Hazardous Seas Warning 18, NWS Eureka, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1150 AM PDT TUE MAY 19 2009

.SYNOPSIS...A WEAK COOL FRONT WILL MOVE ACROSS NORTHERN CALIFORNIA
TODAY WITH COOLER TEMPERATURES ACROSS THE REGION. PATCHY FOG AND
DRIZZLE REDEVELOP ALONG THE COAST OVERNIGHT. WARMER AND DRIER
WEATHER RETURNS FOR THE LATTER HALF OF THE WEEK AS WEAK OFFSHORE
FLOW SETS UP.
&&

.UPDATE...GIVEN CURRENT SATELLITE TRENDS...ISSUED QUICK UPDATE TO
LOWER SKY COVER ALONG THE REDWOOD COAST THROUGH THIS EVENING.
OTHERWISE...CURRENT FCST ON TRACK.
&&

.PREV DISCUSSION...ISSUED AT 415 AM PDT TUE MAY 19 2009...AS AN
UPPER LEVEL LOW CRASHES ONTO THE PAC NW COAT THIS MORNING...A WEAK
COOL FRONT WILL SWEEP ACROSS NORTHERN CALIFORNIA. THIS FRONT IS
CURRENTLY STILL OFFSHORE...BUT SHOULD PUSH QUICKLY THROUGH THE AREA.
WITH COOL ONSHORE FLOW BEHIND THE FRONT...I DONT EXPECT MUCH
CLEARING ALONG THE COAST THIS AFTERNOON. FURTHER INLAND...THE
DISSIPATING FRONT MAY TRIGGER A FEW CUMULUS BUILD-UPS...BUT NO MORE
THAN A BRIEF PASSING SHOWER AT HIGHER ELEVATIONS IS EXPECTED.

AFTER THE COOLEST DAYTIME HIGHS THAT WE HAVE SEEN IN MORE THAN A
WEEK...TEMPERATURES WILL BEGIN TO REBOUND ON WEDNESDAY. HIGH
PRESSURE BUILDING IN BEHIND TODAYS TROUGH WILL PROMOTE A WEAK
OFFSHORE FLOW. THIS SEASONAL RETURN TO THE PATTERN OF HIGH PRESSURE
ALOFT WILL ALSO LEND ITSELF TO THE REESTABLISHING OF THE THERMALLY
INDUCED LOW OVER CALIFORNIA. THIS PATTERN WILL LEAD TO INCREASING
NORTHERLY WINDS OFFSHORE.

GLOBAL MODELS ARE HINTING AT INCREASING MOISTURE IN THE FOUR CORNERS
REGION LATE IN THE WEEK. THIS MOISTURE MAY SLOWLY MOVE NW TOWARD
CALIFORNIA BY THE WEEKEND...WHICH WOULD BRING AN INCREASING THREAT
OF MAINLY AFTERNOON/EVENING CONVECTION OVER HIGHER TERRAIN. JCA

&&

.AVIATION...A COLD FRONT PASSED OVER THE AREA THIS MORNING...WITH
WEAK ONSHORE FLOW IN PLACE IN ITS WAKE. LOW CLOUDS/DRIZZLE WILL
CONTINUE ALONG THE COAST THROUGH THE MORNING HOURS AS A RESULT. DOES
LOOK AS THOUGH MOST OF THE COAST WILL CLEAR OUT LATER THIS AFTERNOON
AS WEAK OFFSHORE FLOW SETS UP...QUESTION IS WHEN. ATTM...LOOK FOR
CRESCENT CITY TO GO VFR BETWEEN 00Z AND 03Z. KACV IS REALLY TRICKY
AS LATEST NAM12 GUIDANCE SUGGESTS A STRONG POSSIBILITY OF LOW CLOUDS
THROUGH 12Z TOMORROW. FOR NOW WILL GO WITH VFR CONDITIONS LATE THIS
AFTERNOON FOLLOWED BY A RETURN OF IFR IN THE EVENING. INLAND VALLEYS
NORTH OF THE CAPE WILL SEE LOW CLOUDS AND FOG EARLY...WITH CLEARING
EXPECTED THIS AFTERNOON. LIGHT LOW LEVEL TURBULENCE CAN BE EXPECTED
ALONG THE COAST STARTING THIS AFTERNOON AS THE LOW LEVEL WINDS PICK
UP IN RESPONSE TO BUILDING HIGH PRESSURE. BK

&&

.MARINE...HIGH PRESSURE IS BUILDING OVER THE PAC NW THIS
MORNING...AND AS A RESULT WINDS WILL BE PICKING UP OFF THE NRN CA
COAST. LATEST NAM12/GFS GUIDANCE SUGGESTS WINDS OVER THE SOUTHERN
WATERS WILL BUILD TO SCA CRITERIA LATER THIS MORNING/EARLY AFTERNOON
AND HAVE HOISTED A SCA FOR WINDS AND HAZ SEAS ACCORDINGLY. THE
NORTHERN WATERS WILL FOLLOW SUIT THIS EVENING AND HAVE ISSUED A SCA
FOR WINDS AND HAZ SEAS OVER THE NRN OUTER WATERS ACCORDINGLY. MODELS
REMAIN IN GOOD AGREEMENT WITH GALE/HAZ SEAS CONDITIONS DEVELOPING
WED MORNING AS THE SFC PRES GRADIENT CONTINUES TO TIGHTEN. MADE NO
CHANGE TO THIS FORECAST...WITH THE GALES/HAZ SEAS STARTING LATE WED
MORNING/EARLY AFTERNOON. THE PATTERN DOES NOT LOOK FOR MUCH CHANGE
THROUGH THE WEEKEND...ALTHOUGH THE HIGH PRESSURE OVER THE PAC DOES
LOOK TO WEAKEN ON SAT. WILL WAIT FOR ONE MORE MODEL PACKAGE TO COME
IN...BUT IT LOOKS LIKE THE GALE/HAZ SEAS CONDITIONS WILL BE MARGINAL
ALL THE WAY INTO SATURDAY.

SEAS WILL BE DOMINATED BY SHORT PERIOD FRESH SWELL/WIND WAVE THROUGH
THE PERIOD DUE TO THE STRONG NORTHERLY WINDS. BK

&&

.EKA WATCHES/WARNINGS/ADVISORIES...

PZZ470
SMALL CRAFT ADVISORY FOR WINDS AND HAZARDOUS SEAS IN EFFECT FROM
THIS EVENING THROUGH WEDNESDAY AFTERNOON.
GALE AND HAZARDOUS SEAS WATCH IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH LATE THURSDAY NIGHT.

PZZ455
SMALL CRAFT ADVISORY FOR WINDS AND HAZARDOUS SEAS IN EFFECT FROM 2
PM PDT THIS AFTERNOON THROUGH WEDNESDAY MORNING.

PZZ475
SMALL CRAFT ADVISORY FOR WINDS AND HAZARDOUS SEAS IN EFFECT FROM 11
AM PDT THIS MORNING THROUGH WEDNESDAY MORNING.
GALE AND HAZARDOUS SEAS WATCH IN EFFECT FROM WEDNESDAY MORNING
THROUGH LATE THURSDAY NIGHT.

&&

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