Small Craft Advisory 129, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT THU JUN 12 2014

.SYNOPSIS...SOME SHOWERS WILL CONTINUE OVER THE AREA AS A DEEP UPPER
LOW MOVES ACROSS WASHINGTON TONIGHT AND THEN INTO SOUTHERN ALBERTA
ON FRIDAY. HIGH PRESSURE ALOFT WILL PREVAIL ON SATURDAY ALONG WITH
ONSHORE FLOW. EXPECT A WEAK LOW PRESSURE SYSTEM TO MOVE OVER THE
REGION ON SUNDAY. THE OVERALL WEATHER PATTERN FRIDAY THROUGH THIS
WEEKEND WILL BE COOL AND UNSETTLED.

&&

.SHORT TERM...A 5550 METER UPPER LOW IS MOVING INTO THE SOUTHWEST
CORNER OF WASHINGTON THIS EVENING. SHOWERS ROTATING AROUND THE LOW
CONTINUE TO BRING AREAS OF PRECIPITATION TO OUR FORECAST AREA...
WITH THE HEAVIEST AMOUNTS OVER THE SOUTHWEST INTERIOR AND THE
CASCADES. THUNDERSTORMS DEVELOPED ALONG THE CASCADE CREST THIS
AFTERNOON...WHICH ARE NOW DECREASING AND MOVE NORTH INTO BRITISH
COLUMBIA. THERE HAVE BEEN FEW OR NO STRIKES OVER THE LOWLANDS OF THE
FORECAST AREA SO FAR.

THE UPPER LOW WILL MOVE EAST JUST ACROSS THE CASCADES TONIGHT...THEN
TRACK NORTHEAST INTO NORTHWEST MONTANA OR SOUTHERN ALBERTA LATE
FRIDAY. THE FLOW ALOFT OVER WESTERN WASHINGTON WILL VEER TO
NORTHWEST AND THEN NORTH AS THE LOW MOVES AWAY. HOWEVER FAIRLY
STRONG ONSHORE FLOW...CONTINUING WEAK INSTABILITY...AND MOISTURE
WRAPPING AROUND THE LOW WILL MAKE FOR A SHOWERY AND FAIRLY COOL
FRIDAY.

SHOWERS WILL DECREASE FRIDAY NIGHT AND SATURDAY...AS A SMALL
PROGRESSIVE UPPER RIDGE MOVES INTO THE PACIFIC NORTHWEST. THE AIR
MASS WILL DRY AND STABILIZE. THERE WILL BE A CHANCE OF SHOWERS
STILL...BUT ANY PRECIPITATION THAT DOES OCCUR SHOULD BE FAIRLY LIGHT
AND SPOTTY. THERE WILL LIKELY BE FEW IF ANY SUN BREAKS...AND HIGH
TEMPERATURES WILL AGAIN BE ONLY IN THE UPPER 50S AND 60S.

ANOTHER UPPER TROUGH WILL REACH THE AREA SUNDAY FOR AN INCREASE IN
SHOWERS OVER WESTERN WASHINGTON.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
FORECAST DISCUSSION -- BEYOND SUNDAY...CONFIDENCE IN THE FORECAST
REMAINED LOW DUE TO CONTINUED DISAGREEMENT AND LACK OF CONSISTENCY
IN THE MEDIUM RANGE SOLUTIONS. FOR THIS REASON...HAVE CHOSEN TO MAKE
LITTLE CHANGE IN THE INHERITED FORECAST.

&&

.AVIATION...AN UPPER LEVEL LOW CENTER IS OVER SW WA THIS EVENING. IT
WILL SHIFT EAST OVER EASTERN WA BY DAYBREAK AND TO WRN MONTANA FRI
NIGHT. THE AIR IS MOIST AND UNSTABLE WITH SHOWERS OVER WRN WA THAT
WILL CONTINUE INTO FRIDAY. CIGS WILL LOWER AND SPREAD OUT OVERNIGHT
IN ONSHORE FLOW AND INCREASING MOISTURE WITH THE SHOWERS.

KSEA...SHOWERS SHOULD CONTINUE AT TIMES INTO FRIDAY AND THEN TAPER
OFF FRIDAY AFTERNOON. THE WIND MAY NOT STAY SWLY THROUGH ALL OF
FRIDAY SO WILL LOOK AT THAT LATER...EVENTUALLY IT MAY COME AROUND TO
NW...PERHAPS LATE FRIDAY IF THERE IS PSCZ ACTIVITY.

&&

.MARINE...THERE IS ONSHORE FLOW INTO WRN WA AND A 1002MB LOW OVER
EASTERN WA THIS EVENING. THERE IS A SMALL CRAFT ADVISORY UP FOR THE
CENTRAL AND EASTERN STRAIT AND THERE IS A GOOD CHANCE THAT RACE
ROCKS WILL REACH GALES DURING THE DAY FRIDAY...AND A GALE WATCH IS
UP FOR THAT.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT TIL 11 AM FRI FOR THE CENTRAL
     AND EASTERN STRAIT OF JUAN DE FUCA.

     GALE WATCH IN EFFECT FROM FRI MORNING THROUGH FRI EVENING FOR
     THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.

&&

YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML