Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 062348
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
448 PM PDT WED MAY 6 2015

.SYNOPSIS...AN UPPER TROUGH WILL SLOWLY SINK SOUTH OVER
CALIFORNIA THIS WEEK HOWEVER CONDITIONS WILL REMAIN MOSTLY DRY
WITH ONLY A FEW ISOLATED SHOWERS OVER THE INTERIOR MOUNTAINS. GUSTY
WINDS WILL CONTINUE ALONG THE COAST AND ON EXPOSED RIDGES THROUGH
FRIDAY MORNING. TEMPERATURES SHOULD CONTINUE TO BE SEASONAL OVER
THE NEXT FEW DAYS.

&&

.UPDATE...WINDS CONTINUE TO INCREASE LATE THIS AFTERNOON ALONG THE
IMMEDIATE COAST. THIS IS ESPECIALLY TRUE OF CRESCENT CITY WHERE
WINDS ARE GUSTING INTO THE LOW 40 MPH RANGE. WINDS ARE EXPECTED TO
INCREASE A TOUCH MORE THIS AFTERNOON AND EARLY EVENING DUE TO A
LOW LEVEL COASTAL JET SETTING UP BETWEEN STOUT HIGH PRESSURE OVER
THE EASTERN PACIFIC AND WEAK FRONT DEPARTING THE REGION TO THE SE.
AS SUCH, HAVE ISSUED A WIND ADVISORY FOR CRESCENT CITY AND COASTAL
AREAS OF DEL NORTE COUNTY. WINDS WILL NOT BE AS STRONG ACROSS
HUMBOLDT OR MENDOCINO COASTAL AREAS.

THE OTHER UPDATE WAS TO ADD ISOLATED SHOWERS TO EASTERN TRINITY
COUNTY AND FAR NE MENDOCINO COUNTY. RADAR HAS BEEN SHOWING SOME
DECENT RETURNS THE LAST HOUR, WHILE VISIBLE SATELLITE CONTINUES TO
SHOW CLOUDS DEVELOPING. PARAMETERS DO NOT LOOK GOOD FOR
THUNDERSTORM DEVELOPMENT, SO HAVE LEFT THEM OUT FOR THIS
AFTERNOON, BUT MODELS HAVE BEEN WRONG IN THE PAST. IF OUT NEAR
THESE SHOWERS, WATCH THE VERTICAL DEVELOPMENT, AS THERE MAY BE ONE
OR TWO THAT BLOW THROUGH THE CAP AND GENERATE A LIGHTNING STRIKE
OR TWO. CONFIDENCE IS LOW IN THIS OCCURRING, HENCE NO TSTMS IN THE
FORECAST. BFG

&&

.PREV DISCUSSION......ISSUED AT 343 PM PDT...

SYNOPSIS...AN UPPER TROUGH WILL SLOWLY SINK SOUTH OVER
CALIFORNIA THIS WEEK HOWEVER CONDITIONS WILL REMAIN MOSTLY DRY
WITH ONLY A FEW ISOLATED SHOWERS OVER THE INTERIOR MOUNTAINS. GUSTY
WINDS WILL CONTINUE ALONG THE COAST AND ON EXPOSED RIDGES THROUGH
FRIDAY MORNING. TEMPERATURES SHOULD CONTINUE TO BE SEASONAL OVER
THE NEXT FEW DAYS.

DISCUSSION...GUSTY CONDITIONS HAVE CONTINUED THROUGH THE DAY
TODAY AS A SLOW MOVING UPPER TROUGH SLIDES DOWN THE WEST
COAST...IN PARTICULAR RIGHT ALONG THE COAST AND ALONG EXPOSED
RIDGES. THESE GUSTY WINDS ARE LIKELY TO CONTINUE THROUGH FRIDAY
MORNING...BUT WILL GRADUALLY WEAKEN AS RIDGING BUILDS IN ALOFT AND
THE SURFACE PRESSURE GRADIENT WEAKENS OVER THE WEEKEND.
TEMPERATURES OVERNIGHT TONIGHT WILL ONCE AGAIN BE CHILLY...HOWEVER
MUCH LIKE LAST NIGHT GUSTY NE WINDS WILL LIKELY INHIBIT
RADIATIONAL COOLING IN EXPOSED AREAS. OPTED TO ISSUE ANOTHER FROST
ADVISORY FOR THE UPPER TRINITY ZONE AS CONFIDENCE IS HIGHEST
HERE...HOWEVER PROTECTED POCKETS IN THE MENDOCINO AND NORTH COAST
INTERIOR ZONES MAY ALSO SEE SOME FROST AS WELL. AS FOR RAIN
CHANCES THIS AFTERNOON...A FEW CUMULUS CLOUDS HAVE DEVELOPED
ACROSS THE INTERIOR MOUNTAINS...AND WHILE A FEW SPRINKLES AND EVEN
A FEW SNOWFLAKES ARE POSSIBLE ALONG THE HIGHEST PEAKS WITH THIS
ACTIVITY AS IT MATURES...VERY LOW MOISTURE WILL PREVENT ANY
MEANINGFUL RAINFALL FROM FALLING. BETTER CHANCES FOR SHOWERS WILL
OCCUR TOMORROW ACROSS THE INTERIOR HIGH TERRAIN...AS MODEST MID
LEVEL MOISTURE WILL MOVE INTO THE AREA AROUND THE BACK SIDE OF THE
DEPARTING UPPER LOW. WILL CONTINUE TO LEAVE OUT THUNDER MENTION AS
INSTABILITY APPEARS TO BE MEAGER EVEN WITH THE INCREASING MOISTURE
AND COOLING TEMPERATURES ALOFT...HOWEVER A FEW STRIKES OF
LIGHTNING WILL NOT BE COMPLETELY OUT OF THE QUESTION AND THIS WILL
HAVE TO BE MONITORED.

SHOWER CHANCES WILL CONTINUALLY DECREASE THROUGH SATURDAY AS
TRANSIENT UPPER RIDGING BUILDS IN ALOFT. TEMPERATURES OVER THE
WEEKEND WILL INCREASE ACROSS THE INTERIOR...WITH HIGHS REACHING
BACK INTO THE UPPER 70S AND LOW 80S ACROSS INTERIOR VALLEYS. BY
SUNDAY...MODELS CONTINUE TO INDICATE THAT ANOTHER CUTOFF LOW WILL
BEGIN TO IMPACT THE CALIFORNIA COAST...HOWEVER SIGNIFICANT
DIFFERENCES IN TIMING AND STRENGTH PERSIST DESPITE SLIGHTLY BETTER
AGREEMENT IN RECENT RUNS. IN ANY CASE...SHOWER ACTIVITY WILL
LIKELY INCREASE ACROSS AT LEAST THE INTERIOR FROM SUNDAY AFTERNOON
THROUGH EARLY NEXT WEEK.

AVIATION...SOME STRATUS OVER THE COASTAL RIDGES THIS MORNING HAS
GIVEN WAY TO VFR ACROSS THE AREA THIS AFTERNOON WITH SOME CU BUILD-
UPS OVER THE INTERIOR MOUNTAINS. HIGH PRESSURE BUILDING OVER THE E
PAC INTERACTING WITH AN AREA OF LOW PRESSURE DROPPING THROUGH THE
INTERIOR WEST HAS TIGHTENED THE PRESSURE GRADIENT CAUSING GUSTY
NORTHERLY WINDS ACROSS THE AREA. WINDS WILL DIMINISH LATER THIS
EVENING...ALTHOUGH WINDS VC KCEC WILL CONTINUE TO BE GUSTY
OVERNIGHT. GOING INTO THE OVERNIGHT...MAINLY VFR CAN BE EXPECTED
ACROSS NW CALIFORNIA AS DRY NORTHERLY FLOW PROMOTES GOOD MIXING.
SOME MVFR CIGS ARE POSSIBLE VC HUMBOLDT BAY AND THE EEL RIVER
VALLEY.

MARINE...NORTHERLY WINDS AND STEEP SEAS HAVE INCREASED ACROSS THE
WATERS AS HIGH PRESSURE BUILDING OVER THE E PAC INTERACTING WITH AN
AREA OF LOW PRESSURE DROPPING THROUGH THE INTERIOR WEST HAS
TIGHTENED THE PRESSURE GRADIENT. AS OF 21Z...SEAS OF 8 TO 12 FT WERE
REPORTED AT THE NEAR SHORE BUOYS WITH PERIODS AROUND 8 SECONDS.
WINDS AND SEAS WILL PEAK THIS EVENING AND AGAIN THURSDAY EVENING DUE
TO DIURNAL FLUCTUATIONS...BEFORE DIMINISHING FRIDAY INTO THE
WEEKEND. WENT AHEAD AND HOISTED A GALE WARNING FOR THE SOUTHERN
INNER WATERS THROUGH THURSDAY EVENING. WINDS WILL DECREASE A BIT
OVERNIGHT...BUT INCREASE AGAIN ON THURSDAY WITH THE HIGHEST WINDS
AND SEAS NEAR PT ARENA. ALSO HOISTED A GALE WARNING FOR THE NORTHERN
OUTER WATERS STARTING THURSDAY MORNING AND GOING THROUGH LATE
THURSDAY NIGHT...WHERE WINDS TO 40 KT ARE POSSIBLE. GALE WARNING
REMAINS IN EFFECT FOR THE SOUTHERN OUTER WATERS WITH A SMALL CRAFT
ADVISORY FOR THE NORTHERN INNER WATERS.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     WIND ADVISORY UNTIL 9 PM PDT THIS EVENING FOR CAZ001.

     FROST ADVISORY FROM 2 AM TO 8 AM PDT THURSDAY FOR CAZ004.

NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PZZ450.

     SMALL CRAFT ADVISORY UNTIL 9 AM PDT THURSDAY FOR PZZ470.

     GALE WARNING FROM 9 AM THURSDAY TO 3 AM PDT FRIDAY FOR PZZ470.

     GALE WARNING UNTIL 3 AM PDT FRIDAY FOR PZZ475.

     GALE WARNING UNTIL 9 PM PDT THURSDAY FOR PZZ455.

&&

$$

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