Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 302222
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
320 PM PDT SUN AUG 30 2015

.SYNOPSIS...AN UPPER LEVEL TROUGH WILL REMAIN OVER THE PACIFIC
NORTHWEST THROUGH THURSDAY. WEATHER SYSTEMS MOVING THROUGH THE
TROUGH WILL KEEP THE WEATHER COOL AND WET FOR THIS TIME OF YEAR.
THE TROUGH WILL WEAKEN AND MOVE INLAND TOWARD THE END OF THE WEEK.

&&

.SHORT TERM...SCATTERED SHOWERS AND PARTIAL CLEARING PERIODS THIS
EVENING WILL GIVE WAY TO WARM ADVECTION OVERNIGHT AS A FRONTAL
SYSTEM SAGS SOUTH TOWARD THE AREA. THE MOUNTAINS SHOULD GET A GOOD
SOAKING AND LIGHT RAIN IS A GOOD BET AT TIMES FOR THE LOWLANDS MON
AND TUE. SHOWERS OR RAIN BANDS WILL CONTINUE TO BE DIRECTED INTO THE
AREA BY THE UPPER TROUGH TUE NITE AND WED AND THE AIR COOLS ALOFT
AS AN UPPER LOW CENTER SHIFTS OVER SOUTHWEST BRITISH COLUMBIA.

.LONG TERM...WEAK IMPULSES ROTATING THROUGH THE UPPER TROUGH WILL
BRING A FEW PERIODS OF SHOWER ACTIVITY THROUGH LATE IN THE WEEK. THE
MONTAINS AND PSCZ SHOULD HAVE THE BEST CHANCE OF SHOWERS. THE
UPPER TROUGH SHOULD SHIFT INLAND IN TIME FOR THE WEEKEND FOR DRY
WEATHER AND SOME MORE SUNSHINE.

&&


.AAVIATION...ABUNDANT LOW LEVEL MOISTURE AND INSTABILITY SUPPORTING
SCATTERED SHOWERS OVER THE AREA...WITH VFR CEILINGS AND
VISIBILITIES. A WEAK FRONT WILL APPROACH THE AREA FROM THE NORTHWEST
TONIGHT...BRINING RAIN TO THE NORTH COAST AROUND
MIDNIGHT...SPREADING INLAND THROUGH THE MORNING. PREVIOUS MODEL RUNS
HAD RAIN INTO MOST OF THE INTERIOR TERMINALS BY 12Z. MID DAY RUNS A
BIT SLOWER...MORE LIKE MID MORNING FOR THE CENTRAL SOUND
TERMINALS...AND SOUTH BY MIDDAY. EXPECT VFR CONDITIONS TO LOWER TO
MVFR LEVELS THROUGH MONDAY MORNING AS THE FRONT WORKS INLAND. SOME
LOCATIONS MAY REACH IFR LEVELS...ESPECIALLY WITH RAINFALL OR JUST
AFTER RAIN.

KSEA...VFR CONDITIONS WILL PERSIST THIS AFTERNOON...POSSIBLY LOWERING
TO NEAR MVFR LEVELS WITH SHOWERS. OTHERWISE EXPECT PREVAILING VFR
THROUGH MUCH OF THE NIGHT...LOWERING EARLY MONDAY MORNING AS THE
FRONT WORKS INTO THE CENTRAL SOUND TO MVFR LEVELS. WINDS WILL REMAIN
SOUTHERLY 10 TO 12 KNOTS THIS EVENING...EASING SOMEWHAT TO 8 TO 10
KNOTS AROUND MIDNIGHT...THEN INCREASING AGAIN AROUND MIDDAY TO 10 TO
12 KNOTS.

&&

.MARINE...SOUTHERLY LOW LEVEL PRESSURE GRADIENTS WILL INCREASE
TONIGHT AS ANOTHER FRONTAL SYSTEM APPROACHES FROM THE NORTHWEST.
EXPECT SMALL CRAFT ADVISORY SOUTHERLY WINDS OVER ALL WATERS BUT THE
CENTRAL STRAIT BY LATE TONIGHT. SMALL CRAFT ADVISORY WINDS WILL
CONTINUE OVER THE INTERIOR WATERS MONDAY MORNING BEFORE EASING
MONDAY AFTERNOON. A SERIES OF WEAK SYSTEMS WILL MOVE THROUGH THE
AREA TUESDAY AND WEDNESDAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...NONE.

PZ...SMALL CRAFT ADVISORIES COAST...ENTRANCES TO THE STRAIT...
     ADMIRALTY INLET AND THE INLAND WATERS.

&&

$$

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