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

000
FXUS66 KSEW 230443
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
940 PM PDT WED OCT 22 2014

.SYNOPSIS...AN UPPER TROUGH WILL DIRECT SHOWERS INTO WESTERN
WASHINGTON THROUGH THURSDAY. THE SHOWERS WILL DECREASE THURSDAY
NIGHT. FRIDAY WILL BE A DRY DAY WITH WEAK HIGH PRESSURE AND OFFSHORE
FLOW. ANOTHER WEATHER SYSTEM WILL REACH THE AREA SATURDAY AFTERNOON
AND EVENING...WITH BLUSTERY WINDS DEVELOPING SATURDAY NIGHT.

&&

.SHORT TERM...AN UPPER TROUGH IS JUST OFFSHORE...SENDING SHOWERS
INTO THE REGION. A SURFACE TROUGH MOVED THROUGH WESTERN WA THIS
EVENING WITH LOCALLY HEAVY SHOWERS AND BLUSTERY WINDS...OLM-BLI WAS
+4MB AT 9PM. ANOTHER SURFACE TROUGH WILL REACH THE COAST AROUND 8AM
THU AND MOVE THROUGH THE INTERIOR OF WRN WA THRU MIDDAY. THE SHOWERS
WILL DECREASE THU NITE. TEMPORARY RIDGING MOVES OVER WRN WA FRIDAY
WITH LOW LEVEL OFFSHORE FLOW FOR A DRY DAY. ANOTHER SYSTEM MOVES
THRU THE AREA SATURDAY AFTERNOON AND NITE AND AS A SURFACE LOW MOVES
THROUGH WRN WA AND FILLS WINDS WILL BECOME BLUSTERY SAT NITE.

.LONG TERM...SHOWERS CAN BE EXPECTED BEHIND SATURDAY NIGHTS LOW
PRESSURE SYSTEM ON SUNDAY. BEYOND THAT TIME...MODELS ARE HAVING A
TOUGH TIME WITH THE DETAILS. THE ECMWF HAS A STORM TRACK TO THE
NORTH OF THE AREA WITH FRONTAL PASSAGES HERE THROUGH THE MIDDLE OF
NEXT WEEK. THE STORM TRACK ON THE GFS IS JUST TO THE SOUTH OF THE
AREA...STILL A WET ONE FOR WESTERN WASHINGTON BUT LESS WINDY. THE
CANADIAN SOLUTION IS CLOSER TO THE ECMWF. IN ANY CASE THE PATTERN
WILL REMAIN ACTIVE. ALBRECHT

&&

.HYDROLOGY...A FLOOD WARNING REMAINS IN EFFECT FOR THE SKOKOMISH
RIVER IN MASON COUNTY. THE SKOKOMISH AT POTLATCH CRESTED AROUND 17.2
FEET AT NOON TODAY. IT IS EXPECTED TO FALL BELOW FLOOD STAGE TONIGHT
AND GRADUALLY RECEDE THURSDAY THROUGH FRIDAY.

WET WEATHER IS EXPECTED TO CONTINUE THROUGH THE UPCOMING WEEK. BUT
RAINFALL AMOUNTS ARE NOT EXPECTED TO DRIVE ANY RIVERS ABOVE FLOOD
STAGE. ALBRECHT

&&

.AVIATION...COLD FRONT OVER THE CASCADES AT 04Z WILL CONTINUE TO
MOVE EAST. AIR MASS UNSTABLE WITH SOUTHWESTERLY FLOW ALOFT.

CEILINGS IN THE 4000 TO 6000 FOOT RANGE LOWERING DOWN TO NEAR 2000
FEET WITH VISIBILITIES 3-5SM IN SHOWERS. SHOWER ACTIVITY EASING UP
OVERNIGHT THEN INCREASING AGAIN THURSDAY MORNING INTO THE AFTERNOON
HOURS.

KSEA...CEILINGS NEAR 2000 FEET IN SHOWERS OTHERWISE CEILINGS IN THE
4000-6000 FOOT RANGE. SOUTHERLY WINDS 10-15 KNOTS WITH GUSTS NEAR 25
KNOTS UNTIL 06Z. FELTON

&&

.MARINE...COLD FRONT EAST OF THE WATERS THIS EVENING. PRESSURE RISES
BEHIND THE FRONT GIVING SMALL CRAFT ADVISORY SOUTHERLIES TO THE
INLAND WATERS INTO THE EARLY MORNING HOURS.

WEAK SURFACE RIDGE BUILDING OVER THE INLAND WATERS ON THURSDAY
SHIFTING EAST OF THE CASCADES ON FRIDAY. A 990 MB LOW WILL DEVELOP
OFF THE NORTHERN CALIFORNIA COAST AND MOVE INTO THE OREGON COASTAL
WATERS ON SATURDAY. THE LOW WILL CONTINUE TO MOVE NORTH INTO THE
INTERIOR OF WESTERN WASHINGTON SATURDAY NIGHT. THE TRACK OF THE LOW
WILL BE CRUCIAL IN HOW MUCH WIND DEVELOPS OVER THE MARINE AREAS. AT
THIS POINT GALE FORCE WINDS OR HIGHER ARE A GOOD POSSIBILITY
SATURDAY NIGHT INTO SUNDAY MORNING.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...FLOOD WARNING IN EFFECT FOR THE SKOKOMISH RIVER IN MASON
      COUNTY.

PZ...SMALL CRAFT ADVISORY IN EFFECT FOR HAZARDOUS IN EFFECT
     FOR THE COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH BAR IN EFFECT UNTIL 6 AM
     THURSDAY FOR THE GRAYS HARBOR BAR.
     SMALL CRAFT ADVISORY TONIGHT INLAND WATERS AND ADMIRALTY
     INLET.

&&

$$

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.