Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 240513
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
920 PM PST FRI JAN 23 2015

.SYNOPSIS...A WARM FRONT OVER WESTERN WASHINGTON WILL SHIFT NORTH
INTO BRITISH COLUMBIA SATURDAY AFTERNOON. HIGH PRESSURE WILL GIVE
DRY AND MILD WEATHER TO THE AREA SUNDAY AND MONDAY. WEAK FRONTS WILL
REACH THE AREA LATER TUESDAY THROUGH THURSDAY.
&&

.SHORT TERM...RAINFALL OVER THE PAST 24HRS HAS BEEN AROUND 3 INCHES
OVER THE SW PORTION OF THE OLYMPICS. RAINFALL IN THE CASCADES HAS
BEEN IN THE 1-3 INCH RANGE IN THE NORTH AND CENTRAL CASCADES...THAT
IS PRETTY WET AND THE RIVERS ARE RISING BUT THE RAIN TONIGHT AND
SATURDAY MORNING WILL DRY UP SATURDAY AFTERNOON AS THE WARM
ADVECTION PRECIP SHIFTS NORTH INTO BRITISH COLUMBIA. FLOODING IS NOT
EXPECTED. THE UPPER RIDGE CENTER WILL SHIFT FROM JUST OFF NRN CALIF
TONIGHT TO SRN IDAHO LATER THIS WEEKEND. THE AIR WILL WARM AND DRY
LATER SATURDAY THROUGH SUNDAY AND THE FORECAST SHOWS CLEARING AND
MILD DAYTIME HIGH TEMPS SAT THROUGH MON.

.LONG TERM...PREVIOUS DISCUSSION...A VERY WEAK FRONT AND ASSOCIATED
WEAK SHORT WAVE TROUGH ALOFT WILL MOVE THROUGH THE AREA LATE TUESDAY
INTO WEDNESDAY AND WILL LIKELY BE FOLLOWED BY ANOTHER WEAK FRONT
WEDNESDAY NIGHT INTO THURSDAY. TEMPERATURES ALOFT WILL BE WARM
THROUGH THE PERIOD...SO SNOW LEVELS IN THE MOUNTAINS WILL REMAIN
RATHER HIGH...6000 FEET ON TUESDAY FALLING TO AROUND 4000 FEET BY
THURSDAY. IF YOU LIKE RIDGES AND MILD WEATHER THIS TIME OF
YEAR...THE PATTERN APPEARS TO BE SETTING UP FOR A REDEVELOPING RIDGE
LATE NEXT WEEK INTO NEXT WEEKEND WITH LIGHT LOW LEVEL OFFSHORE FLOW
AND QUITE MILD CONDITIONS FOR LATE JANUARY. ALBRECHT

&&

.HYDROLOGY...RAINFALL OVER THE PAST 24HRS IS FILLING UP MANY OF THE
WRN WA RIVERS ONCE AGAIN. RAIN HAS INCREASED OVER THE SW PORTION OF
THE OLYMPICS AGAIN WHERE RATES ARE AROUND 0.2 AN HOUR THIS EVENING.
THE MOST FLOOD PRONE SKOKOMISH RIVER IS NOT EXPECTED TO GET ABOVE
FLOOD STAGE BUT IT WILL BE WORTH WATCHING THE GAGE OVERNIGHT.

&&

.AVIATION...WESTERLY FLOW ALOFT CONTINUING THROUGH SATURDAY. A WARM
FRONT OVER THE AREA WILL WEAKEN TONIGHT THEN MOVE NORTH ON SATURDAY
AS AN UPPER RIDGE BUILDS. AIR MASS MOIST AND STABLE.

CEILINGS GENERALLY IN THE 1500-2500 FOOT RANGE THIS EVENING WITH
AREAS OF VISIBILITY 3-5SM IN LIGHT RAIN AND FOG AND ISOLATED
CEILINGS BELOW 1000 FEET. SATELLITE IMAGERY SHOWS A SECONDARY
IMPULSE JUST OFFSHORE THAT WILE MOVE INLAND OVERNIGHT KEEPING THE
CONDITIONS SIMILAR TO WHAT THEY ARE NOW WITH THE POSSIBILITY OF SOME
DETERIORATION IN THE EARLY MORNING HOURS SATURDAY. SLOW IMPROVEMENT
SATURDAY AFTERNOON WITH SIGNIFICANT CLEARING SATURDAY NIGHT WITH THE
FRONT NORTH OF THE AREA.

KSEA...DISCUSSION ABOVE APPLIES. MAINLY MVFR TONIGHT THROUGH
SATURDAY AFTERNOON. SOUTHERLY WIND 6-12 KT. FELTON

&&

.MARINE...A WARM FRONT OVER THE AREA TONIGHT WILL MOVE NORTH ON
SATURDAY. SURFACE HIGH PRESSURE WILL BUILD FROM THE SOUTH SATURDAY
AND SATURDAY NIGHT WITH THE LOW LEVEL FLOW BECOMING LIGHT OFFSHORE
ON SUNDAY. THE LIGHT OFFSHORE FLOW PATTERN WILL CONTINUE INTO
MONDAY. SMALL CRAFT ADVISORY WINDS WILL OCCUR AT TIMES OVER ALL
WATERS EXCEPT THE CENTRAL STRAIT THROUGH SATURDAY AFTERNOON. WINDS
WILL EASE ACROSS THE WATERS SATURDAY NIGHT WITH LIGHT WINDS SUNDAY.
A WEAK FRONT MAY MOVE INTO THE AREA TUESDAY.

KING TIDES...THE HIGHEST HIGH TIDES OF THE YEAR...ARE OCCURRING. THE
FORECAST HIGH TIDES FOR SEATTLE THIS MORNING AND SATURDAY MORNING
ARE 13.2 FEET. MINOR TIDAL OVERFLOW STARTS AT 13.5 FEET. SEA LEVEL
PRESSURE WAS QUITE HIGH THIS MORNING...AROUND 1030 MB...WITH LIGHT
WINDS. THIS GAVE A NEGATIVE TIDAL ANOMALY OF 0.8 FEET DURING THE
TIME OF HIGH TIDE AT 710 AM FRIDAY MORNING. THE HIGH TIDE ENDED UP
BEING ONLY 12.4 FEET.

SIMILAR METEOROLOGICAL CONDITIONS ARE EXPECTED DURING THE SATURDAY
MORNING HIGH TIDE AT 750 AM. THERE WILL BE A NEGATIVE TIDAL ANOMALY
AND THE UPSHOT IS MINOR TIDAL OVERFLOW IS NOT EXPECTED ON SATURDAY
EITHER. CHB/FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY ALL WATERS EXCEPT THE CENTRAL STRAIT.
     SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR BAR.
&&

$$

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