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182
FXUS66 KEKA 231733
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
933 AM PST SUN NOV 23 2014

.SYNOPSIS...TODAY HIGH PRESSURE IS BUILDING INTO THE AREA AND
WILL BRING DRY CONDITIONS...ALTHOUGH AN APPROACHING WARM FRONT
WILL SPREAD CLOUDS ACROSS THE AREA. TONIGHT AND MONDAY THIS WEAK
WARM FRONT MAY BRING SOME LIGHT RAIN. HIGH PRESSURE AND DRY
CONDITIONS RETURN TUESDAY THROUGH THURSDAY. THURSDAY NIGHT THROUGH
THE WEEKEND THE WET PATTERN RETURNS.

&&

.UPDATE...CLOUDS CONTINUE TO SPREAD OVER THE REGION AS A WARM
FRONT DEVELOPS OFF THE COAST. MOST AREAS WILL REMAIN MOSTLY CLOUDY
TODAY INTO MONDAY. THE GFS AND NAM NOW BOTH INDICATE LIGHT RAIN
MOVING OVER THE REGION ON MONDAY...PRIMARILY NORTH OF CAPE
MENDOCINO. CHANCES FOR PRECIPITATION HAVE BEEN INCREASED 15-20
PERCENT FOR MONDAY AND MAY NEED TO BE INCREASED FURTHER IF THESE
TWO MODELS REMAIN CONSISTENT AND THE ECMWF COMES INTO ALIGNMENT AS
WELL. CLOUD COVER OFF THE COAST SEEMS TO CLOSELY MATCH THE NAM RH
FIELDS AT THIS TIME WHICH SUPPORTS LIGHT RAIN FOR TOMORROW.

OTHERWISE THE DRYING TREND IS STILL EXPECTED FOR TUESDAY THROUGH
THURSDAY AS AN UPPER LEVEL RIDGE BUILDS OVER THE WEST COAST. WET
CONDITIONS WILL RETURN FOR LATE IN THE WEEK INTO NEXT WEEKEND.
CHANCES FOR PRECIPITATION FOR NEXT WEEKEND WILL LIKELY NEED TO BE
INCREASED WITH THE AFTERNOON UPDATE TODAY.

THE PREVIOUS DISCUSSION IS INCLUDED BELOW. RPA

&&

.PREV DISCUSSION......ISSUED AT 335 AM PST...

DISCUSSION...A WEAK WARM FRONT IS BRINGING SOME HIGH CLOUDS TO
THE AREA THIS MORNING. OFFSHORE FLOW IS KEEPING THE IMMEDIATE
COAST MAINLY...BUT INLAND VALLEYS ARE SEEING SOME FOG AND LOW
CLOUDS THIS MORNING. THE HIGH CLOUDS WILL LIKELY PERSIST THROUGH
MUCH OF THE DAY...ALTHOUGH NO RAIN IS EXPECTED. THE INLAND VALLEYS
WILL LIKELY BE SLOW TO WARM UP WITH THE FOG AND LOW CLOUDS.
TONIGHT THIS WARM FRONT MOVES ONSHORE. MODELS ARE STRUGGLING WITH
THE TIMING AND LOCATION OF THE RAIN WITH THIS SYSTEM. THE NAM
BRINGS LIGHT RAIN IN FOR MUCH OF THE DAY AND COVERAGE IS FAIRLY
WIDESPREAD...WHILE THE GFS IS SLOWER. THE 00Z GFS WAS COMPLETELY
DRY...WHILE THE 06Z GFS HAS SOME LIGHT RAIN OR DRIZZLE MAINLY IN
THE AFTERNOON. AS THIS FEATURE IS RATHER SMALL SCALE SUSPECT THE
NAM MAY BE HANDLING IT BETTER THAN THE GFS. SO INCREASED CHANCES
FOR RAIN ON MONDAY AND IF MODELS REMAIN CONSISTENT THEY MAY NEED
TO BE INCREASED MORE. RAINFALL AMOUNTS WILL BE LIGHT...UP TO A
QUARTER INCH AT MOST.

MONDAY THROUGH WEDNESDAY HIGH PRESSURE CONTINUES TO BUILD IN AND
DRY THINGS OUT. THERE WILL LIKELY BE WIDESPREAD VALLEY FOG AND
CHILLY TEMPERATURES EACH MORNING WITH PLEASANT AFTERNOONS. SOME
FROST IN THE INTERIOR LOCATIONS IS POSSIBLE...ALTHOUGH THE FOG MAY
INHIBIT COOLING SO THIS WILL NEED TO BE WATCHED AS IT GETS CLOSER.

THE RIDGE STARTS TO BREAK DOWN ON THURSDAY...HOWEVER MODELS
DISAGREE ON THE STRENGTH OF THE FRONT THE BREAKING IT DOWN. THE
ECMWF AND GEM HAVE THE FRONT DYING JUST OFF THE COAST THURSDAY
AFTERNOON AND POSSIBLY BRINGING A FEW SPRINKLES TO THE
COAST...WHILE THE GFS BRINGS IT FARTHER ONSHORE. GENERALLY TRENDED
TOWARDS THE SLOWER SOLUTION DUE TO THE STRENGTH OF THE RIDGE IN
PLACE. FRIDAY THERE ARE STILL A LOT OF QUESTION MARKS ON WHERE THE
FRONT WILL BE...BUT INCREASED POPS SOME ALONG THE COAST AS THE
ECMWF AND GFS BOTH HAVE SOME RAIN IN THE AFTERNOON. FRIDAY NIGHT
THROUGH SUNDAY THERE IS GENERAL AGREEMENT THAT IT WILL BE A RATHER
WET PERIOD...HOWEVER THERE ARE SOME DIFFERENCES IN THE TIMING OF
THE FEATURES. MKK

AVIATION...VALLEY FOG AND POCKETS OF LOWER CLOUD COVER ALONG PARTS
OF THE COAST WILL ERODE LATE IN THE MORNING AND MAKE FOR BETTER
AVIATION CONDITIONS BY EARLY AFTERNOON. THE ONLY OBSTRUCTION
EXPECTED TODAY WILL BE HIGH, THIN CLOUD COVER STREAMING AHEAD OF AN
APPROACHING WARM FRONT. LIGHT RAIN WILL BE POSSIBLE WITH THE ARRIVAL
OF THE WARM FRONT BY LATE TONIGHT FOR AIRFIELDS NORTH OF CAPE
MENDOCINO. EXPECT ONLY SLIGHT CEILING REDUCTIONS WITH THE RAIN LATE
TONIGHT OTHERWISE VFR CONDITIONS SHALL PREVAIL TODAY. KML

MARINE...THE MARINE FORECAST REMAINS ON TRACK AS HIGH PRESSURE OVER
HEAD MAINTAINS A WEAKER PRESSURE GRADIENT THROUGH THE MIDDLE OF THE
FOLLOWING WEEK. THE SHIFTING RIDGE OF HIGH PRESSURE WILL CAUSE WIND
DIRECTION TO VARY ACROSS THE COASTAL WATERS AS IT PUSHES EASTWARD,
HOWEVER, EXPECT NORTHERLY WINDS TO INCREASE SOUTH OF CAPE MENDOCINO
OVER THE NEXT FEW DAYS. THIS WILL GENERATE GUSTIER CONDITIONS ACROSS
PARTS OF THE SOUTHERN WATERS ALONG WITH A LIGHT WIND CHOP.
FURTHERMORE, SEAS WILL BE ON THE DECLINE AS A NORTHWESTERLY WAVE
DIMINISHES ACROSS THE COASTAL WATERS THROUGH THE UPCOMING WEEK. THE
SMALL CRAFT ADVISORIES WERE EXTENDED TO 9 AM MONDAY MORNING. THERE
IS STILL SOME UNCERTAINTY ON HOW QUICKLY THEY WILL DROP BELOW
CRITERIA...BUT THEY SHOULD FALL BELOW CRITERIA LEVELS BY EARLY IN
THE AFTERNOON. A LOW PRESSURE SYSTEM WILL THEN APPROACH THE REGION
CAUSING SOUTHERLY WINDS TO INCREASE ACROSS THE COASTAL WATERS BY
WEDNESDAY/THURSDAY. MODELS STILL EXHIBIT SOME DIFFERENCES IN THE
STRENGTH AND TIMING OF THIS SYSTEM AND THUS THE UNCERTAINTY IN THE
MAGNITUDE OF THE WINDS CONTINUES. IF THE GFS PLAYS OUT THEN
ADVISORIES MAY BE WARRANTED LATE IN THE WEEK OTHERWISE WINDS MAY
REMAIN BELOW SMALL CRAFT CRITERIA. KML

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 9 AM PST MONDAY FOR
     PZZ450-455-470-475.

&&

$$

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