Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 282210
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT SUN SEP 28 2014

.SYNOPSIS...A FRONT WILL BRING RAIN TO THE COAST MONDAY MORNING AND
TO THE INTERIOR OF WESTERN WASHINGTON BY THE AFTERNOON. SCATTERED
SHOWERS MONDAY NIGHT WILL TAPER OFF BY MIDWEEK. AN UPPER RIDGE OF
HIGH PRESSURE IS LIKELY TO BUILD OVER THE AREA LATE IN THE WEEK.

&&

.SHORT TERM...AT 3PM THE PUDDLE OF LOW CLOUDS THAT HAS BEEN
SHRINKING THIS AFTERNOON DID NOT HAVE TOO MUCH LEFT TO GO TO BURN
OFF AND IT OUGHT TO BE GONE BY LATE AFTERNOON. AFTER A MOSTLY CLEAR
NIGHT CLOUDS WILL INCREASE RAPIDLY AROUND DAYBREAK MONDAY AHEAD OF A
COLD FRONT. IT WILL RAIN ON THE COAST IN THE MORNING AND IN THE
INTERIOR MIDDAY AND AFTERNOON. AN UPPER TROUGH AND ONSHORE FLOW WILL
GIVE SCATTERED SHOWERS MONDAY NIGHT AND TUESDAY...PETERING OUT TUE
NIGHT AND WED AS HEIGHTS RISE A BIT. ANOTHER SYSTEM MOVING INTO B.C.
ON WED SHOULD NOT HAVE MUCH EFFECT OVER WA AND THE 500MB HEIGHT
RISES TO AROUND 5700M IN WNW FLOW ALOFT. WE MAY SEE SOME PSCZ
ACTIVITY AT TIMES TUE AND WED IN THAT PATTERN HOWEVER.

.LONG TERM...AN UPPER RIDGE WILL BUILD OVER THE PACIFIC NORTHWEST
THURSDAY AND FRI AND WILL PROBABLY REMAIN IN PLACE FOR THE WEEKEND.
THERE IS A SYSTEM THAT MOVES INTO B.C. AND MOISTURE FROM THAT SYSTEM
MAY WORK SOUTH INTO WRN WA BY SAT. UPPER LEVEL HEIGHTS LOOK LIKE
THEY OUGHT TO BE HIGH ENOUGH FOR THE RIDGE TO BE ASSOCIATED WITH
SUNNY WARM WEATHER BUT THE MODELS HAVE OFTEN SHOWN A LITTLE RAIN
DESPITE THE HIGH HEIGHTS. WITH TROPICAL MOISTURE FROM A WESTPAC
TYPHOON GETTING INTO THE FLOW IT IS PROBABLY TOO EARLY TO SAY WHAT
WILL HAPPEN YET BUT NUDGED THE FORECAST TOWARD THE DRIPPY CLOUDY
MODELS.

&&

.AVIATION...AN UPPER LEVEL LOW CONTINUES TO SPIN OVER THE GREAT
BASIN THIS AFTERNOON...WHILE AN UPPER LEVEL RIDGE NUDGES EAST INTO
WASHINGTON. THE FLOW ALOFT IS WESTERLY. THE AIR MASS ACROSS WESTERN
WA IS STABLE. LOW CLOUDS ARE SLOW TO BURN OFF ACROSS THE INTERIOR
THIS AFTERNOON WITH SCT-BKN010 OVER PUGET SOUND. THE LOW CLOUDS WILL
SCATTER LATE THIS AFTERNOON AND EVENING...THEN REFORM OVERNIGHT. SO
EXPECT MVFR TO IFR CONDITIONS AGAIN BY 12Z. A COLD FRONT WILL SWEEP
THROUGH THE REGION ON MON BRINGING SHOWERS TO THE AREA. 33

KSEA...LOW CLOUDS NEAR 1000 FT WILL ERODE LATE THIS AFTERNOON. WILL
LIKELY SEE A FEW HOURS OF CLEARING THIS EVENING...THEN LOW CLOUD
WILL REFORM OVERNIGHT. NORTHERLY WINDS WILL SWITCH TO SOUTHERLY BY
06Z. EXPECT RAIN AT THE TERMINAL BY 21Z. 33

&&

.MARINE...A WEAK ONSHORE PUSH WILL BRING WESTERLY SMALL CRAFT
ADVISORY WINDS TO THE CENTRAL AND EAST STRAIT TONIGHT. A COLD FRONT
WILL CROSS WESTERN WA ON MON...WITH ONSHORE FLOW INCREASING BEHIND
THE FRONT MON AFTERNOON AND EVENING. WESTERLY GALES ARE POSSIBLE
THROUGH THE STRAIT. ONSHORE FLOW WILL PREVAIL TUE AND WED...THEN
WEAKEN ON THU AS HIGH PRES SHIFTS INLAND. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT OF JUAN DE FUCA.

&&

$$

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