Current Version                Previous Version:  1  2  3  4  5  

AREA FORECAST DISCUSSION

 
 FXUS66 KEKA 251039
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
339 AM PDT WED MAR 25 2015

.SYNOPSIS...A RIDGE WILL CONTINUE TO BUILD OVER NORTHWEST
CALIFORNIA TODAY BRINGING WARMER AND DRIER WEATHER CONDITIONS
THROUGH FRI. A WEAK UPPER TROUGH WILL APPROACH ON FRI AND MAY
PRODUCE ISOLATED SHOWERS THIS WEEKEND.


&&

.DISCUSSION...UPPER LEVEL RIDGING IS BUILDING OVER THE WEST COAST
ALLOWING MOST MID AND HIGH LEVEL CLOUDS TO MOVE OUT OF THE REGION.
SOME THIN HIGH LEVEL CIRRUS WILL BE POSSIBLE THROUGH THE DAY BUT IN
GENERAL SUNNY SKIES ARE EXPECTED TODAY ACROSS THE INTERIOR ONCE
LINGERING LOW CLOUDS DISSIPATE THIS MORNING. BOUNDARY LAYER
MOISTURE PROFILES INDICATE THAT LOW CLOUDS MIGHT BE A BIT MORE
PERSISTENT TODAY THAN ORIGINALLY THOUGHT ALONG THE MENDOCINO
COAST. THUS SKY COVER HAS BEEN INCREASED WITH THIS FORECAST
UPDATE. LIGHT OFFSHORE FLOW MAY ALLOW THE HUMBOLDT AND DEL NORTE
COASTS TO REMAIN MOSTLY CLEAR TODAY.

LATER TONIGHT ALL MODEL GUIDANCE INDICATE STRATUS WILL RETURN ALONG
THE MAJORITY OF THE COASTLINE WHILE AT THE SAME TIME RADIATIONAL
COOLING RESULTS IN FOG DEVELOPING IN INTERIOR VALLEYS. THUS MANY
AREAS WILL SEE SOME VISIBILITY RESTRICTIONS TONIGHT/EARLY THURSDAY
MORNING. WITH A BUILDING RIDGE OVER NORTHWEST CALIFORNIA...STRATUS
MAY BECOME COMPACTED AND STUCK ON THE IMMEDIATE COAST. HAVE OPTED TO
CONTINUE THE POTENTIAL FOR PARTLY CLOUDY CONDITIONS IN THE AFTERNOON
ALONG THE COAST WITH THE STRATUS PULLING BACK TO THE BEACH FOR NOW.
THE STRATUS/FOG WILL PUSH BACK INLAND THURSDAY NIGHT.

WITH THE RIDGE OVER THE REGION...INTERIOR AREAS WILL WARM UP WELL
ABOVE NORMAL WITH TEMPERATURES PUSHING INTO THE UPPER 70S AND LOWER
80S THURSDAY AND FRIDAY.

A WEAKENING UPPER LEVEL WAVE WILL APPROACH THE COAST FRIDAY INTO
SATURDAY ALLOWING THE MARINE LAYER TO DEEPEN REDUCING THE CHANCE FOR
COASTAL FOG BUT ALSO ALLOWING THE CLOUDS TO EXPAND INTO COASTAL
VALLEYS AND BECOME POSSIBLY MORE PERSISTENT ALONG THE COAST. THUS
MOSTLY CLOUDY SKIES ARE EXPECTED FRIDAY INTO SATURDAY FOR COASTAL
AREAS. THE INTERIOR MAY DESTABILIZE ENOUGH FRIDAY AFTERNOON
THROUGH SATURDAY AFTERNOON ALLOWING A FEW MOUNTAIN SHOWERS OR
POSSIBLY A THUNDERSTORM TO DEVELOP. MODEL DISCREPANCIES IN THE
TIMING AND STRENGTH OF THIS SYSTEM DO NOT ALLOW FOR MORE THAN
SLIGHT CHANCE TO CHANCE POTENTIAL FOR RAIN. AND YES...IT WILL BE
MOSTLY RAIN WITH SNOW LEVELS RISING ABOVE 8000 FEET.

DRY CONDITIONS WILL RETURN FOR SUNDAY FOLLOWED BY ANOTHER WEAK UPPER
LEVEL WAVE ON MONDAY INTO TUESDAY. THIS SYSTEM HAS THE POTENTIAL TO
BRING SOME LIGHT SHOWERS TO THE REGION BUT ONCE AGAIN TIMING
UNCERTAINTIES AND MODEL SYSTEM STRENGTH DIFFERENCES DO NOT ALLOW FOR
ANY MORE THAN SLIGHT CHANCES FOR PRECIPITATION. /RPA


&&

.AVIATION...TAF SITES ARE REPORTING MOSTLY VFR THIS MORNING. EXPECT
VFR TO PREVAIL TODAY AS SURFACE HIGH PRESSURE BUILDS TOWARDS THE
WEST COAST.


&&

.MARINE...THE MORNING BUOY OBSERVATIONS ARE GENERALLY REPORTING A
LIGHT TO MODERATE BREEZE AND SEAS AROUND 7-8 FT. THE 436Z ASCAT PASS
SHOWED WINDS RANGING FROM CALM TO ABOUT 10 KT ACROSS OUR WATERS,
WHICH WAS WITHIN ABOUT 5 KT OF THE FORECAST. MODELS ARE IN GOOD
AGREEMENT SHOWING SURFACE HIGH PRESSURE BUILDING OFFSHORE THIS WEEK.
THIS WILL LEAD TO INCREASING NORTHERLY WINDS AND BUILDING SHORT-
PERIOD SEAS TODAY, CONTINUING INTO THE WEEKEND. THIS WILL BE IN
ADDITION TO THE ONGOING WESTERLY SWELL, WHICH WILL CONTINUE FOR THE
NEXT WEEK. THE PRESSURE GRADIENT WILL BE SLIGHTLY STRONGER SOUTH OF
CAPE MENDOCINO, MEANING WINDS WILL BE A LITTLE STRONGER THERE.
OCCASIONAL GUSTS UP TO 25 KT ARE EXPECTED ACROSS ZONE 475 TONIGHT,
BUT THIS WON`T BE ENOUGH TO WARRANT ANY HEADLINES. OTHERWISE,
NORTHERLY WINDS UNDER 20 KT AND SHORT-PERIOD SEAS WILL CONTINUE
THURSDAY AND FRIDAY. FRIDAY NIGHT INTO SATURDAY MORNING A WEAK FRONT
WILL PASS TO OUR NORTH. THIS COMBINED WITH THE SURFACE HIGH OFFSHORE
WILL INCREASE THE PRESSURE GRADIENT, CAUSING THE NORTHERLY WINDS TO
STRENGTHEN. HOW STRONG IS STILL QUESTIONABLE DUE TO DIFFERENCES IN
THE MODELS. BUT SOME HEADLINES WILL PROBABLY BE NEEDED, AT LEAST FOR
THE OUTER WATERS. THE REST OF SATURDAY INTO NEXT WEEK THE SURFACE
HIGH BUILDS BACK TOWARDS THE COAST, CONTINUING THE NORTHERLY WINDS
AND SHORT-PERIOD SEAS.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&




VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA

FOLLOW US ON FACEBOOK AND TWITTER AT:
HTTP://WWW.FACEBOOK.COM/NWSEUREKA
HTTP://WWW.TWITTER.COM/NWSEUREKA