Gale Warning 50, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
835 PM PDT FRI JUL 19 2013

.SYNOPSIS...AN UPPER LEVEL RIDGE WILL REMAIN OVER THE WESTERN U.S.
THROUGH EARLY NEXT WEEK. THE RIDGE WILL WEAKEN OVER WASHINGTON BY
THE MIDDLE OF NEXT WEEK AS AN UPPER LEVEL LOW BECOMES CENTERED NEAR
JUNEAU.

&&

.SHORT TERM...A TYPICAL SUMMER REGIME IS IN PLACE. THERE IS A STRONG
UPPER RIDGE CENTERED NEAR SAN FRANCISCO AND A BIT OF A RIDGE AXIS
EXTENDS NORTH ALONG THE WA AND OREGON COAST. THERE IS A LARGE AREA
OF COASTAL STRATUS OFFSHORE AND ALONG THE COAST AND THE STRATUS WILL
SPREAD INLAND BY DAYBREAK EACH MORNING...REACHING THE METRO AREA BUT
PROBABLY NOT EXTENDING VERY FAR INTO THE CASCADES EXCEPT FOR THE
LOWER FOOTHILLS. THE MARINE AIR WILL REMAIN SHALLOW ENOUGH TO
CONTINUE TO BURN BACK TO THE COAST...WITH HIGHS IN THE 60S ON THE
COAST TO THE LOWER 80S IN THE INTERIOR OF WESTERN WA AWAY FROM THE
WATER. LITTLE CHANGE IS EXPECTED THROUGH MONDAY.

.LONG TERM...BY THE MIDDLE OF NEXT WEEK THE RIDGE OVER THE WESTERN
U.S. WILL PROBABLY WEAKEN WHILE AN UPPER LOW MOVES TO THE ALASKA
PANHANDLE/NRN B.C. COAST. DAYTIME TEMPS WILL LIKELY FALL OFF A NOTCH
THROUGH THE MIDDLE OF NEXT WEEK OVER WESTERN WA...THE NIGHT AND
MORNING CLOUDS WILL PROBABLY BE SLOWER TO PULL BACK TOWARD THE COAST
EACH DAY AND THE MARINE AIR WILL LIKELY BE DEEPER BY WED.

&&

.AVIATION...LIGHT WESTERLY FLOW ALOFT OVER WESTERN WASHINGTON THIS
EVENING WILL CONTINUE TONIGHT AND SATURDAY...AS A BROAD UPPER RIDGE
REMAINS OVER THE REGION. LOW LEVEL ONSHORE FLOW WILL CONTINUE AS
WELL. THE AIR MASS WILL BE STABLE AND DRY EXCEPT FOR THE MOIST
SHALLOW SURFACE-BASED MARINE LAYER.

MARINE STRATUS CLEARED BACK TO THE COAST THIS AFTERNOON...BUT IT HAS
STARTED TO MOVE INLAND AGAIN THIS EVENING. STRATUS WILL CONTINUE TO
MOVE INLAND TONIGHT...AND ITS COVERAGE OVER THE WESTERN WASHINGTON
INTERIOR LOWLANDS SATURDAY MORNING SHOULD BE SIMILAR TO THIS
MORNING. IN OTHER WORDS...WE CAN EXPECT LOW-END MVFR TO IFR CEILINGS
BETWEEN ROUGHLY 13Z AND 19Z. IT SHOULD RECEDE TO THE COAST AGAIN IN
THE AFTERNOON.

KSEA...NORTHWEST WINDS 5-10 KT...BECOMING NORTHEAST 4-8 KT AFTER
06Z. STRATUS WITH BKN-OVC CEILINGS 600-1400 FT LIKELY 13Z-19Z.
MCDONNAL

&&

.MARINE...HIGH PRESSURE WELL OFFSHORE AND LOW PRESSURE EAST OF THE
CASCADES WILL MAINTAIN ONSHORE FLOW THROUGH WEDNESDAY.

SMALL CRAFT ADVISORY WESTERLY WINDS ARE OCCURRING IN THE CENTRAL AND
EASTERN STRAIT OF JUAN DE FUCA THIS EVENING. AT 8 PM THEY WERE JUST
BELOW THE THRESHOLD FOR GALES...AND IT IS POSSIBLE THAT A GALE
WARNING WILL NEED TO BE ISSUED AT SOME POINT THIS EVENING. SMALL
CRAFT ADVISORY NORTHWEST WINDS WERE ALSO OCCURRING IN ADMIRALTY
INLET. THE WINDS WILL GRADUALLY EASE AFTER MIDNIGHT.

THE SAME PATTERN WILL REPEAT EACH DAY THROUGH WEDNESDAY. WINDS WILL
RISE DURING THE AFTERNOON...REACH THEIR DIURNAL PEAK DURING THE
EVENING HOURS...THEN EASE OVERNIGHT. SMALL CRAFT ADVISORY WESTERLIES
ARE LIKELY EACH DAY IN THE CENTRAL AND EASTERN STRAIT OF JUAN DE
FUCA...AND GALES ARE POSSIBLE AT LEAST SATURDAY EVENING. SMALL CRAFT
ADVISORY WINDS ARE ALSO LIKELY SOME DAYS OVER THE COASTAL WATERS AND
IN ADMIRALTY INLET.   MCDONNAL

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY THROUGH TONIGHT CENTRAL AND EASTERN STRAIT
     OF JUAN DE FUCA.
     SMALL CRAFT ADVISORY THIS EVENING ADMIRALTY INLET.

&&

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