Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS66 KSEW 031054
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
252 AM PST TUE MAR 3 2015

.SYNOPSIS...AN UPPER LEVEL RIDGE OFFSHORE COMBINED WITH SURFACE HIGH
PRESSURE OVER BRITISH COLUMBIA WILL GIVE DRY WEATHER TO THE AREA
TODAY THROUGH WEDNESDAY. A WEAK FRONTAL SYSTEM WILL MOVE BY TO THE
NORTH OF THE AREA THURSDAY INTO EARLY FRIDAY. LOW RAIN CHANCES WILL
BE SMALL AND MAINLY CONFINED TO THE NORTHERN THIRD OF WESTERN
WASHINGTON. DRY AND MILD WEATHER WILL RETURN TO THE AREA LATER
FRIDAY INTO NEXT WEEKEND AS HIGH PRESSURE AT THE SURFACE AND ALOFT
BECOMES REESTABLISHED OVER THE AREA.

&&

.SHORT TERM...MEAN UPPER LEVEL RIDING IS ESTABLISHED ALONG 140W.
COLD AIR WELL OFF TO THE EAST OF THE RIDGE IS MOVING FROM THE
CANADIAN ARCTIC SOUTHWARD AND IS STAYING NICELY EAST OF THE ROCKIES
LIKE IT HAS MOST OF THIS WINTER.

A 1035 MB RIDGE IS OVER EAST CENTRAL BRITISH COLUMBIA EARLY THIS
MORNING. THIS HIGH IS GIVING DRY OFFSHORE FLOW TO THE AREA...BUT
OUTFLOW FROM THE FRASER RIVER VALLEY IS QUITE A BIT WEAKER THAN
MODELS INDICATED A FEW DAYS AGO. THE END RESULT IS COOL TO COLD
NIGHTS DUE TO STRONG RADIATIONAL COOLING AND THE DRY AIR MASS IN
PLACE...AND DAYTIME HIGHS NEAR NORMAL FOR THIS TIME OF YEAR.

THE RIDGE WILL WEAKEN ON WEDNESDAY AS THE OFFSHORE HIGH FLATTENS AND
SHIFTS EAST OVER THE AREA.

A VERY WEAK UPPER LEVEL SHORT WAVE TROUGH AND ASSOCIATED FRONTAL
SYSTEM WILL MOVE ONTO THE BRITISH COLUMBIA COAST LATER THURSDAY INTO
THURSDAY NIGHT THEN SHIFT EAST OF THE AREA EARLY FRIDAY MORNING. THE
GFS AND ECMWF SOLUTIONS HAVE TRENDED DRIER AS THE SHORT WAVE MOVES
OVER THE DOMINANT RIDGE...BUT A CHANCE OF LIGHT PRECIPITATION CANNOT
BE RULED OUT FROM A FORKS-OAK HARBOR-STEVENS PASS LINE NORTHWARD.
WITH THE INCREASE IN CLOUD COVER...NIGHTTIME LOWS WILL MODERATE INTO
THE 30S TO LOWER 40S. ALBRECHT

.LONG TERM...ALL GLOBAL MODELS FORM ANOTHER UPPER LEVEL RIDGE...THIS
TIME AROUND 130W...STARTING LATER FRIDAY AND MAINTAIN IT THROUGH THE
WEEKEND. SURFACE HIGH PRESSURE WITH HIGH HEIGHTS...A MILD AIR
MASS...AND ABUNDANT MARCH SUNSHINE...WILL RESULT IN MILD
TEMPERATURES WITH HIGHS IN THE 50S TO LOWER 60S AND LOWS AROUND 40.
IT LOOKS DRY NEXT WEEKEND THROUGH EARLY NEXT WEEK. ALBRECHT

&&

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

&&

.AVIATION...DRY NORTHERLY FLOW WILL PREVAIL ACROSS WESTERN WA TODAY.
THE AIR MASS IS DRY AND STABLE. VFR CONDITIONS EXPECTED. SKIES WILL
REMAIN CLEAR TONIGHT. 33

KSEA...N SURFACE WINDS TODAY WITH CLEAR SKIES. VFR CONDITIONS WILL
CONTINUE. 33

&&

.MARINE...HIGH PRES OVER WESTERN CANADA IS GIVING N/NE FLOW ACROSS
WESTERN WA TODAY. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE
NORTHERN INLAND WATERS...CENTRAL AND WEST STRAIT OF JUAN DE FUCA AND
THE NORTHERN COASTAL WATERS. WINDS WILL EASE THIS AFTERNOON. HIGH
PRESSURE WILL GIVE GENERALLY LIGHT WINDS OVER THE WATERS THROUGH THE
END OF THE WEEK. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY NORTHERN INLAND WATERS...CENTRAL AND WEST
      STRAIT OF JUAN DE FUCA...NORTHERN COASTAL WATERS.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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













USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.