Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 272215
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST TUE JAN 27 2015

.SYNOPSIS...LOW LEVEL MOISTURE WILL LINGER ACROSS WESTERN WASHINGTON
TONIGHT AND WEDNESDAY FOR A CHANCE OF LIGHT RAIN. AN UPPER LEVEL
RIDGE WILL PROVIDE DRY AND MILD WEATHER THURSDAY THROUGH SATURDAY.
THE NEXT FRONT BRINGS RAIN BACK INTO THE AREA SUNDAY AND EARLY NEXT
WEEK.

&&

.SHORT TERM...A WEAK COLD FRONT DISSIPATED OVER WESTERN WA THIS
AFTERNOON FOR CLOUDY SKIES AND A FEW LIGHT SPRINKLES. PRECIP AMOUNTS
ARE LIGHT FROM A TRACE TO FEW HUNDREDTHS. LOW LEVEL MOISTURE WILL
LINGER ACROSS THE REGION TONIGHT WITH ISOLATED LIGHTS SHOWERS
CONTINUING.

STABLE WEATHER IS EXPECTED ON WEDNESDAY WITH WEAK RIDGING OVER THE
PAC NW. HOWEVER MODELS SHOW A WEAK SHORT WAVE TROUGH UNDERCUTTING
THE RIDGE. THIS FEATURE MAY SQUEEZE OUT A FEW LIGHT SPRINKLES AS IT
PASSES THROUGH. THE LOW LEVEL AIR MASS WILL REMAIN MOIST FOR CLOUDY
SKIES.

THE UPPER LEVEL RIDGE WILL STRENGTHEN OVER THE PAC NW THU AND FRI
FOR DRIER AND SLIGHTLY WARMER WEATHER. WE WILL LIKELY SEE MORNING
LOW CLOUDS AND FOG IN THE LOWLANDS...THEN PARTLY TO MOSTLY SUNNY
SKIES DURING THE AFTERNOON. HIGHS WILL RANGE FROM THE MID TO UPPER
50S. 33

.LONG TERM...AN UPPER LEVEL RIDGE WILL REMAIN DOMINANT ACROSS THE
PAC NW FRIDAY INTO THE WEEKEND WITH DRY WEATHER CONTINUING ACROSS
WESTERN WA. SATURDAY WILL LIKELY BE THE WARMEST DAY AND MAY SEE LOW
60S AGAIN. THE RIDGE WILL FLATTEN ON SUNDAY AS A WARM FRONT MOVES
INTO B.C. THIS FRONT MAY CLIP THE AREA FOR LIGHT RAIN. RAIN WILL
INCREASE SUN AFTERNOON AND EVENING AS A COLD FRONT MOVES IN. ZONAL
FLOW WILL PREVAIL MON AND TUE WITH UPPER LEVEL DISTURBANCES PASSING
THROUGH THE AREA. THIS KEEPS A CHANCE OF RAIN IN THE FORECAST
THROUGH AT LEAST MIDWEEK. 33

&&

.HYDROLOGY...FLOODING IS NOT EXPECTED FOR THE NEXT 7 DAYS.

&&

.AVIATION...MODERATE WESTERLY FLOW ALOFT WILL CONTINUE TONIGHT. AN
UPPER LEVEL RIDGE WILL BUILD OVER WESTERN WASHINGTON ON WEDNESDAY
GIVING LIGHTER FLOW ALOFT. AT THE SURFACE MODERATE ONSHORE FLOW WILL
EASE TONIGHT...THEN TURN WEAKLY OFFSHORE WEDNESDAY. A WEAK FRONT
DISSIPATED OVER THE AREA TODAY LEAVING A MOIST AND STABLE AIR MASS
WITH SPRINKLES OR DRIZZLE AT TIMES.

CEILINGS ARE GENERALLY AROUND 1000 FEET THOUGH THERE HAS BEEN SOME
IMPROVEMENT TO 2-3K FT IN THE FAR NORTHWEST THIS AFTERNOON. LITTLE
CHANGE IS LIKELY TONIGHT AS ONSHORE FLOW BRINGS MOISTURE INLAND AT
FIRST...THEN LIGHT FLOW KEEPS THE AIR MASS MOIST AND STAGNANT. IFR
CONDITIONS MAY BE BRIEFLY WIDESPREAD WEDNESDAY MORNING...BUT
OFFSHORE FLOW SHOULD BRING SIGNIFICANT IMPROVEMENT BY AFTERNOON.

KSEA...DISCUSSION ABOVE APPLIES. CEILING NEAR 1K FT WILL BECOME IFR
OVERNIGHT BEFORE IMPROVING WEDNESDAY AFTERNOON. SURFACE WINDS WILL
REMAIN SOUTHERLY 5-8 KT. CHB

&&

.MARINE...MODERATE WESTERLY FLOW WILL GIVE A FEW HOURS OF SMALL
CRAFT ADVISORY WINDS IN THE STRAIT THIS EVENING. AN ADVISORY IS IN
EFFECT FOR THIS AFTERNOON AND EVENING.

THE ONSHORE FLOW WILL WEAKEN TONIGHT. THE FLOW WILL BECOME WEAK
OFFSHORE ON WEDNESDAY AND THIS PATTERN WILL PERSIST THROUGH
SATURDAY. NEXT FRONT ARRIVES AROUND SUNDAY. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND WEST STRAIT.

&&

$$

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.