088
FXUS66 KEKA 151320
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
520 AM PST SUN DEC 15 2024
SYNOPSIS
CONDITIONS WILL BRIEFLY CALM AND DRY THIS MORNING BEFORE
ANOTHER WEAK SYSTEM TONIGHT BRING SLIGHT TO MODERATE RAIN AND GUSTY
SOUTH WINDS INTO MONDAY. DRIER AND CALMER WEATHER WILL THEN BUILD
THROUGH MIDWEEK.
DISCUSSION
THE FINAL DWINDLING SHOWERS EXITED THE AREA LATE
OVERNIGHT, BRINGING GENERALLY SCATTERED SKIES. COLD AIR ADVECTION
HAS WORKED TO RAPIDLY DRY OUT AND COOL SOME AREAS OVERNIGHT, BUT
ABUNDANT MOISTURE FROM RECENT RAINS HAS GENERALLY PROMOTED
WIDESPREAD VALLEY FOG, HELPING TO KEEP MOST OVERNIGHT LOWS ABOVE 40.
CALMER AND DRIER CONDITIONS WILL BE VERY SHORT LIVED THIS MORNING AS
YET ANOTHER UPPER LEVEL TROUGH AND COLD FRONT WILL BEGIN TO
INFLUENCE THE AREA AS SOON AS THIS EVENING. GUSTY SOUTHERLY WIND
WILL BE THE FIRST EFFECT OF THE SYSTEM. HIGH RESOLUTION MODELS ARE
SHOWING A JET AT 850 MB CROSSING THE AREA AROUND MIDNIGHT WITH
SPEEDS OF 55 TO 65 KTS. NBM IS GENERALLY SHOWING A 60 TO 80% CHANCE
OF GUSTS TO AT LEAST 50 MPH AT HIGH RIDGETOPS, WITH SIMILAR CHANCES
OF GUSTS UP TO 45 MPH ON EXPOSED COASTAL HEADLANDS. THE EFFICIENCY
OF MIXING WILL BE THE BIGGEST QUESTION. WILL CONFIDENCE IS HIGH OF
STRONG GUSTS AT HIGH ELEVATIONS, MODEL SOUNDINGS APPEAR MOST STABLE
FOR LOW ELEVATIONS, WHICH WILL LIMIT THE STRONGEST GUSTS.
UNCERTAINTY IS HIGH. THAT SAID, THE ABSOLUTE HIGH END OF GUSTS WOULD
BE NO MORE THAN AROUND 55 MPH AT LOW ELEVATIONS, WITH MOST LIKELY
GUSTS CLOSER TO 35 TO 45 MPH.
PRECIPITATION WILL QUICKLY BUILD BEHIND THE SURFACE COLD FRONT EARLY
MONDAY MORNING. MOST LIKELY RAINFALL WILL BE 0.5 INCHES AT LOW
ELEVATIONS ALONG THE COAST WITH 1.0 TO 1.5 INCHES AT HIGHER
ELEVATIONS IN WIND FAVORED TERRAIN RAIN AMOUNTS WILL GENERALLY BE
MORE SUBDUED FOR THE MENDOCINO AND LAKE COUNTY WITH AMOUNTS BELOW
0.5 INCHES. SOME MINOR EVAPORATIVE COOLING COMBINED WITH STRONG
UPSLOPE COOLING WILL ONCE AGAIN HELP LOWER SNOW LEVELS TO NEAR 3000
FEET IN TRINITY COUNTY, ESPECIALLY WITH THE STRONGEST SNOWFALL
OCCURRING OVERNIGHT. THIS WILL MOST LIKELY AID IN 2 TO 6 INCHES OF
SNOW FALLING AROUND TRINITY LAKE, AND SECTIONS OF HIGHWAY 299, 3,
AND 36 IN THE EASTERN PARTS OF THE COUNTY. GENERALLY WEAK MOISTURE
TRANSPORT WILL LIMIT THE MAXIMUM OVERALL SNOWFALL.
SHOWERS WILL GRADUALLY DISSIPATE THROUGH THE DAY ON MONDAY WITH VERY
LITTLE CHANCE (LESS THAN 10%) OF EVEN ISOLATED THUNDER. THERE IS
HIGH MODEL CONFIDENCE THAT AN UPPER LEVEL RIDGE AND HIGH PRESSURE
WILL BUILD THROUGH MIDWEEK, HELPING TO GENERALLY BRING DRY AND CALM
WEATHER WITH DAYTIME HIGHS RETURNING TO THE 60S. OFFSHORE FLOW MAY
ALSO HELP PROMOTE COOL OVERNIGHT LOWS DROPPING BACK INTO THE 30S
EVEN FOR THE COAST, BUT THOSE EXACT LOW WILL GREATLY DEPEND ON CLOUD
COVER AND DEWPOINT TRENDS EACH NIGHT. THERE IS HIGH MODEL CONFIDENCE
THAT ANOTHER MODERATE ATMOSPHERIC RIVER WILL IMPACT THE AREA THIS
WEEKEND. LONG RANGE MODELS SHOW HIGH CHANCES OF A SERIES OF SYSTEMS
(60 TO 80% CHANCE) CONTINUING TO IMPACT THE AREA THROUGH CHRISTMAS.
/JHW
AVIATION
VFR CONDITIONS ARE PRESENT ALONG THE COAST WITH SOME
SHALLOW INLAND FOG SURROUNDING KUKI THIS MORNING. THIS FOG IS
EXPECTED TO EVAPORATE AWAY SHORTLY AFTER SUNRISE. WINDS ARE
FORECASTED TO PICK UP TODAY BRINGING GUSTS AND WINDSHEAR WITH WINDS
AT 2KFT AGL UP TO 50KTS OVER COASTAL ZONES. RAIN AND SLIGHTLY
DEGRADED CONDITIONS (MVFR) ARE FORECASTED, YET BRIEF PERIODS OF IFR
ARE POSSIBLE DURING PASSING OVERHEAD SHOWERS THIS EVENING INTO EARLY
TOMORROW MORNING.
MARINE
A LARGE MID-PERIOD NW SWELL CONTINUES TO DOMINATE THE
WATERS. THE SEA STATE WILL CONTINUE TO BE CHAOTIC AND HAZARDOUS INTO
THE COMING WORK WEEK. SOUTHERLY WINDS ARE EXPECTED TO BUILD STEADILY
THROUGH THE DAY AS ANOTHER ROUND OF GALE FORCE SOUTHERLY WINDS ARE
EXPECTED ACROSS ALL WATERS THIS EVENING INTO MONDAY. LOCALIZED AREAS
OF STORM FORCE WINDS ARE POSSIBLE WITH WITH THE STRONGEST WIND GUSTS
FORECASTED TO REACH 50 KTS IN THE OUTER WATERS. A LARGE WESTERLY
SWELL AROUND 17-19 FEET IS EXPECTED TO MOVE ACROSS THE WATERS LATE
MONDAY NIGHT THROUGH TUESDAY AFTERNOON.
BEACH HAZARDS
A SERIES OF LARGE, MID-LONG PERIOD, WESTERLY SWELLS
WILL CONTINUE TO IMPACT THE COASTAL WATERS OF NORTHWEST CALIFORNIA
DURING NEXT WEEK. THE CURRENT 12-15 SWELL WILL CONTINUE TO SUBSIDE
EVER SO SLIGHTLY THROUGH THE DAY. GFS WAVE MODEL SUGGEST THERE IS
ANOTHER LARGE SWELL AROUND 16 TO 18 FEET BUILDING ACROSS THE WATER
LATE MONDAY NIGHT THROUGH TUESDAY AFTERNOON. THIS IS EXPECTED TO
BRING BREAKERS BETWEEN 20 TO 22 FEET ALL DAY TUESDAY. HAZARDOUS SURF
CONDITIONS DUE TO THE BREAKING WAVES TUESDAY WILL BE POSSIBLE ALONG
WEST-NORTHWEST FACING BEACHES. -ZVS
COASTAL FLOODING
HIGH ASTRONOMICAL TIDES ARE PREDICTED TO
CONTINUE THROUGH EARLY NEXT WEEK FOR NORTHWEST CALIFORNIA. HIGH
TIDES ARE FORECAST TO BE AT 8.55 FEET AT THE NORTH SPIT TIDE GAUGE
AT AROUND 10:42 AM ON SUNDAY. HIGH TIDES COMBINED WITH SURGE AND
TIDAL ANOMALY WILL RESULT IN WATER LEVELS BETWEEN 9.0 TO 9.3 FEET.
MINOR COASTAL FLOODING AROUND HUMBOLDT BAY, INCLUDING KING SALMON
AND JACKSON RANCH ROAD IN THE ARCATA BOTTOMS, WILL BE LIKELY BETWEEN
10AM AND NOON. A COASTAL FLOODING ADVISORY WILL BE IN EFFECT FROM
9AM TO 1PM SUNDAY. -ZVS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
WIND ADVISORY FROM 10 PM THIS EVENING TO 7 AM PST MONDAY
FOR CAZ101.
WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM PST MONDAY
FOR CAZ102-104>106.
COASTAL FLOOD ADVISORY FROM 9 AM THIS MORNING TO 1 PM PST
THIS AFTERNOON FOR CAZ103.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 PM
PST MONDAY FOR CAZ107-108.
COLD WEATHER ADVISORY UNTIL 8 AM PST THIS MORNING FOR
CAZ109-112-113-115.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 PM PST THIS EVENING FOR PZZ450-
455-475.
GALE WARNING FROM 9 PM THIS EVENING TO 9 AM PST MONDAY FOR
PZZ450-455-475.
SMALL CRAFT ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR
PZZ470.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 9 AM PST MONDAY
FOR PZZ470.
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