAY NIGHT. THE HIGHEST PARTS OF THE MOUNTAINS
COULD SEE A LITTLE SNOW TUESDAY NIGHT AS SNOW LEVELS DROP TO AROUND
6500 FEET...THE FIRST SIGN THAT FALL IS NOT FAR AWAY.

DRIER NORTHERLY FLOW ALOFT WILL QUICKLY DEVELOP TUESDAY NIGHT AND
WEDNESDAY AS HIGH PRESSURE ALOFT BUILDS OFFSHORE. THIS WILL BRING A
RETURN TO DRY WEATHER WITH DECREASING CLOUDS. SCHNEIDER

.LONG TERM...AN UPPER RIDGE OVER THE NORTHEAST PACIFIC WILL KEEP THE
WEATHER DRY FOR THE REMAINDER OF THE WEEK WITH PLENTY OF SUNSHINE.
THERE WILL EVEN BE A BIT OF A THERMAL TROUGH ALONG THE COAST FOR
OFFSHORE FLOW. THIS SHOULD ALLOW HIGHS TO WARM TO NEAR 80 BY FRIDAY
OR SATURDAY. THE UPPER RIDGE LOOKS LIKE IT WILL BREAK DOWN AROUND
SUNDAY WITH A RETURN TO ONSHORE FLOW...INCREASED CLOUDINESS...AND
HIGHS COOLING BACK TO NEAR NORMAL. SCHNEIDER

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION WILL BECOME WESTERLY
AND STRENGTHEN TUESDAY AS AN UPPER LEVEL TROUGH APPROACHES
WASHINGTON FROM THE NORTH. THE MOIST AND STABLE AIR MASS THIS
MORNING WILL BECOME WEAKLY UNSTABLE THIS AFTERNOON WITH A SLIGHT
CHANCE OF SHOWERS...MAINLY N OF SEATTLE THIS AFTERNOON. CEILINGS
OVER THE CENTRAL SOUND HAVE FILLED IN AND LOWERED SOMEWHAT OVER THE
LAST HOUR OR SO TO MVFR LEVELS WITH A FEW SPOTS A BIT LOWER. EXPECT
GENERAL CONDITIONS TO IMPROVE WITH CEILINGS LIFTING TO VFR LEVELS
AROUND 18Z. INCREASING MID AND HIGH CLOUDS WILL LIKELY KEEP SKIES
FROM COMPLETELY SCATTERING OUT...BUT EXPECT VFR CONDITIONS TO
PERSIST THROUGH THE EVENING HOURS. INCREASING SHOWERS TUESDAY WITH
THE APPROACHING UPPER LEVEL TROUGH.

KSEA...S WIND TO 4-7 KT AFTER 19Z/12 PM THEN SWITCHING TO THE N
AFTER 00Z/5 PM THIS AFTERNOON. IFR CIGS THIS MORNING WILL BECOME
MVFR OVER THE NEXT HOUR THEN VFR BY 18Z/11 AM. VFR CONDITIONS WILL
PREVAIL THROUGH THIS EVENING WITH A BKN-OVC 4-5K FT DECK...THEN FILL
AND LOWER EARLY TUESDAY MORNING TO MVFR LEVELS. THERE REMAINS A
SLIGHT CHANCE OF A SHOWER THROUGH TONIGHT. INCREASING SHOWERS
TUESDAY.

&&

.MARINE...A SURFACE TROUGH WILL DISSIPATE OVER THE COASTAL WATERS
TODAY. SLY WINDS AHEAD OF THE TROUGH SHOULD REMAIN BELOW 20 KT OVER
THE COASTAL WATERS...WITH LIGHT SLY WIND OVER THE INLAND WATERS.
SOLID ONSHORE FLOW THROUGH THE STRAIT WILL DEVELOP TONIGHT AS
GRADIENTS TIGHTEN OVERNIGHT FOLLOWED BY ANOTHER SYSTEM THAT WILL
BRING ANOTHER BOUT OF STRONG ONSHORE FLOW TUESDAY NIGHT. GRADIENTS
EASE ON WEDNESDAY THEN RETURN TO A TYPICAL LATE SUMMER PATTERN
THROUGH THE REST OF THE WEEK.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
    .GALE WATCH CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA TUESDAY
     AFTERNOON THROUGH LATE TUESDAY NIGHT.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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000
FXUS66 KSEW 011011
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
311 AM PDT MON SEP 1 2014

.SYNOPSIS...HIGH PRESSURE ALOFT WILL PREVAIL OVER THE AREA TODAY.
A STRONG AND FAST MOVING LOW PRESSURE SYSTEM WILL IMPACT THE
REGION ON TUESDAY. LOOK FOR HIGH PRESSURE ALOFT TO PREVAIL OVER
THE AREA THE REST OF THE WEEK FOR DRY AND WARMER CONDITIONS.

&&

.SHORT TERM...
AN UPPER RIDGE WILL PREVAIL OVER THE REGION TODAY AND WILL WEAKEN
TONIGHT. EXPECT DAYTIME HIGHS TO BE NEAR NORMAL FOR THIS TIME OF
THE YEAR.

A VIGOROUS LOW PRESSURE SYSTEM EMANATING FROM THE GULF OF AK WILL
IMPACT THE PACIFIC NORTHWEST ON TUE. THE BEST CHANCE OF PRECIP
WILL BE ACROSS THE NORTHERN PART OF THE CWA AND WITHIN THE PUGET
SOUND CONVERGENCE ZONE /PSCZ/. THE PSCZ SHOULD DEVELOP QUICKLY
BEHIND THE COLD FRONT LATE TUE AFTERNOON OR EARLY EVENING. WOULD
NOT BE SURPRISED IF THERE WERE ISOLATED TSTMS WITH SMALL HAIL
ASSOCIATED WITH THE PSCZ. WINDS WILL ALSO KICK UP AHEAD OF THE
COLD FRONT. HAVE A FEELING THAT THE MODELS MIGHT BE UNDER-
PREDICTING WIND SPEEDS IN SOME PLACES.

THE SNOW LEVEL WILL PLUMMET TO NEAR 6500 FEET ACROSS MUCH OF THE
CASCADES LATE TUE NIGHT IN THE WAKE OF THE COLD FRONT BUT LITTLE
/IF ANY/ SNOW ACCUMULATION IS EXPECTED SINCE THE AIR MASS WILL BE
UNDERGOING STRONG DRYING AND SUBSIDENCE AT THAT TIME.

STRONG...DRY NORTHERLY FLOW ALOFT WILL PREVAIL OVER THE REGION ON
WED. DAYTIME TEMPS WILL REBOUND SLIGHTLY BUT REMAIN BELOW NORMAL.
WED NIGHT WILL LIKELY BE THE CHILLIEST NIGHT ACROSS THE LOWLANDS
UNDER A CLOUDLESS SKY. MOST PLACES WILL EXPERIENCE MINIMUMS IN THE
40S.

.LONG TERM...
NO CHANGES WERE MADE TO THE INHERITED FORECAST EXCEPT TO BLEND
WITH ADJACENT FORECAST OFFICES. AN UPPER RIDGE WILL DOMINATE THE
WEATHER PATTERN OVER THE PACIFIC NORTHWEST DURING THIS PERIOD.

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION THROUGH TONIGHT.
STRONG WESTERLY FLOW ALOFT DEVELOPS ON TUESDAY AS A TROUGH
APPROACHES WA. THE AIR MASS IS GENERALLY MOIST AND STABLE...EXCEPT
BECOMING WEAKLY UNSTABLE THIS AFTERNOON. ONLY A SLIGHT CHANCE OF A
FEW SHOWERS...MAINLY N OF SEATTLE THIS AFTERNOON. INCREASING SHOWERS
TUESDAY. AN MVFR CEILING OVER PORTIONS OF WRN WA THIS MORNING WILL
LIFT AND SCATTER BY 18Z.

KSEA...S WIND TO 5 KT...BECOMING SLY 4-7 KT AFTER 19Z THEN SWITCHING
TO THE N AFTER 5 PM THIS AFTERNOON. MVFR CIGS THIS MORNING WILL LIFT
AND SCATTER BY 18-19Z. A BKN-OVC 4-5K FT DECK WILL FILL IN THIS
EVENING. SLIGHT CHANCE OF A SHOWER THROUGH TONIGHT. INCREASING
SHOWERS TUESDAY. DTM

&&

.MARINE...A SURFACE TROUGH WILL DISSIPATE OVER THE COASTAL WATERS BY
MIDDAY. SLY WINDS AHEAD OF THE TROUGH SHOULD REMAIN BELOW 20 KT OVER
THE COASTAL WATERS...WITH LIGHT SLY WIND OVER THE INLAND WATERS.
ANOTHER SYSTEM WILL BRING A BOUT OF STRONG ONSHORE FLOW TUESDAY
NIGHT...THEN EASING ON WEDNESDAY. THE REST OF THE WEEK WILL BE A
MORE SUMMERY WIND REGIME WITH A TYPICAL NW BREEZE EACH DAY. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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000
FXUS66 KSEW 011011
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
311 AM PDT MON SEP 1 2014

.SYNOPSIS...HIGH PRESSURE ALOFT WILL PREVAIL OVER THE AREA TODAY.
A STRONG AND FAST MOVING LOW PRESSURE SYSTEM WILL IMPACT THE
REGION ON TUESDAY. LOOK FOR HIGH PRESSURE ALOFT TO PREVAIL OVER
THE AREA THE REST OF THE WEEK FOR DRY AND WARMER CONDITIONS.

&&

.SHORT TERM...
AN UPPER RIDGE WILL PREVAIL OVER THE REGION TODAY AND WILL WEAKEN
TONIGHT. EXPECT DAYTIME HIGHS TO BE NEAR NORMAL FOR THIS TIME OF
THE YEAR.

A VIGOROUS LOW PRESSURE SYSTEM EMANATING FROM THE GULF OF AK WILL
IMPACT THE PACIFIC NORTHWEST ON TUE. THE BEST CHANCE OF PRECIP
WILL BE ACROSS THE NORTHERN PART OF THE CWA AND WITHIN THE PUGET
SOUND CONVERGENCE ZONE /PSCZ/. THE PSCZ SHOULD DEVELOP QUICKLY
BEHIND THE COLD FRONT LATE TUE AFTERNOON OR EARLY EVENING. WOULD
NOT BE SURPRISED IF THERE WERE ISOLATED TSTMS WITH SMALL HAIL
ASSOCIATED WITH THE PSCZ. WINDS WILL ALSO KICK UP AHEAD OF THE
COLD FRONT. HAVE A FEELING THAT THE MODELS MIGHT BE UNDER-
PREDICTING WIND SPEEDS IN SOME PLACES.

THE SNOW LEVEL WILL PLUMMET TO NEAR 6500 FEET ACROSS MUCH OF THE
CASCADES LATE TUE NIGHT IN THE WAKE OF THE COLD FRONT BUT LITTLE
/IF ANY/ SNOW ACCUMULATION IS EXPECTED SINCE THE AIR MASS WILL BE
UNDERGOING STRONG DRYING AND SUBSIDENCE AT THAT TIME.

STRONG...DRY NORTHERLY FLOW ALOFT WILL PREVAIL OVER THE REGION ON
WED. DAYTIME TEMPS WILL REBOUND SLIGHTLY BUT REMAIN BELOW NORMAL.
WED NIGHT WILL LIKELY BE THE CHILLIEST NIGHT ACROSS THE LOWLANDS
UNDER A CLOUDLESS SKY. MOST PLACES WILL EXPERIENCE MINIMUMS IN THE
40S.

.LONG TERM...
NO CHANGES WERE MADE TO THE INHERITED FORECAST EXCEPT TO BLEND
WITH ADJACENT FORECAST OFFICES. AN UPPER RIDGE WILL DOMINATE THE
WEATHER PATTERN OVER THE PACIFIC NORTHWEST DURING THIS PERIOD.

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION THROUGH TONIGHT.
STRONG WESTERLY FLOW ALOFT DEVELOPS ON TUESDAY AS A TROUGH
APPROACHES WA. THE AIR MASS IS GENERALLY MOIST AND STABLE...EXCEPT
BECOMING WEAKLY UNSTABLE THIS AFTERNOON. ONLY A SLIGHT CHANCE OF A
FEW SHOWERS...MAINLY N OF SEATTLE THIS AFTERNOON. INCREASING SHOWERS
TUESDAY. AN MVFR CEILING OVER PORTIONS OF WRN WA THIS MORNING WILL
LIFT AND SCATTER BY 18Z.

KSEA...S WIND TO 5 KT...BECOMING SLY 4-7 KT AFTER 19Z THEN SWITCHING
TO THE N AFTER 5 PM THIS AFTERNOON. MVFR CIGS THIS MORNING WILL LIFT
AND SCATTER BY 18-19Z. A BKN-OVC 4-5K FT DECK WILL FILL IN THIS
EVENING. SLIGHT CHANCE OF A SHOWER THROUGH TONIGHT. INCREASING
SHOWERS TUESDAY. DTM

&&

.MARINE...A SURFACE TROUGH WILL DISSIPATE OVER THE COASTAL WATERS BY
MIDDAY. SLY WINDS AHEAD OF THE TROUGH SHOULD REMAIN BELOW 20 KT OVER
THE COASTAL WATERS...WITH LIGHT SLY WIND OVER THE INLAND WATERS.
ANOTHER SYSTEM WILL BRING A BOUT OF STRONG ONSHORE FLOW TUESDAY
NIGHT...THEN EASING ON WEDNESDAY. THE REST OF THE WEEK WILL BE A
MORE SUMMERY WIND REGIME WITH A TYPICAL NW BREEZE EACH DAY. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 010334
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
834 PM PDT SUN AUG 31 2014

.SYNOPSIS...A WEAK UPPER LEVEL TROUGH CROSSING THE AREA WILL
MAINTAIN A CHANCE OF SHOWERS OVER THE CASCADES TONIGHT. THE
ASSOCIATED WEAK FRONT WILL BRING A CHANCE OF SHOWERS TO THE NORTH
COAST AND NORTH CASCADES LATE TONIGHT AND MONDAY. MOSTLY CLOUDY
SKIES WILL CONTINUE OVER THE REST OF WESTERN WASHINGTON. RAIN IS
LIKELY ON TUESDAY AS A VIGOROUS UPPER LEVEL TROUGH CROSSES THE
REGION. AN UPPER LEVEL RIDGE OFFSHORE WILL BRING A GRADUAL WARMING
AND DRYING PATTERN FROM WEDNESDAY THROUGH NEXT WEEKEND.

&&

.SHORT TERM...WATER VAPOR IMAGERY SHOWS A WEAK UPPER LEVEL SHORTWAVE
TROUGH ALONG THE B.C. COAST THAT WILL BRUSH PAST THE NORTH PART OF W
WA TONIGHT. THE WILL BRING A CHANCE OF SHOWERS TO THE CASCADES...BUT
MAINLY THE NORTH PART. IR AND VISIBLE SATELLITE IMAGERY SHOW A LOT
OF MID LEVEL CLOUDS JUST OFFSHORE THAT SHOULD SPREAD OVER W WA
OVERNIGHT...ALTHOUGH THE OLYMPICS MAY SHIELD THE PUGET SOUND REGION
A BIT. THE VERY WEAK SURFACE FRONT PRESENTLY ASSOCIATED WITH THE
UPPER TROUGH WILL GLIDE TO THE COAST LATE TONIGHT THEN FALL APART
MONDAY. A LITTLE LIGHT RAIN IS POSSIBLE FOR THE N COAST AND N
INTERIOR MONDAY AS THE FRONT DISSIPATES. THE PUGET SOUND REGION AND
SW INTERIOR WILL PROBABLY BE THE LEAST AFFECTED BY THE DISSIPATING
FRONT AND SO COULD SEE SOME PARTIAL SUNSHINE MONDAY AFTERNOON.

MODELS HAVE BEEN REASONABLY CONSISTENT WITH THE TIMING AND TRACK OF
THE VIGOROUS UPPER LEVEL TROUGH THAT IS EXPECTED TO CROSS THE AREA
ON TUESDAY. THIS TROUGH SHOWS UP NICELY ON WATER VAPOR IMAGERY OVER
THE GULF OF AK THIS EVENING...AND WILL MOVE SE ALONG THE B.C. COAST
THROUGH MONDAY NIGHT...ENDING UP OVER W WA ON TUESDAY. LATEST MODEL
TIMING HAS THE BEST CHANCE OF RAIN TUESDAY AFTERNOON. THE NAM IS THE
DRIEST MODEL WITH ONLY A FEW HUNDREDTHS OF AN INCH OF RAIN...WHILE
THE ECMWF IS WETTEST WITH 2 TO 4 TENTHS OVER THE NORTH. THIS IS A
FAIRLY DRY TRACK FOR THE TROUGH AND IT IS FAST MOVING...SO ACTUAL
RAINFALL ACCUMULATIONS WILL PROBABLY FALL IN-BETWEEN THE TWO MODELS.
THE TROUGH WILL DRAG MUCH COOLER AIR ALOFT OVER THE AREA TUESDAY
NIGHT WITH SNOW LEVELS OVER THE CASCADES DROPPING DOWN TO JUST ABOVE
6000 FEET AFTER MIDNIGHT. THERE COULD STILL BE SOME LIGHT SHOWERS
AROUND FOR A TINY BIT OF MOUNTAIN S.N.O.W.

THE UPPER LEVEL TROUGH WILL MOVE QUICKLY EAST TUESDAY
NIGHT...ALLOWING DRIER N FLOW ALOFT FROM AN OFFSHORE UPPER LEVEL
RIDGE TO MOVE OVER THE AREA. WELL DEVELOPED SW ONSHORE FLOW TUESDAY
NIGHT WILL KEEP THE LOWER AIR MASS MOIST WITH STRATUS THROUGH
WEDNESDAY MORNING. WITH DRY AIR ALOFT THE STRATUS SHOULD CLEAR OUT
BY AFTERNOON. WEDNESDAY SHOULD BE SLIGHTLY WARMER THAN TUESDAY...BUT
THE RESIDUAL COOL AIR MASS FROM THE UPPER TROUGH WILL CAP MAX TEMPS
IN THE 60S TO NEAR 70. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 334 PM AFD...MEDIUM RANGE
MODELS ALL AGREE ON THE ZONAL FLOW OVER THE NORTHEAST PACIFIC
BUCKLING INTO A HIGHER AMPLITUDE PATTERN BY MIDWEEK. THIS PATTERN
WILL BE ANCHORED BY A LARGE SCALE RIDGE THAT WILL BUILD ALONG 140W
TUESDAY AND INTO BRITISH COLUMBIA BY WEDNESDAY NIGHT. MODELS DO
DISAGREE ON THE FLOW DOWNSTREAM OF THE RIDGE ON FRIDAY WITH VARYING
DEGREES OF SPLIT FLOW ALOFT OVER THE NORTHWEST AND A WEAK UPPER
LEVEL LOW OVER THE GREAT BASIN OR CENTRAL ROCKY MOUNTAINS.
NONETHELESS THE LARGE SCALE PATTERN WILL KEEP THE PACIFIC NORTHWEST
DRIER AND WARMER BEGINNING WEDNESDAY AFTERNOON AND PERSISTING
THROUGH THE WEEKEND. MODELS GENERALLY AGREE ON A SYSTEM RIDING OVER
THE TOP RIDGE AND INTO THE NORTHWEST LATE SUNDAY INTO MONDAY
MORNING.

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION THROUGH MONDAY.
LIGHT LOW LEVEL ONSHORE FLOW. A WEAK TROUGH WILL DISSIPATE AS IT
REACHES THE COAST MONDAY MORNING. THE AIR MASS IS GENERALLY MOIST
AND STABLE...EXCEPT WEAKLY UNSTABLE MONDAY AFTERNOON. ONLY A SLIGHT
CHANCE OF A FEW SHOWERS...MAINLY N OF SEATTLE ON MONDAY AFTERNOON.
AN MVFR CEILING IS EXPECTED TO FORM OVER SOME PARTS OF THE AREA LATE
TONIGHT AND MONDAY MORNING...LIFTING AND SCATTERING BY 18Z.

KSEA...LIGHT WIND...BECOMING S-SW TO 5 KNOTS LATE TONIGHT AND
MONDAY. MVFR CIGS ARE LIKELY TO FORM AFTER MIDNIGHT...THEN LIFT AND
SCATTER BY 18Z. DTM

&&

.MARINE...A WEAK SYSTEM WILL DISSIPATE AS IT REACHES THE COAST
MONDAY MORNING...GIVING A SLY BREEZE OVER THE COASTAL WATERS.
ANOTHER SYSTEM WILL BRING A BOUT OF STRONG ONSHORE FLOW TUESDAY
NIGHT...THEN EASING ON WEDNESDAY. THE REST OF THE WEEK WILL BE A
MORE SUMMERY WIND REGIME WITH A TYPICAL NW BREEZE EACH DAY. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
     THROUGH 1 AM PDT MONDAY.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML













000
FXUS66 KSEW 010334
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
834 PM PDT SUN AUG 31 2014

.SYNOPSIS...A WEAK UPPER LEVEL TROUGH CROSSING THE AREA WILL
MAINTAIN A CHANCE OF SHOWERS OVER THE CASCADES TONIGHT. THE
ASSOCIATED WEAK FRONT WILL BRING A CHANCE OF SHOWERS TO THE NORTH
COAST AND NORTH CASCADES LATE TONIGHT AND MONDAY. MOSTLY CLOUDY
SKIES WILL CONTINUE OVER THE REST OF WESTERN WASHINGTON. RAIN IS
LIKELY ON TUESDAY AS A VIGOROUS UPPER LEVEL TROUGH CROSSES THE
REGION. AN UPPER LEVEL RIDGE OFFSHORE WILL BRING A GRADUAL WARMING
AND DRYING PATTERN FROM WEDNESDAY THROUGH NEXT WEEKEND.

&&

.SHORT TERM...WATER VAPOR IMAGERY SHOWS A WEAK UPPER LEVEL SHORTWAVE
TROUGH ALONG THE B.C. COAST THAT WILL BRUSH PAST THE NORTH PART OF W
WA TONIGHT. THE WILL BRING A CHANCE OF SHOWERS TO THE CASCADES...BUT
MAINLY THE NORTH PART. IR AND VISIBLE SATELLITE IMAGERY SHOW A LOT
OF MID LEVEL CLOUDS JUST OFFSHORE THAT SHOULD SPREAD OVER W WA
OVERNIGHT...ALTHOUGH THE OLYMPICS MAY SHIELD THE PUGET SOUND REGION
A BIT. THE VERY WEAK SURFACE FRONT PRESENTLY ASSOCIATED WITH THE
UPPER TROUGH WILL GLIDE TO THE COAST LATE TONIGHT THEN FALL APART
MONDAY. A LITTLE LIGHT RAIN IS POSSIBLE FOR THE N COAST AND N
INTERIOR MONDAY AS THE FRONT DISSIPATES. THE PUGET SOUND REGION AND
SW INTERIOR WILL PROBABLY BE THE LEAST AFFECTED BY THE DISSIPATING
FRONT AND SO COULD SEE SOME PARTIAL SUNSHINE MONDAY AFTERNOON.

MODELS HAVE BEEN REASONABLY CONSISTENT WITH THE TIMING AND TRACK OF
THE VIGOROUS UPPER LEVEL TROUGH THAT IS EXPECTED TO CROSS THE AREA
ON TUESDAY. THIS TROUGH SHOWS UP NICELY ON WATER VAPOR IMAGERY OVER
THE GULF OF AK THIS EVENING...AND WILL MOVE SE ALONG THE B.C. COAST
THROUGH MONDAY NIGHT...ENDING UP OVER W WA ON TUESDAY. LATEST MODEL
TIMING HAS THE BEST CHANCE OF RAIN TUESDAY AFTERNOON. THE NAM IS THE
DRIEST MODEL WITH ONLY A FEW HUNDREDTHS OF AN INCH OF RAIN...WHILE
THE ECMWF IS WETTEST WITH 2 TO 4 TENTHS OVER THE NORTH. THIS IS A
FAIRLY DRY TRACK FOR THE TROUGH AND IT IS FAST MOVING...SO ACTUAL
RAINFALL ACCUMULATIONS WILL PROBABLY FALL IN-BETWEEN THE TWO MODELS.
THE TROUGH WILL DRAG MUCH COOLER AIR ALOFT OVER THE AREA TUESDAY
NIGHT WITH SNOW LEVELS OVER THE CASCADES DROPPING DOWN TO JUST ABOVE
6000 FEET AFTER MIDNIGHT. THERE COULD STILL BE SOME LIGHT SHOWERS
AROUND FOR A TINY BIT OF MOUNTAIN S.N.O.W.

THE UPPER LEVEL TROUGH WILL MOVE QUICKLY EAST TUESDAY
NIGHT...ALLOWING DRIER N FLOW ALOFT FROM AN OFFSHORE UPPER LEVEL
RIDGE TO MOVE OVER THE AREA. WELL DEVELOPED SW ONSHORE FLOW TUESDAY
NIGHT WILL KEEP THE LOWER AIR MASS MOIST WITH STRATUS THROUGH
WEDNESDAY MORNING. WITH DRY AIR ALOFT THE STRATUS SHOULD CLEAR OUT
BY AFTERNOON. WEDNESDAY SHOULD BE SLIGHTLY WARMER THAN TUESDAY...BUT
THE RESIDUAL COOL AIR MASS FROM THE UPPER TROUGH WILL CAP MAX TEMPS
IN THE 60S TO NEAR 70. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 334 PM AFD...MEDIUM RANGE
MODELS ALL AGREE ON THE ZONAL FLOW OVER THE NORTHEAST PACIFIC
BUCKLING INTO A HIGHER AMPLITUDE PATTERN BY MIDWEEK. THIS PATTERN
WILL BE ANCHORED BY A LARGE SCALE RIDGE THAT WILL BUILD ALONG 140W
TUESDAY AND INTO BRITISH COLUMBIA BY WEDNESDAY NIGHT. MODELS DO
DISAGREE ON THE FLOW DOWNSTREAM OF THE RIDGE ON FRIDAY WITH VARYING
DEGREES OF SPLIT FLOW ALOFT OVER THE NORTHWEST AND A WEAK UPPER
LEVEL LOW OVER THE GREAT BASIN OR CENTRAL ROCKY MOUNTAINS.
NONETHELESS THE LARGE SCALE PATTERN WILL KEEP THE PACIFIC NORTHWEST
DRIER AND WARMER BEGINNING WEDNESDAY AFTERNOON AND PERSISTING
THROUGH THE WEEKEND. MODELS GENERALLY AGREE ON A SYSTEM RIDING OVER
THE TOP RIDGE AND INTO THE NORTHWEST LATE SUNDAY INTO MONDAY
MORNING.

&&

.AVIATION...LIGHT NW FLOW ALOFT OVER THE REGION THROUGH MONDAY.
LIGHT LOW LEVEL ONSHORE FLOW. A WEAK TROUGH WILL DISSIPATE AS IT
REACHES THE COAST MONDAY MORNING. THE AIR MASS IS GENERALLY MOIST
AND STABLE...EXCEPT WEAKLY UNSTABLE MONDAY AFTERNOON. ONLY A SLIGHT
CHANCE OF A FEW SHOWERS...MAINLY N OF SEATTLE ON MONDAY AFTERNOON.
AN MVFR CEILING IS EXPECTED TO FORM OVER SOME PARTS OF THE AREA LATE
TONIGHT AND MONDAY MORNING...LIFTING AND SCATTERING BY 18Z.

KSEA...LIGHT WIND...BECOMING S-SW TO 5 KNOTS LATE TONIGHT AND
MONDAY. MVFR CIGS ARE LIKELY TO FORM AFTER MIDNIGHT...THEN LIFT AND
SCATTER BY 18Z. DTM

&&

.MARINE...A WEAK SYSTEM WILL DISSIPATE AS IT REACHES THE COAST
MONDAY MORNING...GIVING A SLY BREEZE OVER THE COASTAL WATERS.
ANOTHER SYSTEM WILL BRING A BOUT OF STRONG ONSHORE FLOW TUESDAY
NIGHT...THEN EASING ON WEDNESDAY. THE REST OF THE WEEK WILL BE A
MORE SUMMERY WIND REGIME WITH A TYPICAL NW BREEZE EACH DAY. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
     THROUGH 1 AM PDT MONDAY.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML














000
FXUS66 KSEW 312236
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
334 PM PDT SUN AUG 31 2014

.SYNOPSIS...STRONG WESTERLY FLOW ALOFT OVER THE AREA WILL HELP KEEP
LINGERING SHOWERS OVER THE CASCADES THIS EVENING. A WEAK SYSTEM THAT
WILL BRUSH THE AREA FROM THE NORTH WILL BRING A CHANCE OF LIGHT RAIN
TO THE COAST LATE TONIGHT...THEN THE NORTH DURING THE MORNING AND
AFTERNOON HOURS ON LABOR DAY. HIGH PRESSURE ALOFT WILL BUILD BRIEFLY
OVER WESTERN WASHINGTON IN THE AFTERNOON AND EVENING...FOLLOWED BY A
STRONGER AND COLDER SYSTEM THAT WILL IMPACT THE AREA ON TUESDAY.
RISING UPPER LEVEL HEIGHTS WEDNESDAY WILL USHER IN A DRIER AND
WARMER PERIOD THAT WILL PERSIST THROUGH THE WEEKEND.

&&

.SHORT TERM...THE UPPER LEVEL JET AND STRONG WESTERLY FLOW ALOFT
WILL KEEP THE THREAT OF SHOWERS MAINLY OVER THE CASCADES TONIGHT AS
HEIGHTS RISE BRIEFLY OVER THE REGION AHEAD OF A WEAK SYSTEM THAT
WILL BRUSH THE AREA FROM THE NORTH LATE TONIGHT INTO MONDAY MORNING.
MODELS CONTINUE TO SHOW THIS SYSTEM ALL BUT FALL APART AS IT MOVES
INTO HAIDA GUAII AND BRITISH COLUMBIA THIS EVENING. HAVE BACKED OFF
ON PRECIPITATION THIS EVENING FOR THE AREA WITH A CHANCE OF RAIN
MAINLY FOR THE NORTH COAST AFTER MIDNIGHT AS THE TAIL END OF THE
WEAK FRONT APPROACHES FROM THE WEST. ESSENTIALLY ALL MODELS SHOW
THIS BOUNDARY COMPLETELY COLLAPSE AS IT MOVES ONSHORE...BRUSHING THE
NORTH WITH LIMITED PRECIPITATION THROUGH THE MORNING AND INTO THE
AFTERNOON. OTHERWISE EXPECT MORNING CLOUDS TO GIVE WAY TO PARTLY
SUNNY AND DRY SKIES WITH NEAR NORMAL TEMPERATURES.

MODELS REMAIN IN GOOD AGREEMENT ON THE NEXT SYSTEM...EJECTING A
VIGOROUS SHORTWAVE TROUGH FROM CENTRAL ALASKA INTO THE GULF OF
ALASKA EARLY LABOR DAY MORNING. THIS SYSTEM IS FORECAST TO DIG SOUTH
AND EAST ALONG THE BRITISH COLUMBIA COAST MONDAY AND MONDAY NIGHT
BEFORE REACHING WASHINGTON TUESDAY MORNING. THE BEST CHANCE OF
PRECIPITATION WILL BE ACROSS THE NORTHERN HALF OF THE AREA WITH MUCH
COOLER TEMPERATURES. DAYTIME TEMPS WILL RUN 5-10 DEGREES COOLER THAN
MONDAY WHILE SNOW LEVELS WILL FALL TO JUST BELOW 6000 FEET LATE
TUESDAY NIGHT AND EARLY WEDNESDAY MORNING OVER THE NORTH CASCADES.
LOCALLY BREEZY CONDITIONS ARE POSSIBLE TUESDAY AFTERNOON.


.LONG TERM...MEDIUM RANGE MODELS ALL AGREE ON THE ZONAL FLOW OVER
THE NORTHEAST PACIFIC BUCKLING INTO A HIGHER AMPLITUDE PATTERN BY
MIDWEEK. THIS PATTERN WILL BE ANCHORED BY A LARGE SCALE RIDGE THAT
WILL BUILD ALONG 140W TUESDAY AND INTO BRITISH COLUMBIA BY WEDNESDAY
NIGHT. MODELS DO DISAGREE ON THE FLOW DOWNSTREAM OF THE RIDGE ON
FRIDAY WITH VARYING DEGREES OF SPLIT FLOW ALOFT OVER THE NORTHWEST
AND A WEAK UPPER LEVEL LOW OVER THE GREAT BASIN OR CENTRAL ROCKY
MOUNTAINS. NONETHELESS THE LARGE SCALE PATTERN WILL KEEP THE PACIFIC
NORTHWEST DRIER AND WARMER BEGINNING WEDNESDAY AFTERNOON AND
PERSISTING THROUGH THE WEEKEND. MODELS GENERALLY AGREE ON A SYSTEM
RIDING OVER THE TOP RIDGE AND INTO THE NORTHWEST LATE SUNDAY INTO
MONDAY MORNING.

&&

.AVIATION...NW FLOW ALOFT. LIGHT LOW LEVEL ONSHORE FLOW. AIR IS
MOIST. A WEAK WEATHER SYSTEM WILL DISSIPATE AS IT REACHES THE WA
COAST MONDAY. LIGHT ISOLATED SHOWERS FROM AFTERNOON CUMULUS WILL
GIVE WAY TO AREAS OF FAIRLY LOW STRATUS OVERNIGHT. MORNING LOW
CLOUDS ON MONDAY WILL LIFT INTO THE AFTERNOON AND SOME MOISTURE
ARRIVES WITH THE NEXT WEAK SYSTEM.

KSEA...AFTER SOME CLEARING THROUGH THIS EVENING LOW CLOUDS WILL
DEVELOP OVERNIGHT FOR ANOTHER CLOUDY MORNING ON MONDAY.

&&

.MARINE...A WEAK SYSTEM WILL DISSIPATE AS IT REACHES THE COAST
MONDAY...GIVING A SLY BREEZE OVER THE COASTAL WATERS. THEN BY THE
MIDDLE OF THE WEEK A MORE SUMMERY WIND REGIME WILL SET UP WITH A
TYPICAL NW BREEZE EACH DAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 312236
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
334 PM PDT SUN AUG 31 2014

.SYNOPSIS...STRONG WESTERLY FLOW ALOFT OVER THE AREA WILL HELP KEEP
LINGERING SHOWERS OVER THE CASCADES THIS EVENING. A WEAK SYSTEM THAT
WILL BRUSH THE AREA FROM THE NORTH WILL BRING A CHANCE OF LIGHT RAIN
TO THE COAST LATE TONIGHT...THEN THE NORTH DURING THE MORNING AND
AFTERNOON HOURS ON LABOR DAY. HIGH PRESSURE ALOFT WILL BUILD BRIEFLY
OVER WESTERN WASHINGTON IN THE AFTERNOON AND EVENING...FOLLOWED BY A
STRONGER AND COLDER SYSTEM THAT WILL IMPACT THE AREA ON TUESDAY.
RISING UPPER LEVEL HEIGHTS WEDNESDAY WILL USHER IN A DRIER AND
WARMER PERIOD THAT WILL PERSIST THROUGH THE WEEKEND.

&&

.SHORT TERM...THE UPPER LEVEL JET AND STRONG WESTERLY FLOW ALOFT
WILL KEEP THE THREAT OF SHOWERS MAINLY OVER THE CASCADES TONIGHT AS
HEIGHTS RISE BRIEFLY OVER THE REGION AHEAD OF A WEAK SYSTEM THAT
WILL BRUSH THE AREA FROM THE NORTH LATE TONIGHT INTO MONDAY MORNING.
MODELS CONTINUE TO SHOW THIS SYSTEM ALL BUT FALL APART AS IT MOVES
INTO HAIDA GUAII AND BRITISH COLUMBIA THIS EVENING. HAVE BACKED OFF
ON PRECIPITATION THIS EVENING FOR THE AREA WITH A CHANCE OF RAIN
MAINLY FOR THE NORTH COAST AFTER MIDNIGHT AS THE TAIL END OF THE
WEAK FRONT APPROACHES FROM THE WEST. ESSENTIALLY ALL MODELS SHOW
THIS BOUNDARY COMPLETELY COLLAPSE AS IT MOVES ONSHORE...BRUSHING THE
NORTH WITH LIMITED PRECIPITATION THROUGH THE MORNING AND INTO THE
AFTERNOON. OTHERWISE EXPECT MORNING CLOUDS TO GIVE WAY TO PARTLY
SUNNY AND DRY SKIES WITH NEAR NORMAL TEMPERATURES.

MODELS REMAIN IN GOOD AGREEMENT ON THE NEXT SYSTEM...EJECTING A
VIGOROUS SHORTWAVE TROUGH FROM CENTRAL ALASKA INTO THE GULF OF
ALASKA EARLY LABOR DAY MORNING. THIS SYSTEM IS FORECAST TO DIG SOUTH
AND EAST ALONG THE BRITISH COLUMBIA COAST MONDAY AND MONDAY NIGHT
BEFORE REACHING WASHINGTON TUESDAY MORNING. THE BEST CHANCE OF
PRECIPITATION WILL BE ACROSS THE NORTHERN HALF OF THE AREA WITH MUCH
COOLER TEMPERATURES. DAYTIME TEMPS WILL RUN 5-10 DEGREES COOLER THAN
MONDAY WHILE SNOW LEVELS WILL FALL TO JUST BELOW 6000 FEET LATE
TUESDAY NIGHT AND EARLY WEDNESDAY MORNING OVER THE NORTH CASCADES.
LOCALLY BREEZY CONDITIONS ARE POSSIBLE TUESDAY AFTERNOON.


.LONG TERM...MEDIUM RANGE MODELS ALL AGREE ON THE ZONAL FLOW OVER
THE NORTHEAST PACIFIC BUCKLING INTO A HIGHER AMPLITUDE PATTERN BY
MIDWEEK. THIS PATTERN WILL BE ANCHORED BY A LARGE SCALE RIDGE THAT
WILL BUILD ALONG 140W TUESDAY AND INTO BRITISH COLUMBIA BY WEDNESDAY
NIGHT. MODELS DO DISAGREE ON THE FLOW DOWNSTREAM OF THE RIDGE ON
FRIDAY WITH VARYING DEGREES OF SPLIT FLOW ALOFT OVER THE NORTHWEST
AND A WEAK UPPER LEVEL LOW OVER THE GREAT BASIN OR CENTRAL ROCKY
MOUNTAINS. NONETHELESS THE LARGE SCALE PATTERN WILL KEEP THE PACIFIC
NORTHWEST DRIER AND WARMER BEGINNING WEDNESDAY AFTERNOON AND
PERSISTING THROUGH THE WEEKEND. MODELS GENERALLY AGREE ON A SYSTEM
RIDING OVER THE TOP RIDGE AND INTO THE NORTHWEST LATE SUNDAY INTO
MONDAY MORNING.

&&

.AVIATION...NW FLOW ALOFT. LIGHT LOW LEVEL ONSHORE FLOW. AIR IS
MOIST. A WEAK WEATHER SYSTEM WILL DISSIPATE AS IT REACHES THE WA
COAST MONDAY. LIGHT ISOLATED SHOWERS FROM AFTERNOON CUMULUS WILL
GIVE WAY TO AREAS OF FAIRLY LOW STRATUS OVERNIGHT. MORNING LOW
CLOUDS ON MONDAY WILL LIFT INTO THE AFTERNOON AND SOME MOISTURE
ARRIVES WITH THE NEXT WEAK SYSTEM.

KSEA...AFTER SOME CLEARING THROUGH THIS EVENING LOW CLOUDS WILL
DEVELOP OVERNIGHT FOR ANOTHER CLOUDY MORNING ON MONDAY.

&&

.MARINE...A WEAK SYSTEM WILL DISSIPATE AS IT REACHES THE COAST
MONDAY...GIVING A SLY BREEZE OVER THE COASTAL WATERS. THEN BY THE
MIDDLE OF THE WEEK A MORE SUMMERY WIND REGIME WILL SET UP WITH A
TYPICAL NW BREEZE EACH DAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML










000
FXUS66 KSEW 311616
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
914 AM PDT SUN AUG 31 2014

.SYNOPSIS...STRONG WESTERLY FLOW ALOFT OVER THE AREA WILL KEEP THE
WEATHER SOMEWHAT UNSETTLED TODAY. A LOW PRESSURE SYSTEM PASSING TO
OUR NORTH WILL RESULT IN A CHANCE OF LIGHT RAIN LATE TONIGHT FOR THE
COAST AND MONDAY MORNING OVER THE NORTH. HIGH PRESSURE ALOFT WILL
BUILD OVER THE REGION DURING THE AFTERNOON AND EVENING OF LABOR DAY
FOLLOWED BY A STRONGER AND COLDER SYSTEM TO IMPACT THE AREA ON
TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL JET AND STRONG WESTERLY FLOW OVER THE
REGION TODAY WILL KEEP THE THREAT OF SHOWERS IN THE FORECAST TODAY.

MODELS REMAIN IN AGREEMENT ON BRINGING A VIGOROUS SHORT WAVE TROUGH
INTO FAR NORTHERN BRITISH COLUMBIA AND BUILDING HEIGHTS OVER THE
PACIFIC NORTHWEST TONIGHT. HAVE GONE AHEAD AND UPDATED THE FORECAST
TO TAKE OUT THE THREAT OF PRECIPITATION OVER ALL BUT THE NORTH COAST
AND MOUNTAINS TONIGHT...AND THE NORTH TOMORROW MORNING. OTHERWISE
AND ELSEWHERE...LABOR DAY WILL BE A DRY DAY WITH NEAR NORMAL TEMPS
UNDER HIGH PRESSURE ALOFT.

MODELS CONTINUE TO BRING A STRONGER AND COLDER LOW PRESSURE SYSTEM
SOUTH THROUGH BRITISH COLUMBIA MONDAY...AND INTO WASHINGTON
TUESDAY. THE BEST CHANCE OF PRECIP WILL BE ACROSS THE NORTHERN
ZONES. THE MOST NOTICEABLE IMPACTS WITH THIS SYSTEM WILL BE MUCH
COOLER TEMPERATURES...DAYTIME TEMPS WILL RUN 5-10 DEGREES COOLER
THAN MONDAY. ACCORDINGLY...THE SNOW LEVEL IS EXPECTED TO FALL TO
BELOW 6000 FEET LATE TUESDAY NIGHT IN THE NORTH CASCADES...A
RAIN/SNOW MIX AT THOSE ELEVATIONS WILL NOT BE SURPRISING. LOCALLY
BREEZY CONDITIONS ARE POSSIBLE TUESDAY AFTERNOON.


.LONG TERM...FROM PREVIOUS DISCUSSION...AN UPPER RIDGE WILL BUILD
OVER THE REGION ON WED FOR THE ESTABLISHMENT OF DRY...NORTHERLY
FLOW. WED NIGHT WILL LIKELY BE THE CHILLIEST MORNING THIS
WEEK...WITH THE MIN TEMP AT MANY LOWLAND SITES PREDICTED TO BE IN
THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...NW FLOW ALOFT. LOW LEVEL ONSHORE FLOW. AIR IS MOIST. A
WEAK WEATHER SYSTEM WILL MOVE INTO WRN WA MONDAY. ISOLATED SHOWERS.
AREAS OF MORNING LOW CLOUDS WILL LIFT INTO THE AFTERNOON WITH
INCREASING SUNBREAKS.

KSEA...MORNING CLOUDS WILL LIFT WITH INCREASING SUNBREAKS INTO THE
AFTERNOON WITH THE DAYTIME HEATING...BUT THE AIR IS MOIST AND LOW
CLOUDS WILL DEVELOP AGAIN TONIGHT FOR ANOTHER CLOUDY MORNING ON
MONDAY.

&&

.MARINE...NO UPDATES OR CHANGES EXPECTED TO THE FORECAST THIS
MORNING. A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML








000
FXUS66 KSEW 311616
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
914 AM PDT SUN AUG 31 2014

.SYNOPSIS...STRONG WESTERLY FLOW ALOFT OVER THE AREA WILL KEEP THE
WEATHER SOMEWHAT UNSETTLED TODAY. A LOW PRESSURE SYSTEM PASSING TO
OUR NORTH WILL RESULT IN A CHANCE OF LIGHT RAIN LATE TONIGHT FOR THE
COAST AND MONDAY MORNING OVER THE NORTH. HIGH PRESSURE ALOFT WILL
BUILD OVER THE REGION DURING THE AFTERNOON AND EVENING OF LABOR DAY
FOLLOWED BY A STRONGER AND COLDER SYSTEM TO IMPACT THE AREA ON
TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL JET AND STRONG WESTERLY FLOW OVER THE
REGION TODAY WILL KEEP THE THREAT OF SHOWERS IN THE FORECAST TODAY.

MODELS REMAIN IN AGREEMENT ON BRINGING A VIGOROUS SHORT WAVE TROUGH
INTO FAR NORTHERN BRITISH COLUMBIA AND BUILDING HEIGHTS OVER THE
PACIFIC NORTHWEST TONIGHT. HAVE GONE AHEAD AND UPDATED THE FORECAST
TO TAKE OUT THE THREAT OF PRECIPITATION OVER ALL BUT THE NORTH COAST
AND MOUNTAINS TONIGHT...AND THE NORTH TOMORROW MORNING. OTHERWISE
AND ELSEWHERE...LABOR DAY WILL BE A DRY DAY WITH NEAR NORMAL TEMPS
UNDER HIGH PRESSURE ALOFT.

MODELS CONTINUE TO BRING A STRONGER AND COLDER LOW PRESSURE SYSTEM
SOUTH THROUGH BRITISH COLUMBIA MONDAY...AND INTO WASHINGTON
TUESDAY. THE BEST CHANCE OF PRECIP WILL BE ACROSS THE NORTHERN
ZONES. THE MOST NOTICEABLE IMPACTS WITH THIS SYSTEM WILL BE MUCH
COOLER TEMPERATURES...DAYTIME TEMPS WILL RUN 5-10 DEGREES COOLER
THAN MONDAY. ACCORDINGLY...THE SNOW LEVEL IS EXPECTED TO FALL TO
BELOW 6000 FEET LATE TUESDAY NIGHT IN THE NORTH CASCADES...A
RAIN/SNOW MIX AT THOSE ELEVATIONS WILL NOT BE SURPRISING. LOCALLY
BREEZY CONDITIONS ARE POSSIBLE TUESDAY AFTERNOON.


.LONG TERM...FROM PREVIOUS DISCUSSION...AN UPPER RIDGE WILL BUILD
OVER THE REGION ON WED FOR THE ESTABLISHMENT OF DRY...NORTHERLY
FLOW. WED NIGHT WILL LIKELY BE THE CHILLIEST MORNING THIS
WEEK...WITH THE MIN TEMP AT MANY LOWLAND SITES PREDICTED TO BE IN
THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...NW FLOW ALOFT. LOW LEVEL ONSHORE FLOW. AIR IS MOIST. A
WEAK WEATHER SYSTEM WILL MOVE INTO WRN WA MONDAY. ISOLATED SHOWERS.
AREAS OF MORNING LOW CLOUDS WILL LIFT INTO THE AFTERNOON WITH
INCREASING SUNBREAKS.

KSEA...MORNING CLOUDS WILL LIFT WITH INCREASING SUNBREAKS INTO THE
AFTERNOON WITH THE DAYTIME HEATING...BUT THE AIR IS MOIST AND LOW
CLOUDS WILL DEVELOP AGAIN TONIGHT FOR ANOTHER CLOUDY MORNING ON
MONDAY.

&&

.MARINE...NO UPDATES OR CHANGES EXPECTED TO THE FORECAST THIS
MORNING. A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML







000
FXUS66 KSEW 311116 CCA
AFDSEW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
416 AM PDT SUN AUG 31 2014

CORRECTED A COUPLE OF TYPOS IN THE SHORT TERM SEGMENT.

.SYNOPSIS...WEAK DISTURBANCES EMBEDDED IN THE STRONG WESTERLY FLOW
ALOFT OVER THE AREA WILL KEEP THE WEATHER SOMEWHAT UNSETTLED
TODAY. A LOW PRESSURE SYSTEM PASSING TO OUR NORTH WILL RESULT IN
A CHANCE OF LIGHT RAIN TONIGHT. HIGH PRESSURE ALOFT WILL PREVAIL
OVER THE REGION ON LABOR DAY. LOOK FOR A STRONGER AND COLDER
SYSTEM TO IMPACT THE AREA ON TUESDAY.

&&

.SHORT TERM...
AN UPPER JET WILL REMAIN DRAPED OVER THE REGION TODAY. POORLY
DEFINED AND FAST-MOVING DISTURBANCES EMBEDDED IN THE FLOW WILL
RESULT IN SOME INSTABILITY SHOWERS OVER THE CWA...HENCE THE CHANCE
POPS.

THE MODELS WERE IN AGREEMENT IN TAKING THE VIGOROUS SHORT WAVE
TROF...PRESENTLY NEAR THE GULF OF AK...ACROSS BRITISH COLUMBIA
TONIGHT. THE UPPER JET WILL LIFT NORTHWARD TONIGHT...ALLOWING
HEIGHTS/THICKNESSES TO BUILD OVER THE AREA. HESITATED TO COMPLETELY
REMOVE POPS FROM THE TONIGHT FORECAST SINCE IT IS CONCEIVABLE THAT
THERE COULD BE SOME SPOTTY LIGHT PRECIP DUE TO WARM AIR ADVECTION.

THERE MIGHT BE SOME SPOTTY LIGHT RAIN OR DRIZZLE OVER THE NORTHWEST
PART OF THE CWA MON MORNING...OTHERWISE LABOR DAY WILL BE A DRY DAY
WITH NEAR NORMAL TEMPS UNDER HIGH PRESSURE ALOFT.

A STRONGER AND COLDER LOW PRESSURE SYSTEM WILL IMPACT THE REGION
ON SUNDAY. THE BEST CHANCE OF PRECIP WILL BE ACROSS THE NORTHERN
ZONES. DAYTIME TEMPS ON TUE SHOULD BE 5-10 DEGREES COOLER THAN
MON. ALTHOUGH THE MODELS DID NOT INDICATE IT...WOULD NOT BE
SURPRISED IF IT BECOMES LOCALLY BREEZY IN THE AFTERNOON.

THE SNOW LEVEL IS EXPECTED TO FALL TO NEAR 5500 FEET LATE SUNDAY
NIGHT IN THE NORTH CASCADES...THUS DO NOT BE SURPRISED TO SEE A
RAIN/SNOW MIX AT THIS ELEVATION LATE SUNDAY NIGHT.

.LONG TERM...
AN UPPER RIDGE WILL BUILD OVER THE REGION ON WED FOR THE
ESTABLISHMENT OF DRY...NORTHERLY FLOW. WED NIGHT WILL LIKELY BE
THE CHILLIEST MORNING THIS WEEK...WITH THE MIN TEMP AT MANY
LOWLAND SITES PREDICTED TO BE IN THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...LIGHT NW FLOW ALOFT TODAY BETWEEN WEATHER SYSTEMS. A
WEAK WEATHER SYSTEM WILL DISSIPATE AS IT MOVES INTO THE AREA ON
MONDAY.  MOIST AND WEAKLY UNSTABLE ATMOSPHERE. ISOLATED SHOWERS.
AREAS OF MVFR CIGS EXPECTED THIS MORNING. CLOUDS SHOULD LIFT AND
SCATTER BY MIDDAY.

KSEA...MVFR CIGS THIS MORNING...LIFTING ABOVE 3K FT AND SCATTERING
BY AROUND 18Z. S-SW WIND 4-8 KT BECOMING NLY FOR A FEW HOURS THIS
EVENING. A PUGET SOUND CONVERGENCE ZONE MAY REFORM AND PRODUCE
ADDITIONAL SHOWERS LATE THIS AFTERNOON AND EVENING...OTHERWISE JUST
ISOLATED SHOWER ACTIVITY.

&&

.MARINE...A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 311116 CCA
AFDSEW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
416 AM PDT SUN AUG 31 2014

CORRECTED A COUPLE OF TYPOS IN THE SHORT TERM SEGMENT.

.SYNOPSIS...WEAK DISTURBANCES EMBEDDED IN THE STRONG WESTERLY FLOW
ALOFT OVER THE AREA WILL KEEP THE WEATHER SOMEWHAT UNSETTLED
TODAY. A LOW PRESSURE SYSTEM PASSING TO OUR NORTH WILL RESULT IN
A CHANCE OF LIGHT RAIN TONIGHT. HIGH PRESSURE ALOFT WILL PREVAIL
OVER THE REGION ON LABOR DAY. LOOK FOR A STRONGER AND COLDER
SYSTEM TO IMPACT THE AREA ON TUESDAY.

&&

.SHORT TERM...
AN UPPER JET WILL REMAIN DRAPED OVER THE REGION TODAY. POORLY
DEFINED AND FAST-MOVING DISTURBANCES EMBEDDED IN THE FLOW WILL
RESULT IN SOME INSTABILITY SHOWERS OVER THE CWA...HENCE THE CHANCE
POPS.

THE MODELS WERE IN AGREEMENT IN TAKING THE VIGOROUS SHORT WAVE
TROF...PRESENTLY NEAR THE GULF OF AK...ACROSS BRITISH COLUMBIA
TONIGHT. THE UPPER JET WILL LIFT NORTHWARD TONIGHT...ALLOWING
HEIGHTS/THICKNESSES TO BUILD OVER THE AREA. HESITATED TO COMPLETELY
REMOVE POPS FROM THE TONIGHT FORECAST SINCE IT IS CONCEIVABLE THAT
THERE COULD BE SOME SPOTTY LIGHT PRECIP DUE TO WARM AIR ADVECTION.

THERE MIGHT BE SOME SPOTTY LIGHT RAIN OR DRIZZLE OVER THE NORTHWEST
PART OF THE CWA MON MORNING...OTHERWISE LABOR DAY WILL BE A DRY DAY
WITH NEAR NORMAL TEMPS UNDER HIGH PRESSURE ALOFT.

A STRONGER AND COLDER LOW PRESSURE SYSTEM WILL IMPACT THE REGION
ON SUNDAY. THE BEST CHANCE OF PRECIP WILL BE ACROSS THE NORTHERN
ZONES. DAYTIME TEMPS ON TUE SHOULD BE 5-10 DEGREES COOLER THAN
MON. ALTHOUGH THE MODELS DID NOT INDICATE IT...WOULD NOT BE
SURPRISED IF IT BECOMES LOCALLY BREEZY IN THE AFTERNOON.

THE SNOW LEVEL IS EXPECTED TO FALL TO NEAR 5500 FEET LATE SUNDAY
NIGHT IN THE NORTH CASCADES...THUS DO NOT BE SURPRISED TO SEE A
RAIN/SNOW MIX AT THIS ELEVATION LATE SUNDAY NIGHT.

.LONG TERM...
AN UPPER RIDGE WILL BUILD OVER THE REGION ON WED FOR THE
ESTABLISHMENT OF DRY...NORTHERLY FLOW. WED NIGHT WILL LIKELY BE
THE CHILLIEST MORNING THIS WEEK...WITH THE MIN TEMP AT MANY
LOWLAND SITES PREDICTED TO BE IN THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...LIGHT NW FLOW ALOFT TODAY BETWEEN WEATHER SYSTEMS. A
WEAK WEATHER SYSTEM WILL DISSIPATE AS IT MOVES INTO THE AREA ON
MONDAY.  MOIST AND WEAKLY UNSTABLE ATMOSPHERE. ISOLATED SHOWERS.
AREAS OF MVFR CIGS EXPECTED THIS MORNING. CLOUDS SHOULD LIFT AND
SCATTER BY MIDDAY.

KSEA...MVFR CIGS THIS MORNING...LIFTING ABOVE 3K FT AND SCATTERING
BY AROUND 18Z. S-SW WIND 4-8 KT BECOMING NLY FOR A FEW HOURS THIS
EVENING. A PUGET SOUND CONVERGENCE ZONE MAY REFORM AND PRODUCE
ADDITIONAL SHOWERS LATE THIS AFTERNOON AND EVENING...OTHERWISE JUST
ISOLATED SHOWER ACTIVITY.

&&

.MARINE...A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML







000
FXUS66 KSEW 311029
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
329 AM PDT SUN AUG 31 2014

.SYNOPSIS...WEAK DISTURBANCES EMBEDDED IN THE STRONG WESTERLY FLOW
ALOFT OVER THE AREA WILL KEEP THE WEATHER SOMEWHAT UNSETTLED
TODAY. A LOW PRESSURE SYSTEM PASSING TO OUR NORTH WILL RESULT IN
A CHANCE OF LIGHT RAIN TONIGHT. HIGH PRESSURE ALOFT WILL PREVAIL
OVER THE REGION ON LABOR DAY. LOOK FOR A STRONGER AND COLDER
SYSTEM TO IMPACT THE AREA ON TUESDAY.

&&

.SHORT TERM...
AN UPPER JET WILL REMAIN DRAPED OVER THE REGION TODAY. POORLY
DEFINED AND FAST-MOVING DISTURBANCES EMBEDDED IN THE FLOW WILL
RESULT IN SOME INSTABILITY SHOWERS OVER THE CWA...HENCE THE CHANCE
POPS.

THE MODELS WERE IN AGREEMENT IN TAKING THE VIGOROUS SHORT TROF...
PRESENTLY NEAR THE GULF OF AK...ACROSS BRITISH COLUMBIA TONIGHT.
THE UPPER JET WILL LIFT NORTHWARD TONIGHT...ALLOWING
HEIGHTS/THICKNESSES TO BUILD OVER THE AREA. HESITATED TO
COMPLETELY REMOVE POPS FROM THE TONIGHT FORECAST SINCE IT IS
CONCEIVABLE THAT THERE COULD BE SOME SPOTTY LIGHT PRECIP DUE TO
WARM AIR ADVECTION.

THERE MIGHT BE SOME SPOTTY LIGHT RAIN OR DRIZZLE OVER THE
NORTHWEST PART OF THE CWA MON MORNING...OTHERWISE LABOR DAY WILL
BE A DRY DAY WITH NEAR NORMAL TEMPS UNDER HIGH PRESSURE ALOFT.

A STRONGER AND COLDER LOW PRESSURE SYSTEM WILL IMPACT THE REGION
ON SUNDAY. THE BEST CHANCE OF SHOWERS WILL BE ACROSS THE NORTHERN
ZONES. DAYTIME TEMPS ON TUE SHOULD BE 5-10 DEGREES COOLER THAN
MON. ALTHOUGH THE MODELS DID NOT INDICATE IT...WOULD NOT BE
SURPRISED IF IT BECOMES LOCALLY BREEZY IN THE AFTERNOON.

THE SNOW LEVEL IS EXPECTED TO FALL TO NEAR 5500 FEET LATE SUNDAY
NIGHT IN THE NORTH CASCADES...THUS DO NOT BE SURPRISED TO SEE A
RAIN/SNOW MIX AT THIS ELEVATION LATE SUNDAY NIGHT.

.LONG TERM...
AN UPPER RIDGE WILL BUILD OVER THE REGION ON WED FOR THE
ESTABLISHMENT OF DRY...NORTHERLY FLOW. WED NIGHT WILL LIKELY BE
THE CHILLIEST MORNING THIS WEEK...WITH THE MIN TEMP AT MANY
LOWLAND SITES PREDICTED TO BE IN THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...LIGHT NW FLOW ALOFT TODAY BETWEEN WEATHER SYSTEMS. A
WEAK WEATHER SYSTEM WILL DISSIPATE AS IT MOVES INTO THE AREA ON
MONDAY.  MOIST AND WEAKLY UNSTABLE ATMOSPHERE. ISOLATED SHOWERS.
AREAS OF MVFR CIGS EXPECTED THIS MORNING. CLOUDS SHOULD LIFT AND
SCATTER BY MIDDAY.

KSEA...MVFR CIGS THIS MORNING...LIFTING ABOVE 3K FT AND SCATTERING
BY AROUND 18Z. S-SW WIND 4-8 KT BECOMING NLY FOR A FEW HOURS THIS
EVENING. A PUGET SOUND CONVERGENCE ZONE MAY REFORM AND PRODUCE
ADDITIONAL SHOWERS LATE THIS AFTERNOON AND EVENING...OTHERWISE JUST
ISOLATED SHOWER ACTIVITY.

&&

.MARINE...A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 311029
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
329 AM PDT SUN AUG 31 2014

.SYNOPSIS...WEAK DISTURBANCES EMBEDDED IN THE STRONG WESTERLY FLOW
ALOFT OVER THE AREA WILL KEEP THE WEATHER SOMEWHAT UNSETTLED
TODAY. A LOW PRESSURE SYSTEM PASSING TO OUR NORTH WILL RESULT IN
A CHANCE OF LIGHT RAIN TONIGHT. HIGH PRESSURE ALOFT WILL PREVAIL
OVER THE REGION ON LABOR DAY. LOOK FOR A STRONGER AND COLDER
SYSTEM TO IMPACT THE AREA ON TUESDAY.

&&

.SHORT TERM...
AN UPPER JET WILL REMAIN DRAPED OVER THE REGION TODAY. POORLY
DEFINED AND FAST-MOVING DISTURBANCES EMBEDDED IN THE FLOW WILL
RESULT IN SOME INSTABILITY SHOWERS OVER THE CWA...HENCE THE CHANCE
POPS.

THE MODELS WERE IN AGREEMENT IN TAKING THE VIGOROUS SHORT TROF...
PRESENTLY NEAR THE GULF OF AK...ACROSS BRITISH COLUMBIA TONIGHT.
THE UPPER JET WILL LIFT NORTHWARD TONIGHT...ALLOWING
HEIGHTS/THICKNESSES TO BUILD OVER THE AREA. HESITATED TO
COMPLETELY REMOVE POPS FROM THE TONIGHT FORECAST SINCE IT IS
CONCEIVABLE THAT THERE COULD BE SOME SPOTTY LIGHT PRECIP DUE TO
WARM AIR ADVECTION.

THERE MIGHT BE SOME SPOTTY LIGHT RAIN OR DRIZZLE OVER THE
NORTHWEST PART OF THE CWA MON MORNING...OTHERWISE LABOR DAY WILL
BE A DRY DAY WITH NEAR NORMAL TEMPS UNDER HIGH PRESSURE ALOFT.

A STRONGER AND COLDER LOW PRESSURE SYSTEM WILL IMPACT THE REGION
ON SUNDAY. THE BEST CHANCE OF SHOWERS WILL BE ACROSS THE NORTHERN
ZONES. DAYTIME TEMPS ON TUE SHOULD BE 5-10 DEGREES COOLER THAN
MON. ALTHOUGH THE MODELS DID NOT INDICATE IT...WOULD NOT BE
SURPRISED IF IT BECOMES LOCALLY BREEZY IN THE AFTERNOON.

THE SNOW LEVEL IS EXPECTED TO FALL TO NEAR 5500 FEET LATE SUNDAY
NIGHT IN THE NORTH CASCADES...THUS DO NOT BE SURPRISED TO SEE A
RAIN/SNOW MIX AT THIS ELEVATION LATE SUNDAY NIGHT.

.LONG TERM...
AN UPPER RIDGE WILL BUILD OVER THE REGION ON WED FOR THE
ESTABLISHMENT OF DRY...NORTHERLY FLOW. WED NIGHT WILL LIKELY BE
THE CHILLIEST MORNING THIS WEEK...WITH THE MIN TEMP AT MANY
LOWLAND SITES PREDICTED TO BE IN THE 40S.

EXPECT AN UPPER RIDGE TO DOMINATE THE WEATHER PATTERN OVER THE
AREA DURING MUCH OF THIS PERIOD. HOWEVER THE MEDIUM RANGE
SOLUTIONS DIFFERED ON THE STRENGTH OF THE RIDGE. BEYOND FRI...
CONFIDENCE IN THE FORECAST WAS LOW DUE TO DIFFERENCES IN THE
MEDIUM RANGE SOLUTIONS...THAT IS AN UPPER TROF VERSUS AN UPPER
RIDGE. THE ONLY CHANGES MADE WERE TO BLEND BETTER WITH
NEIGHBORING OFFICES.

&&

.AVIATION...LIGHT NW FLOW ALOFT TODAY BETWEEN WEATHER SYSTEMS. A
WEAK WEATHER SYSTEM WILL DISSIPATE AS IT MOVES INTO THE AREA ON
MONDAY.  MOIST AND WEAKLY UNSTABLE ATMOSPHERE. ISOLATED SHOWERS.
AREAS OF MVFR CIGS EXPECTED THIS MORNING. CLOUDS SHOULD LIFT AND
SCATTER BY MIDDAY.

KSEA...MVFR CIGS THIS MORNING...LIFTING ABOVE 3K FT AND SCATTERING
BY AROUND 18Z. S-SW WIND 4-8 KT BECOMING NLY FOR A FEW HOURS THIS
EVENING. A PUGET SOUND CONVERGENCE ZONE MAY REFORM AND PRODUCE
ADDITIONAL SHOWERS LATE THIS AFTERNOON AND EVENING...OTHERWISE JUST
ISOLATED SHOWER ACTIVITY.

&&

.MARINE...A WEAK DECAYING TROUGH WILL PASS NORTH OF THE AREA TONIGHT
ENHANCING ONSHORE FLOW THIS EVENING. WESTERLY WINDS MAY REACH
LOW-END SMALL CRAFT TO 25 KNOTS FOR A FEW HOURS THIS EVENING IN THE
CENTRAL/E STRAIT. ANOTHER STRONGER SURFACE TROUGH WILL BRING
INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY. SMALL CRAFT WINDS ARE
AGAIN LIKELY AT TIMES IN THE CENTRAL/E STRAIT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 310355
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
855 PM PDT SAT AUG 30 2014

.SYNOPSIS...WESTERLY FLOW ALOFT WILL MAINTAIN A UNSETTLED AND COOLER
THAN NORMAL WEATHER PATTERN OVER WESTERN WASHINGTON THROUGH
WEDNESDAY. WEAK WEATHER SYSTEMS EMBEDDED IN THE FLOW ALOFT WILL
BRING PERIODS OF LIGHT SHOWERS MAINLY SUNDAY AND TUESDAY INTO
WEDNESDAY MORNING. AN OFFSHORE UPPER LEVEL RIDGE WILL MOVE OVER THE
REGION AFTER WEDNESDAY FOR WARMER AND DRIER WEATHER INTO NEXT
WEEKEND.

&&

.SHORT TERM...WEAK SHOWERS DRIFTING OFF OF THE OLYMPICS THIS EVENING
HAVE BEEN FORMING A NARROW BAND ACROSS THE AREA FROM SEA-TAC TO
SOUTH SEATTLE. THESE SHOWERS SHOULD DIMINISH BY AROUND 06Z/11 PM AS
THE AIR MASS BECOMES MORE STABLE.

A STRONGER THAN NORMAL 110KT WESTERLY JETSTREAM WILL BE THE PRIMARY
FACTOR IN THE WEATHER PATTERN THROUGH MID WEEK. SMALL WEAK UPPER
LEVEL SHORTWAVE TROUGHS EMBEDDED IN THE WNW FLOW ALOFT WILL MOVE
PERIODICALLY ACROSS W WA. A WEAK SHORTWAVE TROUGH NEAR 135W AT 02Z/7
PM WILL MOVE ACROSS THE AREA SUNDAY MORNING. THIS WAVE IS NOT VERY
STRONG TO BEGIN WITH AND THE DARK SLOT BEHIND THE WAVE ON WATER
VAPOR IMAGERY HAS BEEN FILLING IN...INDICATING A WEAKENING TREND.
THIS WAVE SHOULD BRING A MINOR INCREASE IN SHOWER ACTIVITY SUNDAY
MORNING...BUT NOT ENOUGH TO GO WITH LIKELY POPS. VORTICITY PROGS
SUGGEST ANOTHER WEAK WAVE TRAILING THE FIRST FEATURE...WHICH SHOULD
MAINTAIN SCATTERED SHOWERS SUNDAY AFTERNOON.

THE MODELS HAVE BEEN HAVING AN UNDERSTANDABLY DIFFICULT TIME IN
RESOLVING THESE SMALL WEAK WAVES...AND ARE STILL HAVING A HARD TIME
WITH THE THIRD WAVE SUNDAY EVENING. THIS FEATURE IS THE STRONGER
LOOKING ONE ON WATER VAPOR IMAGERY OUT NEAR 155W AT 02Z. PREVIOUS
MODEL RUNS BROUGHT THE WAVE MORE DIRECTLY ACROSS THE AREA...BUT
LATEST MODELS TAKE IT OVER S B.C...JUST BRUSHING THE N PART OF W WA
SUNDAY EVENING. CURRENT POPS MAY BE A LITTLE LOW FOR SUNDAY AND MAY
BE A LITTLE HIGH SUNDAY EVENING.

THE JETSTREAM WILL SHIFT NORTH OVER S B.C. ON MONDAY AS A FLAT WEAK
SHORTWAVE RIDGE MOVES ACROSS THE AREA. MONDAY SHOULD BE GENERALLY
DRY AND SLIGHTLY WARMER WITH A BIT MORE SUNSHINE AS WELL.

THE MODELS AGREE ON BRINGING A STRONGER HIGHER AMPLITUDE SHORTWAVE
TROUGH ACROSS THE AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.
MODELS HAVE BEEN RATHER MISERLY WITH THE POPS SO IT WOULD NOT BE
SURPRISING TO SEE FUTURE GUIDANCE HIT IT A LITTLE HARDER. AT THIS
POINT THE NAM12 LOOKS IT HAS A REASONABLE SOLUTION.

WITH THE ACTIVE WEATHER PATTERN EARLY THIS WEEK...MAX TEMPERATURES
WILL REMAIN BELOW NORMAL IN THE 60S TO LOWER 70S. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 333 PM AFD...OVERALL
CONFIDENCE FOR THE BIG PICTURE IN THE EXTENDED PERIOD A BIT HIGHER
THAN OVERNIGHT. MEDIUM RANGE MODELS CONTINUE TO SHOW AN UPPER LEVEL
TROUGH MOVING INTO THE REGION TUESDAY AFTERNOON AND EVENING BRINGING
ANOTHER ROUND OF SHOWERS TO THE REGION THROUGH EARLY WEDNESDAY
MORNING. MODELS ALL SHOW THE ZONAL FLOW OVER THE NORTHEAST PACIFIC
BREAKING DOWN AT THIS POINT INTO A HIGHER AMPLITUDE PATTERN AS A
RIDGE BUILDS INTO THE GULF OF ALASKA. MODELS NOW IN BETTER AGREEMENT
ON THE DOWNSTREAM DEVELOPMENT OF DRY SPLIT FLOW OVER PACIFIC
NORTHWEST THURSDAY FOLLOWED BY THE LARGE SCALE RIDGE SHIFTING EAST
FRIDAY THROUGH THE WEEKEND WITH CONTINUED DRY AND WARMER WEATHER.

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE REGION WILL SHIFT EWD
TONIGHT WITH LIGHT NW FLOW ALOFT. LOW LEVEL ONSHORE FLOW BEHIND THE
SURFACE TROUGH WILL DOMINATE THROUGH SUNDAY. MOIST AND WEAKLY
UNSTABLE ATMOSPHERE. SCATTERED SHOWERS.

A PUGET SOUND CONVERGENCE ZONE WILL FOCUS MOST SHOWER ACTIVITY
BETWEEN TACOMA AND EVERETT. THE CONVERGENCE ZONE SHOULD
DISSIPATE LATER TONIGHT. THERE COULD BE PERIODS OF MVFR AT THE
KBFI/KSEA TERMINALS TONIGHT...WITH MVFR BECOMING MORE WIDESPREAD
LATE TONIGHT AND SUNDAY MORNING. CLOUDS SHOULD LIFT TO VFR WITH
SCATTERING BY MIDDAY SUNDAY.

KSEA...A PUGET SOUND CONVERGENCE ZONE WILL KEEP SHOWER ACTIVITY
GOING THROUGH MUCH OF TONIGHT...THEN JUST A FEW SHOWERS THROUGH
SUNDAY. CIGS MOSTLY VFR THIS EVENING...WITH MVFR CIGS DEVELOPING
LATER TONIGHT AND SUNDAY MORNING. IMPROVING CIGS AFTER 18Z.

&&

.MARINE...WESTERLY FLOW BEHIND A TROUGH WILL MAINTAIN SMALL CRAFT
WINDS IN THE CENTRAL AND EAST STRAIT THROUGH MOST OF TONIGHT. THE
FLOW WILL WEAKEN ON SUNDAY. A WEAK DECAYING SURFACE TROUGH WILL
INCREASE ONSHORE FLOW SLIGHTLY ON SUNDAY NIGHT. ANOTHER STRONGER
TROUGH WILL BRING INCREASED ONSHORE FLOW TUESDAY AND WEDNESDAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
     THROUGH 3 AM PDT SUNDAY.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML












000
FXUS66 KSEW 302235
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
333 PM PDT SAT AUG 30 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH MOVING OUT OF WESTERN WASHINGTON
THIS EVENING WILL KEEP A FEW LINGERING SHOWERS OVER THE AREA THIS
EVENING. WEAK UPPER LEVEL RIDGING WILL BUILD OVER WESTERN WASHINGTON
TONIGHT BRINGING DRIER CONDITIONS TO MUCH OF THE AREA THROUGH
SUNDAY. ANOTHER RELATIVELY WEAK FRONTAL SYSTEM WILL BEGIN TO AFFECT
THE REGION SUNDAY NIGHT INTO LABOR DAY MORNING. HIGH PRESSURE
ALOFT WILL BUILD OVER THE AREA DURING THE AFTERNOON ON LABOR DAY
FOLLOWED BY ANOTHER WEAK SYSTEM LATER TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL THAT MOVED OVER WESTERN WASHINGTON
EARLIER TODAY WILL CONTINUE TO SHIFT EAST OF THE CASCADES THIS
EVENING. SHOWERS HAVE GENERALLY TAPERED OFF THIS AFTERNOON...WITH A
FEW OF THE MORE ORGANIZED BANDS OF PRECIPITATION LINGERING SOUTH OF
THE KING COUNTY/SNOHOMISH COUNTY LINE INTO THE SOUTHWEST INTERIOR.
PRECIPITATION WILL CONTINUE TO TAPER OFF THIS EVENING AS THE UPPER
LEVEL LOW CONTINUES TO SLIDE EAST. BOTH THE NAM12 AND UW WRF RUNS DO
SHOW A WEAK PSCZ FORMING OVER THE I90 CORRIDOR THIS EVENING. THIS
MAY KEEP A FEW SHOWERS OVER THE LOWLANDS...OTHERWISE EXPECT SHOWERS
TO RETREAT TO THE CASCADES AS HIGH PRESSURE BUILDS ALOFT OVER THE
REGION TONIGHT THROUGH SUNDAY MORNING. BY EARLY SUNDAY MORNING THE
THREAT OF SHOWERS WILL BE LIMITED MAINLY TO THE CASCADES.

THE NEXT SYSTEM WILL BEGIN TO AFFECT THE AREA SUNDAY EVENING INTO
MONDAY MORNING. MODEL RUNS CONTINUE TREND TOWARDS A SLOWER...AND
MUCH WEAKER SOLUTION WITH THIS SYSTEM. BRINGING PRECIPITATION INTO
WESTERN WASHINGTON LATE SUNDAY NIGHT AND THE FRONT ONSHORE EARLY
MONDAY MORNING. NEARLY ALL THE MODELS NOW SHOWING THIS FRONT
ESSENTIALLY FALLING APART AS IT MOVES ONSHORE. HAVE TRENDED POPS AND
PRECIP BACK...CONTINUING TO HIGHLIGHT THE BEST CHANCE FOR
PRECIPITATION AFTER MIDNIGHT SUNDAY NIGHT INTO EARLY MONDAY MORNING
FOLLOWED BY DRYING DURING THE AFTERNOON AS AN UPPER RIDGE TAKES
BRIEF HOLD OF THE AREA. SOLID ONSHORE FLOW THROUGH THE PERIOD WILL
KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

.LONG TERM...OVERALL CONFIDENCE FOR THE BIG PICTURE IN THE EXTENDED
PERIOD A BIT HIGHER THAN OVERNIGHT. MEDIUM RANGE MODELS CONTINUE TO
SHOW AN UPPER LEVEL TROUGH MOVING INTO THE REGION TUESDAY AFTERNOON
AND EVENING BRINGING ANOTHER ROUND OF SHOWERS TO THE REGION THROUGH
EARLY WEDNESDAY MORNING. MODELS ALL SHOW THE ZONAL FLOW OVER THE
NORTHEAST PACIFIC BREAKING DOWN AT THIS POINT INTO A HIGHER
AMPLITUDE PATTERN AS A RIDGE BUILDS INTO THE GULF OF ALASKA. MODELS
NOW IN BETTER AGREEMENT ON THE DOWNSTREAM DEVELOPMENT OF DRY SPLIT
FLOW OVER PACIFIC NORTHWEST THURSDAY FOLLOWED BY THE LARGE SCALE
RIDGE SHIFTING EAST FRIDAY THROUGH THE WEEKEND WITH CONTINUED DRY
AND WARMER WEATHER.

&&

.AVIATION...THE CLOUDS AND AREAS OF RAIN WILL SHIFT INLAND THROUGH
THE AFTERNOON AND EVENING. A LITTLE SUNSHINE ON THE COAST OUGHT TO
WORK INLAND SOMEWHAT...AND SUNBREAKS ARE NOT A BAD BET FOR THE
INLAND PORTION OF WRN WA EARLY THIS EVENING. THE UW WRFGFS SUGGESTS
A FEW SHOWERS LINGERING AROUND SEATTLE...PERHAPS IN A WEAK PSCZ.
ONSHORE FLOW TONIGHT AND THE MARINE LAYER ARE LIKELY TO GIVE MORNING
CLOUDS ON SUNDAY...PERHAPS GIVING WAY TO PARTLY SUNNY SKIES SUNDAY
AFTERNOON AND EVENING. THE FLOW ALOFT WILL TURN FROM WSW THIS
AFTERNOON TO WNW ON SUNDAY.

KSEA...SCATTERED SHOWERS WITH THE WEAK SYSTEM MOVING THROUGH WRN WA
THIS AFTERNOON COULD LINGER INTO THE EARLY PART OF THE EVENING...BUT
WE MAY SEE SOME SUNBREAKS AS WELL. OVERNIGHT LOW CLOUDS OUGHT TO SET
UP FOR MORNING LOW CLOUDS ON SUNDAY AND THEN SOME CLEARING IN THE
AFTERNOON.

&&

.MARINE...THE WEAK LOW PRESSURE CENTER WAS OVER SW WA THIS
AFTERNOON. ONSHORE FLOW SHOULD INCREASE THIS EVENING...AND THE
WRFGFS GIVES WINDS REACHING WESTERLY SMALL CRAFT ADVISORY STRENGTH
IN THE CENTRAL/EASTERN STRAIT. THE NEXT WEATHER SYSTEM FOR SUN NIGHT
WHICH THE 12Z NAM SHOWED WELL ENOUGH IS NOT SIGNIFICANT IN THE
GLOBAL MODELS.



&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
THIS EVENING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML









000
FXUS66 KSEW 302235
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
333 PM PDT SAT AUG 30 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH MOVING OUT OF WESTERN WASHINGTON
THIS EVENING WILL KEEP A FEW LINGERING SHOWERS OVER THE AREA THIS
EVENING. WEAK UPPER LEVEL RIDGING WILL BUILD OVER WESTERN WASHINGTON
TONIGHT BRINGING DRIER CONDITIONS TO MUCH OF THE AREA THROUGH
SUNDAY. ANOTHER RELATIVELY WEAK FRONTAL SYSTEM WILL BEGIN TO AFFECT
THE REGION SUNDAY NIGHT INTO LABOR DAY MORNING. HIGH PRESSURE
ALOFT WILL BUILD OVER THE AREA DURING THE AFTERNOON ON LABOR DAY
FOLLOWED BY ANOTHER WEAK SYSTEM LATER TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL THAT MOVED OVER WESTERN WASHINGTON
EARLIER TODAY WILL CONTINUE TO SHIFT EAST OF THE CASCADES THIS
EVENING. SHOWERS HAVE GENERALLY TAPERED OFF THIS AFTERNOON...WITH A
FEW OF THE MORE ORGANIZED BANDS OF PRECIPITATION LINGERING SOUTH OF
THE KING COUNTY/SNOHOMISH COUNTY LINE INTO THE SOUTHWEST INTERIOR.
PRECIPITATION WILL CONTINUE TO TAPER OFF THIS EVENING AS THE UPPER
LEVEL LOW CONTINUES TO SLIDE EAST. BOTH THE NAM12 AND UW WRF RUNS DO
SHOW A WEAK PSCZ FORMING OVER THE I90 CORRIDOR THIS EVENING. THIS
MAY KEEP A FEW SHOWERS OVER THE LOWLANDS...OTHERWISE EXPECT SHOWERS
TO RETREAT TO THE CASCADES AS HIGH PRESSURE BUILDS ALOFT OVER THE
REGION TONIGHT THROUGH SUNDAY MORNING. BY EARLY SUNDAY MORNING THE
THREAT OF SHOWERS WILL BE LIMITED MAINLY TO THE CASCADES.

THE NEXT SYSTEM WILL BEGIN TO AFFECT THE AREA SUNDAY EVENING INTO
MONDAY MORNING. MODEL RUNS CONTINUE TREND TOWARDS A SLOWER...AND
MUCH WEAKER SOLUTION WITH THIS SYSTEM. BRINGING PRECIPITATION INTO
WESTERN WASHINGTON LATE SUNDAY NIGHT AND THE FRONT ONSHORE EARLY
MONDAY MORNING. NEARLY ALL THE MODELS NOW SHOWING THIS FRONT
ESSENTIALLY FALLING APART AS IT MOVES ONSHORE. HAVE TRENDED POPS AND
PRECIP BACK...CONTINUING TO HIGHLIGHT THE BEST CHANCE FOR
PRECIPITATION AFTER MIDNIGHT SUNDAY NIGHT INTO EARLY MONDAY MORNING
FOLLOWED BY DRYING DURING THE AFTERNOON AS AN UPPER RIDGE TAKES
BRIEF HOLD OF THE AREA. SOLID ONSHORE FLOW THROUGH THE PERIOD WILL
KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

.LONG TERM...OVERALL CONFIDENCE FOR THE BIG PICTURE IN THE EXTENDED
PERIOD A BIT HIGHER THAN OVERNIGHT. MEDIUM RANGE MODELS CONTINUE TO
SHOW AN UPPER LEVEL TROUGH MOVING INTO THE REGION TUESDAY AFTERNOON
AND EVENING BRINGING ANOTHER ROUND OF SHOWERS TO THE REGION THROUGH
EARLY WEDNESDAY MORNING. MODELS ALL SHOW THE ZONAL FLOW OVER THE
NORTHEAST PACIFIC BREAKING DOWN AT THIS POINT INTO A HIGHER
AMPLITUDE PATTERN AS A RIDGE BUILDS INTO THE GULF OF ALASKA. MODELS
NOW IN BETTER AGREEMENT ON THE DOWNSTREAM DEVELOPMENT OF DRY SPLIT
FLOW OVER PACIFIC NORTHWEST THURSDAY FOLLOWED BY THE LARGE SCALE
RIDGE SHIFTING EAST FRIDAY THROUGH THE WEEKEND WITH CONTINUED DRY
AND WARMER WEATHER.

&&

.AVIATION...THE CLOUDS AND AREAS OF RAIN WILL SHIFT INLAND THROUGH
THE AFTERNOON AND EVENING. A LITTLE SUNSHINE ON THE COAST OUGHT TO
WORK INLAND SOMEWHAT...AND SUNBREAKS ARE NOT A BAD BET FOR THE
INLAND PORTION OF WRN WA EARLY THIS EVENING. THE UW WRFGFS SUGGESTS
A FEW SHOWERS LINGERING AROUND SEATTLE...PERHAPS IN A WEAK PSCZ.
ONSHORE FLOW TONIGHT AND THE MARINE LAYER ARE LIKELY TO GIVE MORNING
CLOUDS ON SUNDAY...PERHAPS GIVING WAY TO PARTLY SUNNY SKIES SUNDAY
AFTERNOON AND EVENING. THE FLOW ALOFT WILL TURN FROM WSW THIS
AFTERNOON TO WNW ON SUNDAY.

KSEA...SCATTERED SHOWERS WITH THE WEAK SYSTEM MOVING THROUGH WRN WA
THIS AFTERNOON COULD LINGER INTO THE EARLY PART OF THE EVENING...BUT
WE MAY SEE SOME SUNBREAKS AS WELL. OVERNIGHT LOW CLOUDS OUGHT TO SET
UP FOR MORNING LOW CLOUDS ON SUNDAY AND THEN SOME CLEARING IN THE
AFTERNOON.

&&

.MARINE...THE WEAK LOW PRESSURE CENTER WAS OVER SW WA THIS
AFTERNOON. ONSHORE FLOW SHOULD INCREASE THIS EVENING...AND THE
WRFGFS GIVES WINDS REACHING WESTERLY SMALL CRAFT ADVISORY STRENGTH
IN THE CENTRAL/EASTERN STRAIT. THE NEXT WEATHER SYSTEM FOR SUN NIGHT
WHICH THE 12Z NAM SHOWED WELL ENOUGH IS NOT SIGNIFICANT IN THE
GLOBAL MODELS.



&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
THIS EVENING.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML










000
FXUS66 KSEW 301618
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 AM PDT SAT AUG 30 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH MOVING THROUGH THE PACIFIC
NORTHWEST TODAY WILL KEEP SHOWERS OVER THE AREA TODAY. WEAK UPPER
LEVEL RIDGING WILL BUILD OVER WESTERN WASHINGTON TONIGHT AS THE
UPPER LEVEL TROUGH SHIFTS EAST BRINGING DRIER CONDITIONS TO MUCH OF
THE AREA. ANOTHER RELATIVELY WEAK FRONTAL SYSTEM WILL BEGIN TO
AFFECT THE REGION SUNDAY AFTERNOON AND EVENING. HIGH PRESSURE ALOFT
WILL BUILD OVER THE AREA LABOR DAY FOLLOWED BY ANOTHER WEAK SYSTEM
LATER TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL TROUGH MOVING OVER WESTERN WASHINGTON
AND OREGON THIS MORNING AND 70 KT JET NOSING INTO CENTRAL OREGON
SUPPORTING WET CONDITIONS FROM CENTRAL OREGON NORTH INTO
SOUTHWESTERN WASHINGTON THIS MORNING. A MORE ORGANIZED BAND OF
PRECIPITATION EXTENDING FROM GRAYS HARBOR INTO THE SOUTHERN SOUND
HAS PRODUCED MODERATE RAIN AT SEVERAL LOCATIONS. EXPECT THIS BAND TO
FILL SHIFT NORTH AND EAST OVER THE NEXT FEW HOURS BRINGING RAIN AND
OR SHOWERS INTO THE METRO AREA THROUGH THE EARLY AFTERNOON. EXPECT
THE HEAVIEST PRECIPITATION TO FALL FROM SEATTLE SOUTHWARD.

PRECIPITATION WILL TAPER OFF LATE IN THE AFTERNOON AND OVERNIGHT AS
HIGH PRESSURE ALOFT BUILDS OVER THE REGION TONIGHT THROUGH SUNDAY
MORNING. BY LATE TONIGHT THE THREAT OF SHOWERS WILL BE LIMITED
MAINLY TO THE CASCADES...WITH LINGERING LIGHT SHOWERS OVER THE COAST
AND MOUNTAINS BY SUNDAY MORNING.

THE NEXT SYSTEM WILL BEGIN TO AFFECT THE AREA LATE SUNDAY AFTERNOON
AND EVENING. OVERNIGHT RUNS OF THE MODELS STRUGGLED SOMEWHAT WITH
THE TRACK...TIMING...AND STRENGTH OF THIS SYSTEM. MOST GUIDANCE
AGREES ON THE BULK OF THE PRECIPITATION FALLING SUNDAY NIGHT WHILE
SOME MODELS REMAIN SLOWER AND WEAKER...DELAYING ANY PRECIPITATION
UNTIL MONDAY MORNING. THE CURRENT FORECAST CONTINUES TO HIGHLIGHT
THE BEST CHANCE OF PRECIPITATION OVER THE NORTHWEST HALF OF THE CWA
SUNDAY NIGHT.  AN UPPER RIDGE WILL BUILD INTO THE PACIFIC NORTHWEST
ON LABOR DAY WITH DRIER CONDITIONS. SOLID ONSHORE FLOW THROUGH THE
PERIOD WILL KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

.LONG TERM...CONFIDENCE THROUGH THE EXTENDED PERIOD REMAINS LOW.
MEDIUM RANGE MODELS CONTINUE TO SHOW AN UPPER LEVEL TROUGH MOVING
INTO THE REGION TUESDAY NIGHT AND OR WEDNESDAY MORNING. THERE REMAIN
DIFFERENCES ON THE SPECIFIC TIMING...PLACEMENT...AND STRENGTH OF
RAINFALL. MODELS ALL SHOW THE ZONAL FLOW OVER THE NORTHEAST PACIFIC
BREAKING DOWN AT THIS POINT INTO A HIGHER AMPLITUDE PATTERN AS A
RIDGE BUILDS INTO THE GULF OF ALASKA. MODELS STILL DISAGREE ON
DOWNSTREAM CONDITIONS OVER THE PACIFIC NORTHWEST THURSDAY...SOME
SHOWING LINGERING UNSETTLED WEATHER...WHILE OTHERS SHOWING A QUICKER
TRANSITION TO DRIER CONDITIONS. MOVING INTO THE WEEKEND...THERE
CURRENTLY IS SOME CONSENSUS ON THE LARGE SCALE RIDGE SHIFTING EAST
FRIDAY THROUGH THE WEEKEND WITH DRIER AND WARMER WEATHER.

&&

.AVIATION...CLOUDY WITH AREAS OF PCPN TODAY AND THE MTNS WILL BE
MOSTLY OBSCURED. AN UPPER TROUGH OVER THE PACNW WILL SHIFT EAST TO
THE ROCKIES SUN. THE AIR IS MOIST WITH WSW FLOW ALOFT BECOMING WNW
SUN. A WEATHER SYSTEM AND 1012 MB LOW JUST OFF THE SOUTH WA COAST
THIS MORNING WILL MOVE EAST THROUGH MAINLY THE SRN PTN OF WRN WA
TODAY. AT 830AM THERE IS A BAND OF RAIN IN AN ARC FROM AROUND HQM TO
OLM AND EAST INTO THE CASCADES AND ALSO AREAS OF PCPN SOUTH INTO NW
ORE.

KSEA...A BAND OF RAIN WILL MOVE THROUGH THE SEATTLE AREA THROUGH
MIDDAY AND THEN BECOME SCATTERED SHOWERS IN THE AFTERNOON. THIS IS
ASSOCIATED WITH A WEAK LOW PRESSURE SYSTEM MOVING INTO SW WA
TODAY.

&&

.MARINE...A 1012 MB LOW WILL MOVE ASHORE NEAR THE SOUTH WA COAST
THIS MORNING. LIGHT ONSHORE FLOW WILL CONTINUE TONIGHT AND SUNDAY.
ANOTHER WEATHER SYSTEM WILL EACH THE AREA SUN NIGHT...THE 12Z NAM
SHOWS THIS FRONT WEAKENING AFTER IT CROSSES 130W SUNDAY AFTERNOON
AND BREAKING UP OVER WRN WA MONDAY MORNING.


&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 301618
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 AM PDT SAT AUG 30 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH MOVING THROUGH THE PACIFIC
NORTHWEST TODAY WILL KEEP SHOWERS OVER THE AREA TODAY. WEAK UPPER
LEVEL RIDGING WILL BUILD OVER WESTERN WASHINGTON TONIGHT AS THE
UPPER LEVEL TROUGH SHIFTS EAST BRINGING DRIER CONDITIONS TO MUCH OF
THE AREA. ANOTHER RELATIVELY WEAK FRONTAL SYSTEM WILL BEGIN TO
AFFECT THE REGION SUNDAY AFTERNOON AND EVENING. HIGH PRESSURE ALOFT
WILL BUILD OVER THE AREA LABOR DAY FOLLOWED BY ANOTHER WEAK SYSTEM
LATER TUESDAY.

&&

.SHORT TERM...THE UPPER LEVEL TROUGH MOVING OVER WESTERN WASHINGTON
AND OREGON THIS MORNING AND 70 KT JET NOSING INTO CENTRAL OREGON
SUPPORTING WET CONDITIONS FROM CENTRAL OREGON NORTH INTO
SOUTHWESTERN WASHINGTON THIS MORNING. A MORE ORGANIZED BAND OF
PRECIPITATION EXTENDING FROM GRAYS HARBOR INTO THE SOUTHERN SOUND
HAS PRODUCED MODERATE RAIN AT SEVERAL LOCATIONS. EXPECT THIS BAND TO
FILL SHIFT NORTH AND EAST OVER THE NEXT FEW HOURS BRINGING RAIN AND
OR SHOWERS INTO THE METRO AREA THROUGH THE EARLY AFTERNOON. EXPECT
THE HEAVIEST PRECIPITATION TO FALL FROM SEATTLE SOUTHWARD.

PRECIPITATION WILL TAPER OFF LATE IN THE AFTERNOON AND OVERNIGHT AS
HIGH PRESSURE ALOFT BUILDS OVER THE REGION TONIGHT THROUGH SUNDAY
MORNING. BY LATE TONIGHT THE THREAT OF SHOWERS WILL BE LIMITED
MAINLY TO THE CASCADES...WITH LINGERING LIGHT SHOWERS OVER THE COAST
AND MOUNTAINS BY SUNDAY MORNING.

THE NEXT SYSTEM WILL BEGIN TO AFFECT THE AREA LATE SUNDAY AFTERNOON
AND EVENING. OVERNIGHT RUNS OF THE MODELS STRUGGLED SOMEWHAT WITH
THE TRACK...TIMING...AND STRENGTH OF THIS SYSTEM. MOST GUIDANCE
AGREES ON THE BULK OF THE PRECIPITATION FALLING SUNDAY NIGHT WHILE
SOME MODELS REMAIN SLOWER AND WEAKER...DELAYING ANY PRECIPITATION
UNTIL MONDAY MORNING. THE CURRENT FORECAST CONTINUES TO HIGHLIGHT
THE BEST CHANCE OF PRECIPITATION OVER THE NORTHWEST HALF OF THE CWA
SUNDAY NIGHT.  AN UPPER RIDGE WILL BUILD INTO THE PACIFIC NORTHWEST
ON LABOR DAY WITH DRIER CONDITIONS. SOLID ONSHORE FLOW THROUGH THE
PERIOD WILL KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

.LONG TERM...CONFIDENCE THROUGH THE EXTENDED PERIOD REMAINS LOW.
MEDIUM RANGE MODELS CONTINUE TO SHOW AN UPPER LEVEL TROUGH MOVING
INTO THE REGION TUESDAY NIGHT AND OR WEDNESDAY MORNING. THERE REMAIN
DIFFERENCES ON THE SPECIFIC TIMING...PLACEMENT...AND STRENGTH OF
RAINFALL. MODELS ALL SHOW THE ZONAL FLOW OVER THE NORTHEAST PACIFIC
BREAKING DOWN AT THIS POINT INTO A HIGHER AMPLITUDE PATTERN AS A
RIDGE BUILDS INTO THE GULF OF ALASKA. MODELS STILL DISAGREE ON
DOWNSTREAM CONDITIONS OVER THE PACIFIC NORTHWEST THURSDAY...SOME
SHOWING LINGERING UNSETTLED WEATHER...WHILE OTHERS SHOWING A QUICKER
TRANSITION TO DRIER CONDITIONS. MOVING INTO THE WEEKEND...THERE
CURRENTLY IS SOME CONSENSUS ON THE LARGE SCALE RIDGE SHIFTING EAST
FRIDAY THROUGH THE WEEKEND WITH DRIER AND WARMER WEATHER.

&&

.AVIATION...CLOUDY WITH AREAS OF PCPN TODAY AND THE MTNS WILL BE
MOSTLY OBSCURED. AN UPPER TROUGH OVER THE PACNW WILL SHIFT EAST TO
THE ROCKIES SUN. THE AIR IS MOIST WITH WSW FLOW ALOFT BECOMING WNW
SUN. A WEATHER SYSTEM AND 1012 MB LOW JUST OFF THE SOUTH WA COAST
THIS MORNING WILL MOVE EAST THROUGH MAINLY THE SRN PTN OF WRN WA
TODAY. AT 830AM THERE IS A BAND OF RAIN IN AN ARC FROM AROUND HQM TO
OLM AND EAST INTO THE CASCADES AND ALSO AREAS OF PCPN SOUTH INTO NW
ORE.

KSEA...A BAND OF RAIN WILL MOVE THROUGH THE SEATTLE AREA THROUGH
MIDDAY AND THEN BECOME SCATTERED SHOWERS IN THE AFTERNOON. THIS IS
ASSOCIATED WITH A WEAK LOW PRESSURE SYSTEM MOVING INTO SW WA
TODAY.

&&

.MARINE...A 1012 MB LOW WILL MOVE ASHORE NEAR THE SOUTH WA COAST
THIS MORNING. LIGHT ONSHORE FLOW WILL CONTINUE TONIGHT AND SUNDAY.
ANOTHER WEATHER SYSTEM WILL EACH THE AREA SUN NIGHT...THE 12Z NAM
SHOWS THIS FRONT WEAKENING AFTER IT CROSSES 130W SUNDAY AFTERNOON
AND BREAKING UP OVER WRN WA MONDAY MORNING.


&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML







000
FXUS66 KSEW 301026
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
326 AM PDT SAT AUG 30 2014

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA TODAY
FOR SCATTERED TO NUMEROUS SHOWERS. EXPECT WEAK HIGH PRESSURE ALOFT
TO MOVE OVER THE REGION TONIGHT FOR MORE SETTLED CONDITIONS.
ANOTHER LOW PRESSURE SYSTEM WILL IMPACT THE REGION ON SUNDAY. LOOK
FOR HIGH PRESSURE ALOFT TO PREVAIL ON LABOR DAY.

&&

.SHORT TERM...
AN UPPER TROF AND ASSOCIATED SURFACE TROF WILL MOVE ACROSS THE
REGION TODAY FOR UNSETTLED CONDITIONS. IT LOOKS LIKE THE HEAVIEST
PRECIP WILL FALL ACROSS THE CENTRAL PART OF THE CWA...THUS THE
POPS AND QPF WERE ADJUSTED UPWARD OVER THIS AREA.

HIGH PRESSURE ALOFT WILL PREVAIL OVER THE REGION TONIGHT THROUGH
SUNDAY MORNING FOR MORE SETTLED CONDITIONS. BY LATE TONIGHT...THE
THREAT OF SHOWERS /ALBEIT LOW/ WILL BECOME CONFINED TO MAINLY THE
CASCADES. THERE WILL PROBABLY BE SOME STRAY LIGHT SHOWERS OVER THE
CWA SUNDAY MORNING BUT KEPT POPS LOW AND CONFINED THE MENTION TO
MAINLY THE COAST AND MOUNTAINS.

THERE CONTINUED TO BE DIFFERENCES BETWEEN THE MODELS CONCERNING
THE SUNDAY SYSTEM. THE NAM AND CANADIAN MODELS HAVE BEEN
CONSISTENT WITH THE TRACK...TIMING...AND STRENGTH OF THIS SYSTEM.
BOTH MODELS INDICATED THAT THE BEST CHANCE OF PRECIP WILL BE
ACROSS THE NORTHWEST HALF OF THE CWA DURING THE SUNDAY NIGHT
TIME FRAME. IN CONTRAST...THE GFS WAS SLOWER AND MUCH WEAKER WITH
THIS SYSTEM. THE LATEST ECMWF APPEARED TO BE A COMPROMISE BETWEEN
THESE TWO SOLUTIONS...WHICH THE FORECAST ESSENTIALLY REFLECTED.
HAVE PLACED THE HIGHEST POPS ACROSS THE NORTHWEST PART OF THE
CWA...WHICH WAS WHAT THE ECMWF INDICATED.

AN UPPER RIDGE WILL PREVAIL OVER THE PACIFIC NORTHWEST ON LABOR
DAY FOR IMPROVED CONDITIONS. THE SURFACE FLOW WILL BE STRONG
ONSHORE...SO TEMPS ACROSS THE LOWLANDS SHOULD BE NEAR OR SLIGHTLY
BELOW NORMAL.

.LONG TERM...
CONFIDENCE IN THIS PERIOD WAS NOT VERY HIGH. THE MEDIUM RANGE
SOLUTIONS AGREED THAT AN UPPER TROF WILL MOVE OVER THE REGION ON
TUE BUT THERE WAS SOME DISAGREEMENT IN THE DETAILS...NAMELY TIMING
AND STRENGTH.

BEYOND TUE...THE DIFFERENCES IN THE MEDIUM RANGE SOLUTIONS BECOME
GREATER...WITH SOME SOLUTIONS KEEPING AN UPPER TROF OVER THE AREA
THROUGH THU WHILE OTHERS HAD AN UPPER RIDGE OVER THE REGION. THE
OPERATIONAL MODELS GENERALLY AGREED THAT THE CWA WILL BE UNDER THE
INFLUENCE OF AN UPPER RIDGE ON FRI BUT THEY DIFFERED ON THE
STRENGTH OF THIS RIDGE.

THE MAIN CHANGES IN THE EXTENDED PERIOD WERE TO BLEND BETTER WITH
ADJACENT WEATHER FORECAST OFFICES.

&&

.AVIATION...A BROAD UPPER TROUGH AXIS WILL CROSS WRN WA TODAY THEN
MOVE OVER ERN WA BY TONIGHT. LARGE-SCALE LIFT WITHIN A MOIST AIR
MASS WILL SUPPORT SHOWERS AT TIMES FOR THE NEXT 18 HOURS. SHOWERS
ALONG THE COAST NOW WILL GRADUALLY SPREAD ACROSS WRN WA THIS
MORNING. AS A RESULT...CIGS WILL BECOME LOWER THROUGH
MID-MORNING...WITH HEAVIER SHOWERS LOWERING CIGS BELOW 020 AND
REDUCING VSBYS INTO 4-6SM RANGE.  SHOWERS SHOULD DECREASE TONIGHT.

KSEA...CIGS WILL LOWER THIS MORNING INTO 025-050 RANGE. SHOWER
ACTIVITY WILL PICK UP IN THE 12Z-16Z TIME FRAME...WITH HEAVIER
SHOWERS BRINGING CIGS INTO 010-020 RANGE WITH SHOWERS REDUCING VSBYS
TO 4-6SM AT TIMES. SCATTERED SHOWERS TO REMAIN NEAR TERMINAL THROUGH
6Z.

&&

.MARINE...WEAK ONSHORE FLOW WILL CONTINUE TODAY. A WARM FRONT WILL
CROSS THE WATERS ON SUNDAY...BRINGING AN INCREASE IN SOUTHERLY
WINDS. A COLD FRONT WILL MOVE INLAND ON SUN NIGHT...WITH INCREASING
ONSHORE FLOW IN ITS WAKE. SMALL CRAFT ADVISORY WIND ARE POSSIBLE
THROUGH THE STRAIT SUNDAY NIGHT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 301026
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
326 AM PDT SAT AUG 30 2014

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA TODAY
FOR SCATTERED TO NUMEROUS SHOWERS. EXPECT WEAK HIGH PRESSURE ALOFT
TO MOVE OVER THE REGION TONIGHT FOR MORE SETTLED CONDITIONS.
ANOTHER LOW PRESSURE SYSTEM WILL IMPACT THE REGION ON SUNDAY. LOOK
FOR HIGH PRESSURE ALOFT TO PREVAIL ON LABOR DAY.

&&

.SHORT TERM...
AN UPPER TROF AND ASSOCIATED SURFACE TROF WILL MOVE ACROSS THE
REGION TODAY FOR UNSETTLED CONDITIONS. IT LOOKS LIKE THE HEAVIEST
PRECIP WILL FALL ACROSS THE CENTRAL PART OF THE CWA...THUS THE
POPS AND QPF WERE ADJUSTED UPWARD OVER THIS AREA.

HIGH PRESSURE ALOFT WILL PREVAIL OVER THE REGION TONIGHT THROUGH
SUNDAY MORNING FOR MORE SETTLED CONDITIONS. BY LATE TONIGHT...THE
THREAT OF SHOWERS /ALBEIT LOW/ WILL BECOME CONFINED TO MAINLY THE
CASCADES. THERE WILL PROBABLY BE SOME STRAY LIGHT SHOWERS OVER THE
CWA SUNDAY MORNING BUT KEPT POPS LOW AND CONFINED THE MENTION TO
MAINLY THE COAST AND MOUNTAINS.

THERE CONTINUED TO BE DIFFERENCES BETWEEN THE MODELS CONCERNING
THE SUNDAY SYSTEM. THE NAM AND CANADIAN MODELS HAVE BEEN
CONSISTENT WITH THE TRACK...TIMING...AND STRENGTH OF THIS SYSTEM.
BOTH MODELS INDICATED THAT THE BEST CHANCE OF PRECIP WILL BE
ACROSS THE NORTHWEST HALF OF THE CWA DURING THE SUNDAY NIGHT
TIME FRAME. IN CONTRAST...THE GFS WAS SLOWER AND MUCH WEAKER WITH
THIS SYSTEM. THE LATEST ECMWF APPEARED TO BE A COMPROMISE BETWEEN
THESE TWO SOLUTIONS...WHICH THE FORECAST ESSENTIALLY REFLECTED.
HAVE PLACED THE HIGHEST POPS ACROSS THE NORTHWEST PART OF THE
CWA...WHICH WAS WHAT THE ECMWF INDICATED.

AN UPPER RIDGE WILL PREVAIL OVER THE PACIFIC NORTHWEST ON LABOR
DAY FOR IMPROVED CONDITIONS. THE SURFACE FLOW WILL BE STRONG
ONSHORE...SO TEMPS ACROSS THE LOWLANDS SHOULD BE NEAR OR SLIGHTLY
BELOW NORMAL.

.LONG TERM...
CONFIDENCE IN THIS PERIOD WAS NOT VERY HIGH. THE MEDIUM RANGE
SOLUTIONS AGREED THAT AN UPPER TROF WILL MOVE OVER THE REGION ON
TUE BUT THERE WAS SOME DISAGREEMENT IN THE DETAILS...NAMELY TIMING
AND STRENGTH.

BEYOND TUE...THE DIFFERENCES IN THE MEDIUM RANGE SOLUTIONS BECOME
GREATER...WITH SOME SOLUTIONS KEEPING AN UPPER TROF OVER THE AREA
THROUGH THU WHILE OTHERS HAD AN UPPER RIDGE OVER THE REGION. THE
OPERATIONAL MODELS GENERALLY AGREED THAT THE CWA WILL BE UNDER THE
INFLUENCE OF AN UPPER RIDGE ON FRI BUT THEY DIFFERED ON THE
STRENGTH OF THIS RIDGE.

THE MAIN CHANGES IN THE EXTENDED PERIOD WERE TO BLEND BETTER WITH
ADJACENT WEATHER FORECAST OFFICES.

&&

.AVIATION...A BROAD UPPER TROUGH AXIS WILL CROSS WRN WA TODAY THEN
MOVE OVER ERN WA BY TONIGHT. LARGE-SCALE LIFT WITHIN A MOIST AIR
MASS WILL SUPPORT SHOWERS AT TIMES FOR THE NEXT 18 HOURS. SHOWERS
ALONG THE COAST NOW WILL GRADUALLY SPREAD ACROSS WRN WA THIS
MORNING. AS A RESULT...CIGS WILL BECOME LOWER THROUGH
MID-MORNING...WITH HEAVIER SHOWERS LOWERING CIGS BELOW 020 AND
REDUCING VSBYS INTO 4-6SM RANGE.  SHOWERS SHOULD DECREASE TONIGHT.

KSEA...CIGS WILL LOWER THIS MORNING INTO 025-050 RANGE. SHOWER
ACTIVITY WILL PICK UP IN THE 12Z-16Z TIME FRAME...WITH HEAVIER
SHOWERS BRINGING CIGS INTO 010-020 RANGE WITH SHOWERS REDUCING VSBYS
TO 4-6SM AT TIMES. SCATTERED SHOWERS TO REMAIN NEAR TERMINAL THROUGH
6Z.

&&

.MARINE...WEAK ONSHORE FLOW WILL CONTINUE TODAY. A WARM FRONT WILL
CROSS THE WATERS ON SUNDAY...BRINGING AN INCREASE IN SOUTHERLY
WINDS. A COLD FRONT WILL MOVE INLAND ON SUN NIGHT...WITH INCREASING
ONSHORE FLOW IN ITS WAKE. SMALL CRAFT ADVISORY WIND ARE POSSIBLE
THROUGH THE STRAIT SUNDAY NIGHT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






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