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000
FXUS66 KSEW 111117 CCA
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
415 AM PDT TUE JUN 11 2013

.SYNOPSIS...A WEAK UPPER LEVEL LOW OFF OF VANCOUVER ISLAND THIS
MORNING WILL MOVE SOUTHEAST TO NEAR THE NORTH COAST LATER TODAY AND
TONIGHT. THE LOW WILL HANG UP OVER WESTERN WASHINGTON ON WEDNESDAY
THEN DROP SOUTH INTO OREGON ON THURSDAY. THE LOW WILL DRIFT EASTWARD
ON FRIDAY. THE UPPER LOW WILL BRING CLOUDS...COOL TEMPERATURES...AND
A SOMEWHAT SHOWERY WEATHER PATTERN FOR MUCH OF THE UPCOMING WEEK.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS CLOUDS OVER WESTERN WASHINGTON
THIS MORNING WITH AN UPPER LEVEL LOW JUST SOUTHWEST OF THE NORTHERN
TIP OF VANCOUVER ISLAND. DOPPLER RADARS PICKING UP SOME SHOWER
ACTIVITY ALONG AND JUST WEST OF THE COAST. TEMPERATURES AT 3 AM WERE
IN THE MID 40S TO MID 50S.

UPPER LEVEL LOW WILL DRIFT SOUTHEAST TODAY AND BY 00Z WED WILL BE
NEAR KUIL. SHOWERS SPINNING AROUND THE LOW WILL MOVE INTO WESTERN
WASHINGTON WITH THE BEST CHANCE FOR MEASURABLE PRECIPITATION ALONG
THE COAST. TEMPERATURES WITH THE CLOUD COVER WILL BE COOLER THAN THE
LAST FEW DAYS WITH MOST PLACES IN THE 60S.

LOW NOT MOVING MUCH TONIGHT INTO WEDNESDAY...THE CENTER REMAINING
NEAR KUIL. SHOWERS ROTATING AROUND THE LOW WILL CONTINUE TO MOVE
INTO WESTERN WASHINGTON WITH THE HIGHER POPS FOR THE INTERIOR
WEDNESDAY AFTERNOON. TEMPERATURES ALOFT COOLING SLOWLY AND BY LATER
WEDNESDAY THE SNOW LEVEL WILL BE DOWN AS LOW AS 4500 FEET IN THE
NORTH CASCADES BUT WITH THE PRECIPITATION AMOUNTS ASSOCIATED WITH
THE SHOWERS BEING FAIRLY LIGHT ONLY AN INCH OR TWO OF NEW SNOW FOR
THE MOUNTAINS. HIGH TEMPERATURES WILL ONCE AGAIN BE A FEW DEGREES
BELOW NORMAL ON WEDNESDAY...MOSTLY IN THE 60S.

MODEL SOLUTIONS FOR WEDNESDAY NIGHT AND THURSDAY SLIGHTLY DIFFERENT
WITH THE ECMWF KEEPING THE LOW OVER WESTERN WASHINGTON WHILE THE GFS
MOVES THE LOW INTO OREGON. EITHER SOLUTION WILL STILL KEEP AT LEAST
A CHANCE OF SHOWERS IN THE FORECAST ON THURSDAY. TEMPERATURES ALOFT
REMAINING COOL WITH THE SNOW LEVEL DOWN AROUND 5000 FEET BUT JUST
LIKE WEDNESDAY PRECIPITATION AMOUNTS WITH THE SHOWERS NOT VERY MUCH
KEEPING NEW SNOW ACCUMULATIONS ABOVE 5000 FEET LESS THAN A COUPLE OF
INCHES. HIGH TEMPERATURES WILL REMAIN ON THE COOL SIDE WITH 60S
COMMON.

.LONG TERM...EXTENDED MODELS IN GOOD AGREEMENT THURSDAY NIGHT AND
FRIDAY WITH THE LOW KICKING OUT TO THE EAST AND ANOTHER LOW MOVING
DOWN OFF THE COAST WEST OF 130W. LOW SPINS AROUND OFFSHORE SATURDAY
THEN DRIFTS EAST ON SUNDAY. FLOW ALOFT OVER WESTERN WASHINGTON
BECOMING SOUTHERLY ON SUNDAY. THIS OPENS UP THE POSSIBILITY OF
CONVECTION OVER THE CASCADES. LOW CONTINUES TO SPIN AROUND OFFSHORE
MONDAY WITH LITTLE CHANGE IN THE PATTERN. HIGH TEMPERATURES ON
FRIDAY AND SATURDAY REBOUNDING BACK TO NEAR NORMAL. AS THE LOW MOVES
CLOSER TO THE AREA MORE CLOUD COVER WILL DROP THE HIGH TEMPERATURES
BACK DOWN INTO THE 60S FOR THE MOST PART. FELTON

&&

.AVIATION...AN UPPER TROUGH WILL MOVE OVER THE NORTHEAST PACIFIC
WITH SOUTH TO SOUTHWEST FLOW ALOFT FOR WESTERN WASHINGTON. AT THE
SURFACE ONSHORE FLOW WILL CONTINUE WITH HIGH PRESSURE OFFSHORE AND
LOWER PRESSURE INLAND. A WEAK SURFACE TROUGH WILL FORM OVER THE
OFFSHORE WATERS TODAY. THE LOW LEVELS WILL BECOME INCREASINGLY MOIST
THIS MORNING. AIR MASS BECOMING SLIGHTLY UNSTABLE.

LOW CLOUDS WITH CEILINGS 4-6K FT WILL MOSTLY FILL IN EARLY THIS
MORNING. THERE SHOULD ALSO BE SOME 2-3K FT CEILINGS LATER THIS
MORNING. ANY LOW STUFF THAT FORMS SHOULD LIFT BACK TO 4-6K FT BY
AFTERNOON. LOWER CLOUDS WILL LIKELY REDEVELOP AGAIN LATE TONIGHT AS
MOIST ONSHORE FLOW CONTINUES. SCHNEIDER

KSEA...SOUTH/SOUTHWEST WIND 6-10 KNOTS...RISING TO 10-15 KNOTS THIS
AFTERNOON. SCHNEIDER

&&

.MARINE...HIGH PRESSURE OFFSHORE WITH LOWER PRESSURE INLAND WILL
MAINTAIN ONSHORE FLOW. A WEAK TROUGH WILL FORM OVER THE OFFSHORE
WATERS TODAY WHICH WILL KEEP WINDS BELOW SMALL CRAFT ADVISORY
STRENGTH IN THE STRAIT. THE TROUGH WILL SHIFT SLOWLY INLAND
WEDNESDAY AND THURSDAY WITH WESTERLY GRADIENTS THROUGH THE STRAIT
INCREASING AGAIN LATE IN THE WEEK. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

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