Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 251118
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 AM PST SUN JAN 25 2015

.SYNOPSIS...AN UPPER RIDGE IS OVER THE REGION. A WEAK FRONT WILL
DISSIPATE OVER WESTERN WASHINGTON TUESDAY. ANOTHER UPPER LEVEL RIDGE
WILL BUILD OVER THE REGION LATER IN THE WEEK.

&&

.SHORT TERM...SATELLITE IMAGERY AND OBS SHOW MOST THE AREA IS SOCKED
IN WITH LOW CLOUDS AND FOG THIS MORNING. MOS GUIDANCE AND BUFFER
SOUNDINGS INDICATE THIS WILL MOSTLY BURN OFF AROUND MIDDAY OR EARLY
AFTERNOON. THE EXCEPTION MAY BE PARTS OF THE SW INTERIOR/S PUGET
SOUND WHICH MAY STAY SOCKED IN ALL DAY. THIS SEEMS REASONABLE GIVEN
THE LACK OF FLOW AND RESIDUAL MOISTURE TRAPPED IN THE LOW LEVELS.
HIGHS THIS AFTERNOON WILL REACH THE UPPER 50S TO AROUND 60 UNDER
PARTLY TO MOSTLY SUNNY SKIES. A FEW SPOTS WILL LIKELY SEE RECORD
HIGHS SET FOR THE DATE. THE RECORD FOR SEA-TAC TODAY IS 58 SET IN
1986 WITH 60 DEGREES FORECAST.

HIGH PRESSURE WILL DOMINATE THE PAC NW THROUGH MONDAY. WARMER AIR
ALOFT WILL STRENGTHEN INVERSIONS KEEPING MOISTURE TRAPPED NEAR THE
SURFACE. THIS WILL RESULT IN AREAS OF FOG LATER TONIGHT AND MONDAY
MORNING. SHELTERED LOCATIONS LIKE OLYMPIA WILL AGAIN HAVE A TOUGH
TIME BREAKING OUT BUT MUCH OF THE AREA WILL SEE SOME AFTERNOON
SUNSHINE. HIGHS WILL BE SIMILARLY MILD IN THE 50S.

THE UPPER RIDGE SHIFTS EWD MONDAY NIGHT AS A FRONT APPROACHES THE
REGION. 00Z/06Z MODELS ARE A BIT FASTER THAN SOME PAST RUNS SHOWING
LIGHT RAIN SPREADING INTO WRN WA DURING THE MORNING. THE FRONT WILL
THEN DISSIPATE OVER THE AREA TUESDAY NIGHT. HIGHS WILL BE A BIT
COOLER IN THE LOWER 50S.

.LONG TERM...A FEW SHOWERS WILL LINGER INTO WEDNESDAY WITH ABUNDANT
RESIDUAL MOISTURE OVER THE AREA. THE MODELS HAVE TRENDED DRIER
OVERALL WITH MUCH LESS QPF. WILL KEEP THE CHANCE POPS IN PLACE FOR
NOW. BOTH THE GFS/ECMWF CONTINUE TO SHOW A STRONGER RIDGE ON
THURSDAY WHICH WOULD GIVE DRY WEATHER. THE FORECAST WAS ADJUSTED TO
REMOVE POPS OVER THE INTERIOR. THE RIDGE WILL PERSIST WILL PERSIST
FRIDAY AND SATURDAY FOR CONTINUED DRY AND MILD WEATHER. MERCER

&&

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

&&

.AVIATION...UPPER LEVEL RIDGE OVER WESTERN WASHINGTON TODAY WITH
WITH WESTERLY FLOW ALOFT. SURFACE FLOW BECOMING LIGHT OFFSHORE LATER
TODAY WITH SURFACE HIGH OVER THE AREA SHIFTING EAST. AIR MASS MOIST
AND STABLE WITH A DRYING TREND THIS AFTERNOON.

WIDESPREAD CEILINGS BELOW 1000 FEET WITH LOCAL VISIBILITIES AS LOW
AS A HALF MILE EARLY THIS MORNING. LITTLE CHANGE IN THE CONDITIONS
UNTIL LATE MORNING WITH RAPID IMPROVEMENT THIS AFTERNOON AS THE LOW
LEVEL FLOW BECOMES OFFSHORE. BY MID AFTERNOON EXPECT VFR CONDITIONS
ACROSS THE AREA WITH JUST SOME HIGH CLOUDS.

KSEA...CEILINGS AOB 500 FEET WITH VISIBILITIES 3-5SM UNTIL 18Z-20Z.
NO VISIBILITY RESTRICTIONS AFTER 20Z WITH THE LOW CLOUD LAYER
SCATTERING OUT. JUST HIGH CLOUDS OVER THE TERMINAL BY MID
AFTERNOON.  LIGHT SOUTHERLY WINDS BECOMING VARIABLE MIDDAY. FELTON

&&

.MARINE...SURFACE HIGH PRESSURE WILL SHIFT EAST OF THE CASCADES THIS
MORNING WITH THE LOW LEVEL FLOW BECOMING LIGHT OFFSHORE. THE LIGHT
OFFSHORE FLOW PATTERN WILL CONTINUE INTO MONDAY. A WEAKENING FRONT
WILL ARRIVE ON TUESDAY WITH SURFACE HIGH PRESSURE REBUILDING OVER
THE AREA WEDNESDAY AND THURSDAY.

SMALL CRAFT ADVISORIES FOR HAZARDOUS SEAS FOR THE OUTER COASTAL
WATERS WILL CONTINUE INTO THIS EVENING. FELTON

&&

.MARINE...SURFACE HIGH PRESSURE WILL SHIFT EAST OF THE CASCADES THIS
MORNING WITH THE LOW LEVEL FLOW BECOMING LIGHT OFFSHORE. THE LIGHT
OFFSHORE FLOW PATTERN WILL CONTINUE INTO MONDAY. A WEAKENING FRONT
WILL ARRIVE ON TUESDAY WITH SURFACE HIGH PRESSURE REBUILDING OVER
THE AREA WEDNESDAY AND THURSDAY.

SMALL CRAFT ADVISORIES FOR HAZARDOUS SEAS FOR THE OUTER COASTAL
WATERS WILL CONTINUE INTO THIS EVENING. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY HAZARDOUS SEAS OUTER COASTAL WATERS.

&&

$$

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