Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 011113
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST SUN MAR 1 2015

.SYNOPSIS...AN UPPER RIDGE AND OFFSHORE LOW LEVEL FLOW WILL BRING
ANOTHER DAY OF FAIR WEATHER TO WESTERN WASHINGTON TODAY. A WEAK
WEATHER SYSTEM WILL MOVE SOUTHEAST THROUGH THE AREA TONIGHT
FOR AREAS OF LIGHT PRECIPITATION. DRY WEATHER WILL PREVAIL
THE REMAINDER OF NEXT WEEK UNDER THE INFLUENCE OF AN UPPER
RIDGE AND LOW LEVEL OFFSHORE FLOW.

&&

.SHORT TERM...NORTHERLY FLOW ALOFT CONTINUES OVER THE PACIFIC
NORTHWEST EARLY THIS MORNING...AHEAD OF A STRONG UPPER RIDGE
OFFSHORE ALONG 140W. A WEAK SYSTEM IN THE NORTHERLY FLOW HAS BROUGHT
SOME HIGH CLOUDS TO WESTERN WASHINGTON OVERNIGHT. THE TEMPERATURES
AT 2 AM RANGED FROM THE UPPER 20S AND LOWER 30S IN THE VALLEYS OF
THE SOUTH PUGET SOUND REGION AND SOUTH INTERIOR TO 40 DEGREES IN
SEATTLE.

THE UPPER FLOW WILL BACK TO NORTHWEST TODAY AS A WEAK UPPER
SHORTWAVE MOVES SOUTHEAST ALONG THE COAST OF BRITISH COLUMBIA. IT
WILL BE ANOTHER DRY DAY FOR THE FORECAST AREA. SKIES SHOULD REMAIN
MOSTLY SUNNY FOR MUCH OF THE AREA WITH ONLY SOME HIGH CLOUDS...BUT
THE COAST WILL PROBABLY HAVE MOSTLY CLOUDY SKIES THIS AFTERNOON.

THE SHORTWAVE WILL DIG ACROSS WESTERN WASHINGTON TONIGHT. IT WILL
PRODUCE A LITTLE PRECIPITATION AT THE COAST...WITH A CHANCE OF
PRECIPITATION INLAND MAINLY AFTER MIDNIGHT. PRECIPITATION AMOUNTS
WILL BE LIGHT. EVEN THE COAST AND OLYMPIC MOUNTAINS WILL GET ONLY UP
TO 0.25 INCH...WITH JUST A FEW HUNDREDTHS IN THE INTERIOR AND SOME
AREAS REMAINING DRY. THE SNOW LEVEL WILL BE AROUND 2500 FT.

AFTER SOME SPOTTY LIGHT SHOWERS MONDAY MORNING...DRY NORTHERLY FLOW
WILL DEVELOP OVER THE REGION ONCE AGAIN AND CONTINUE THROUGH
TUESDAY. A SURFACE HIGH WILL MOVE SOUTH THROUGH SOUTHWEST CANADA
TOO...PRODUCING NORTHERLY OFFSHORE FLOW LATE MONDAY AND MONDAY
NIGHT. THE NORTH INTERIOR OF WESTERN WASHINGTON WILL HAVE WINDY
CONDITIONS DUE TO ITS PROXIMITY TO THE MOUTH OF THE FRASER RIVER.
MCDONNAL

.LONG TERM...NORTHERLY FLOW ALOFT AND DRY WEATHER WILL CONTINUE
WEDNESDAY...AS THE UPPER RIDGE WEAKENS AND MOVES TO THE PACIFIC
NORTHWEST COAST. THE RIDGE WILL MOVE INLAND WEDNESDAY NIGHT AND
THURSDAY...WITH WEST OR NORTHWEST FLOW ALOFT OVER WESTERN WASHINGTON
IN ITS WAKE.

A WEAK UPPER SHORTWAVE COULD BRING SOME LIGHT PRECIPITATION TO PARTS
OF THE FORECAST AREA THURSDAY AND THURSDAY NIGHT...AND THE MOST
RECENT RUNS OF THE GFS AND CANADIAN MODELS SHOW THIS. HOWEVER
THE ECMWF AND EARLIER RUNS OF THE OTHER MODELS INDICATED DRY
WEATHER. I WILL STAND PAT WITH THE DRY FORECAST FOR NOW...AND
HOPEFULLY THE MODEL RUNS TODAY WILL HELP US PIN THIS DOWN.

ANOTHER UPPER RIDGE WILL BUILD OFFSHORE FRIDAY AND SATURDAY FOR MORE
DRY WEATHER.   MCDONNAL

&&

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

&&

.AVIATION...DRY NORTHERLY FLOW WILL PREVAIL TODAY. VFR CONDITIONS
EXPECTED WITH JUST SCT-BKN HIGH CLOUDS. A COLD FRONT WILL TRACK
SOUTH THROUGH WESTERN WA TONIGHT FOR INCREASING CLOUDS AND LIGHT
RAIN MAINLY ALONG THE COAST. MVFR CIGS ARE LIKELY OVERNIGHT WITH
SKIES CLEARING MONDAY AFTERNOON. 33

KSEA...VFR CONDITIONS TODAY. LIGHT SOUTHERLY WINDS AT THE SURFACE. 33

&&

.MARINE...WEAK LOW PRES WILL CROSS THE REGION TODAY FOR MAINLY LIGHT
WINDS. A COLD FRONT WILL MOVE SOUTH THROUGH THE WATERS TONIGHT WITH
BRIEF NW WINDS OF 15 TO 25 KT OVER THE COASTAL WATERS...SMALL CRAFT
ADVISORIES AR LIKELY. NORTH TO NE FLOW WILL DEVELOP MONDAY NIGHT
INTO TUESDAY AS HIGH PRESSURE BUILDS OVER INTERIOR B.C. THE NORTHERN
INLAND WATERS MAY SEE GALES WITH FRASER RIVER OUTFLOW. WINDS WILL
EASE TUESDAY NIGHT. WEAK HIGH PRESSURE WILL BRING GENERALLY LIGHT
WINDS OVER THE WATERS ON WEDNESDAY. 33

&&

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

&&

$$

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






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