Funnel Cloud in Washington, June 4, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT FRI JUN 4 2010

.SYNOPSIS...DRIER AND WARMER WEATHER IS EXPECTED ON SATURDAY AS A
WEAK RIDGE BUILDS. MORE RAIN IS POSSIBLE ON SUNDAY AS A WEATHER
SYSTEM MOVES THROUGH OREGON AND CLIPS WESTERN WASHINGTON. MONDAY AND
MONDAY NIGHT LOOK MOSTLY DRY...THEN ANOTHER SYSTEM ARRIVES ABOUT
TUESDAY NIGHT. WEATHER WILL REMAIN UNSETTLED NEXT WEEK.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS GOOD CLEARING COAST STRAIT AND
SOUTHWEST INTERIOR. SOME CUMULUS POPPED UP AS CLOUDS ASSOCIATED WITH
AN EXITING SYSTEM DISSIPATED. THE CUMULUS WILL EVAPORATE OVERNIGHT
AND SATURDAY LOOKS LIKE A MOSTLY SUNNY DAY...POSSIBLY AFTER LOCAL
MORNING STRATUS. HIGHS WILL BE MOSTLY IN THE 60S WITH A FEW LOW 70S.

MODELS ARE IN SOME DISAGREEMENT ABOUT SUNDAY...BUT THE MAIN IDEA
SEEMS TO BE THAT A WEATHER SYSTEM WILL MOVE NORTHEAST THROUGH OREGON
AND CLIP PART OF WESTERN WASHINGTON. HAVE PUT SOME POPS IN THE
SOUTHERN AND EASTERN SECTIONS SATURDAY NIGHT...AND SPREAD THE POPS
NORTH ON SUNDAY. STILL HAVE SOME DRY PARTS NORTH AND WEST ON SUNDAY
HOWEVER. HIGHS WILL BE A BIT LOWER...IN THE 60S.

AFTER BROAD BRUSH CHANCE OF SHOWERS SUNDAY NIGHT...SHOWERS SHOULD
RETREAT TO THE CASCADES MONDAY. THE FORECAST IS FOR DRY WEATHER
MONDAY WITH SOME SUN...AND HIGHS BACK IN THE 60S AND LOWER 70S. BURKE

.LONG TERM...TUESDAY IS ALSO MOSTLY DRY...BUT THE GFS HAS SOME RAIN
SPREADING IN FROM THE SOUTH ON TUESDAY AFTERNOON. RATHER THAN TRY TO
PIN IT ALL DOWN...HAVE PUT A CHANCE OF RAIN EVERYWHERE ON TUESDAY.
AFTER THAT THE FORECAST IS A BROAD BRUSH OF MOSTLY CLOUDY WITH A
CHANCE OF SHOWERS. TEMPERATURES WILL NOT BE TOO FAR FROM CLIMATOLOGY
WITH HIGHS IN THE 60S AND LOWS IN THE 40S AND 50S. BURKE

&&

.AVIATION...W FLOW ALOFT WILL CONTINUE OVER W WA TONIGHT AND
SATURDAY. THE AIR MASS IS GRADUALLY DRYING AND CIGS HAVE BEEN
RISING. NO PUGET SOUND CONVERGENCE ZONE HAS FORMED YET...BUT ONE IS
STILL POSSIBLE THIS EVENING. OVERNIGHT COOLING WILL ALLOW AREAS OF
MVFR STRATUS TO REFORM LATE TONIGHT...PARTICULARLY AROUND PUGET
SOUND. CONTINUED DRYING OF THE AIR MASS AS A FLAT WEAK UPPER LEVEL
RIDGE MOVES OVER THE AREA ON SATURDAY SHOULD LEAD TO CLEARING
18Z-20Z.

KSEA...CIGS HAVE RISEN ABOVE BKN050 AND WILL KEEP THEM THERE THROUGH
THE EVENING. COULD SEE SCT060 AT TIMES. NO CONVERGENCE ZONE HAS
FORMED YET...AND THOUGH THERE IS STILL A POSSIBILITY...LATEST
GUIDANCE SUGGESTS IT WILL STAY FURTHER NORTH...FROM N SEATTLE
NORTHWARD. SURFACE WINDS HAVE GONE S AND THE INCREASING SW PRESSURE
GRADIENT THIS AFTERNOON WILL SHIFT THE WIND AROUND TO SW 5-10 KT AND
KEEP IT THERE THIS EVENING. EXPECT MVFR STRATUS TO REFORM AFTER 09Z
TONIGHT. KAM

&&

.MARINE...ONSHORE FLOW IS SLOWLY INCREASING. SCA WINDS HAVE ALREADY
DEVELOPED IN THE STRAIT OF JUAN DE FUCA. FORECAST TREND LOOKS ON
TRACK WITH THE SURFACE RIDGE JUST OFFSHORE BUILDING IN OVER W WA AS
A 1022 MB SURFACE HIGH BY 12Z SATURDAY. SO THE ONSHORE FLOW WILL
DECREASE RAPIDLY LATE TONIGHT. THE WEAK PRESSURE GRADIENT PATTERN
WILL CONTINUE THROUGH SUNDAY AS THE SURFACE HIGH MOVES N OVER
B.C...WHILE A SURFACE LOW MOVES E ACROSS OREGON SUNDAY MORNING. THE
ONSHORE FLOW PATTERN RETURNS FOR MOST OF NEXT WEEK...DOMINATED BY A
LARGE SURFACE RIDGE OFFSHORE. SWELL ON THE COAST IS JUST LOW ENOUGH
SO THAT THE SCA FOR ROUGH BAR CONDITIONS CAN BE DROPPED. KAM

&&

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

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.