Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 021045
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST MON MAR 2 2015

.SYNOPSIS...THE WEAK WEATHER SYSTEM OVER WASHINGTON WILL MOVE SOUTH
OF THE AREA THIS MORNING. SKIES SHOULD BE MOSTLY SUNNY THIS
AFTERNOON WITH A BREEZY NORTH WIND. GENERALLY DRY WEATHER WILL
PREVAIL THE REMAINDER OF THE WEEK AND INTO THE WEEKEND...UNDER THE
INFLUENCE OF AN UPPER RIDGE AND LOW LEVEL OFFSHORE FLOW.

&&

.SHORT TERM...A WEAK UPPER SHORTWAVE HAS BEEN DIGGING SOUTHEAST
ACROSS WASHINGTON OVERNIGHT. WHILE MUCH OF THE PUGET SOUND REGION
REMAINED DRY OR NEARLY DRY...THIS FEATURE BROUGHT LIGHT
PRECIPITATION TO THE REST OF WESTERN WASHINGTON. AT 2 AM SKIES WERE
STILL MAINLY CLOUDY...BUT PRECIPITATION WAS SPOTTY AND LIGHT. THE
AIR MASS IS RATHER COOL WITH TEMPERATURES IN THE MID 30S TO MID 40S
AND THE SNOW LEVEL AROUND 1500 FT.

NORTHERLY FLOW ALOFT WILL CONTINUE TODAY AHEAD OF THE UPPER RIDGE
OFFSHORE ALONG 140W. THE SHORTWAVE WILL MOVE SOUTH OF THE FORECAST
AREA THIS MORNING...WITH THE AIR MASS DRYING FROM NORTH TO SOUTH.
SKIES SHOULD BE MOSTLY SUNNY BY LATE TODAY. THE NORTHEAST SURFACE
PRESSURE GRADIENT HAS BEEN INCREASING OVERNIGHT...AND THIS WILL
CONTINUE TODAY AS SURFACE HIGH PRESSURE MOVES SOUTH IN WESTERN
CANADA. MUCH OF THE FORECAST AREA WILL HAVE BREEZY NORTH OR
NORTHEAST WINDS...WHICH WILL BE STRONGEST IN THE NORTH INTERIOR OF
WESTERN WASHINGTON NEAR THE MOUTH OF THE FRASER RIVER.

DRY NORTHERLY FLOW ALOFT WILL CONTINUE TONIGHT THROUGH WEDNESDAY...
AS THE OFFSHORE UPPER RIDGE MOVES SLOWLY TOWARD THE PACIFIC
NORTHWEST. CLEAR SKIES AND EASING NORTHEAST SURFACE WINDS WILL MEAN
OVERNIGHT LOWS IN THE UPPER 20S TO 30S BOTH TONIGHT AND TUESDAY
NIGHT. THERE WILL BE PATCHY FOG OR FREEZING FOG DURING THE EARLY
MORNING HOURS IN THE SOUTH PUGET SOUND REGION AND SOUTH INTERIOR.
TUESDAY AND WEDNESDAY WILL BE MOSTLY SUNNY WITH HIGHS MAINLY 45 TO
55.   MCDONNAL

.LONG TERM...THE UPPER RIDGE WILL MOVE INLAND WEDNESDAY NIGHT AND
THURSDAY...WITH AN UPPER RIDGE BUILDING OVER THE REGION FRIDAY AND
DURING THE WEEKEND. A WEAK SYSTEM MOVING OVER THE NORTH SIDE OF THE
RIDGE COULD BRUSH WESTERN WASHINGTON ON THURSDAY OR THURSDAY NIGHT.
SOME MODEL RUNS KEEP THE FORECAST AREA ENTIRELY DRY...AND IF ANY
PRECIPITATION FALLS IT WILL BE LIGHT AND MOST LIKELY LIMITED TO THE
NORTH COAST AND NORTH CASCADES.

THE MODELS ARE IN RATHER POOR AGREEMENT FOR THE ENTIRE PERIOD
THURSDAY THROUGH SUNDAY...AND THE RUN TO RUN CONSISTENCY OF
INDIVIDUAL MODELS HAS NOT BEEN VERY GOOD EITHER. FOR NOW SUFFICE IT
TO SAY THAT AN UPPER RIDGE WILL PROBABLY BUILD OVER THE REGION
FRIDAY AND DURING THE WEEKEND FOR MORE DRY WEATHER.   MCDONNAL

&&

.HYDROLOGY...FLOODING IS UNLIKELY FOR THE NEXT 7 DAYS.

&&

.AVIATION...LIGHT PRECIP WILL CONTINUE IN THE INTERIOR OF WESTERN WA
EARLY THIS MORNING FROM A WEAK COLD FRONT. THE FLOW ALOFT IS
NORTHERLY. LOW LEVEL CLOUDS WILL CLEAR FROM NORTH TO SOUTH THIS
AFTERNOON AS OFFSHORE FLOW DEVELOPS. THE EXCEPTION WILL BE KCLM
WHERE NE UPSLOPE WINDS WILL KEEP CIGS NEAR 2000 FT. 33

KSEA...NORTH WINDS AT THE SURFACE. CIGS ARE MAINLY VFR THIS MORNING.
LOW LEVEL CLOUDS WILL SCATTER OUT THIS AFTERNOON WITH CLEAR SKIES
THIS EVENING. 33

&&

.MARINE...HIGH PRESSURE WILL BUILD OVER INTERIOR B.C. TODAY WITH
N/NE WINDS ACROSS WESTERN WA. SMALL CRAFT ADVISORIES ARE IN EFFECT
FOR ALL MARINE ZONES. GALES ARE POSSIBLE TONIGHT OVER THE NORTHERN
INLAND WATERS WITH FRASER RIVER OUTFLOW. OFFSHORE WINDS WILL EASE
TUESDAY AFTERNOON. WEAK HIGH PRES WILL REMAIN OVER THE REGION
WEDNESDAY AND THURSDAY FOR GENERALLY LIGHT WINDS OVER THE WATERS. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
     GALE WATCH NORTHERN INLAND WATERS TONIGHT.

&&

$$

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





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