110
FXUS66 KEKA 161320
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
520 AM PST MON DEC 16 2024
SYNOPSIS
LIGHT TO MODERATE RAIN AND GUSTY SOUTH WIND WILL
CONTINUE THROUGH THE MORNING AND DISSIPATE THROUGH THE EVENING.
CALMER AND DRIER WEATHER WILL BUILD THROUGH MIDWEEK BEFORE ANOTHER
ATMOSPHERIC RIVER SYSTEM THIS WEEKEND.
DISCUSSION
A MODERATE COLD FRONT HAS BEEN CROSSING THE AREA
OVERNIGHT, BRINGING WIDESPREAD RAIN AND GUSTY SOUTH WIND. HIE
ELEVATIONS OF HAVE SEEN PEAK GUSTS OF 40 TO 55 MPH ALONG THE NORTH
COAST. VERY STABLE AIR AT THE SURFACE HAS RESTRICTED LOW ELEVATION
GUSTS TO ONLY 35 TO 45 MPH EVEN ON EXPOSED HEADLANDS. OVERALL
RAINFALL HAS BEEN STEADY WITH 0.4 TO 0.8 INCHES ACROSS THE NORTHERN
HALF OF THE AREA. RAIN IS LIGHTER FOR THE SOUTHERN HALF OF THE AREA
WITH CLOSER TO 0.2 INCHES IN MENDOCINO AND DEL NORTE. INCONSISTENT
SNOW HAS FALLEN AS LOW AS 3000 FEET IN TRINITY COUNTY WITH CHAIN
RESTRICTIONS CURRENTLY IN PLACE ALL ALONG HIGHWAY 3 AND THE EASTERN
SECTIONS OF HIGHWAY 36.
RAIN AND GUSTY WIND WILL CONTINUE THROUGH THE DAY. AN ADDITIONAL 0.2
TO 0.4 INCHES IS MOST LIKELY ALONG THE NORTH COAST WITH EVEN LESSER
AMOUNTS FURTHER SOUTH AND EAST. SNOW WILL CONTINUE TO FALL ABOVE
3000 FEET IN TRINITY WITH ADDITIONAL LIGHT ACCUMULATION OF 1 TO 3
INCHES. GUSTS UP TO 45 MPH IN EXPOSED AREAS WILL REMAIN POSSIBLE,
ESPECIALLY AROUND MID DAY IN HUMBOLDT AND DEL NORTE. HIGHER
RESOLUTION MODELS ARE PUTTING A SECONDARY FRONTAL PASSAGE AROUND 10
AM WHICH COULD AGAIN INCREASE WINDS BEFORE THEY MORE CONSISTENTLY
CALM THIS EVENING.
UPPER LEVEL RIDGING WILL BUILD IN FOR THE MIDDLE OF THE WEEK,
PROMOTING CALMER, WARMER, AND DRIER CONDITIONS. BY WEDNESDAY,
INTERIOR HIGHS WILL MOST LIKELY WARM TO NEAR 60, THOUGH NEAR WINTER
SOLSTICE SUNLIGHT WILL KEEP WARMTH VERY SHORT LIVED. THOUGH HIGH
ELEVATIONS WILL DRY OUT UNDER THE INFLUENCE OF OFFSHORE FLOW, MOST
MODELS ARE INDICATING MORE SUSTAINED MARINE INFLUENCE AND MOISTURE
BOTH ALONG SHORE AND FOR INTERIOR VALLEYS. ABUNDANT VALLEY FOG WILL
MOST LIKELY FORM EACH MORNING (ESPECIALLY TUESDAY MORNING) HELPING
TO KEEP CONDITIONS RELATIVELY WARM OVERNIGHT.
THERE CONTINUES TO BE HIGH ENSEMBLE CONFIDENCE IN A STRONGER STORM
SYSTEM THIS WEEKEND, THOUGH THE ENSEMBLE MEAN HAS BOTH SHIFTED
SLIGHTLY LATER INTO THE WEEKEND AND FURTHER SOUTH. SPECIFICS REMAIN
HIGHLY VARIABLE, BUT MODELS ARE CURRENTLY RESOLVING TWO PULSES OF
MOISTURE OVER THE WEEKEND. MOST LIKELY 48 RAINFALL AMOUNTS CURRENTLY
RANGE FROM 2 TO 7 INCHES DEPENDING ON ELEVATION WITH THE HIGHEST
AMOUNTS FOCUSED IN NORTHERN MENDOCINO. ANOTHER ROUND OF GUSTY
SOUTHERLY WIND WILL BUILD AHEAD OF AND DURING THE SYSTEM, BUT VERY
HIGH WINDS DO NOT CURRENTLY APPEAR LIKELY WITH VERY LITTLE UPPER
LEVEL SUPPORT. NBM IS CURRENTLY ONLY PLACING A 30 TO 50% CHANCE OF
GUSTS OVER 50 MPH EVEN ALONG HIGH TERRAIN. ANY SNOWFALL WILL MOST
LIKELY BE VERY ISOLATED. WITH SUCH WIND SPEEDS, UPSLOPE COOLING WILL
BE MODEST AT BEST AND ALL MODELS ARE CURRENTLY SHOWING ONLY A VERY
NARROW AND TRANSIENT TROUGH OF COLD AIR ALOFT. SUCH A SETUP WILL BE
CONDUCIVE TO SNOW LEVELS ABOVE 4000 FEET OR EVEN HIGHER, GREATLY
LIMIT HIGHWAY PASS IMPACTS. OVERALL WET AND UNSETTLED WEATHER IS
MOST LIKELY TO CONTINUE THROUGH CHRISTMAS. /JHW
AVIATION
BIGGEST PROBLEM WILL BE CONCERNING LOW-LEVEL WIND SHEAR
THIS MORNING, POSSIBLY HEADING INTO THE AFTERNOON. DESPITE GUSTY
WINDS AT THE SURFACE ALONG THE COAST, WINDS ALOFT NEAR 1500-2000 FT
WILL BE JUST STRONG ENOUGH TO INCLUDE LLWS. KUKI MAY HAVE A BIT
EASIER TIME OF REACHING LLWS CRITERIA AS THE LOW-LEVEL JET AXIS
SHIFTS SOUTHEAST. WINDS AT THE COASTAL SITES WILL DECREASE IN SPEED
THIS MORNING, BUT A SECONDARY PEAK FOR THE COASTAL SITES WILL OCCUR
AROUND 21Z ACCORDING TO NBM. SURFACE WINDS AT KUKI SHOULD DROP OFF
AFTER 21Z. SOMETHING NOTABLE WILL BE THAT THE PROBABILITY OF LOWER
CEILINGS WILL BE GENERALLY AT THE GREATEST ALONG THE COAST AT NEAR
20Z, WITH A SOLID 60-80% CHANCE OF CEILINGS UNDER 3 KT FEET,
ALTHOUGH KACV WILL AGAIN BE AROUND 60% CHANCE BY 09Z TUESDAY.
CHANCES FOR VISIBILITY LESS THAN 5SM INCREASE TO AROUND 60-70%
GENERALLY BETWEEN 19Z AND 02Z ALONG THE COAST, AND 60-70% CHANCE
BETWEEN 14Z AND 19Z AT UKI. MOST RAIN WILL BE DIMINISHING BY AROUND
04Z THIS EVENING, EXCEPT KCEC WHERE IT MAY LINGER THROUGH MUCH OF
THE NIGHT AND INTO EARLY TUESDAY MORNING WITH LIGHT SHOWERS
POTENTIALLY LINGERING. /MH
MARINE
BIGGEST PROBLEM WILL BE WHAT TO DO AFTER THE GALE WARNING
EXPIRES THIS MORNING AT 9AM AS WINDS SUBSIDE BEHIND A PASSING COLD
FRONT. ALTHOUGH WIND SPEEDS CONTINUE TO DECREASE INTO THE 00Z TO 06Z
RANGE THIS EVENING, AT LEAST A THIRD OF THE NORTHERN OUTER WATERS
STAND A BETTER THAN 50% CHANCE OF FREQUENT 22KT GUSTS AT THIS
RELATIVELY LOWER WIND SPEED WINDOW (WIND STILL FROM THE SOUTH),
BEFORE GENERALLY INCREASING AGAIN BY OVERNIGHT TONIGHT. THE
COMBINATION OF STEEP SEAS AND WINDS NEAR SMALL CRAFT CRITERIA SHOULD
NEARLY GUARANTEE A REPLACEMENT OF THE GALE WARNING WITH A SMALL
CRAFT ADVISORY THIS MORNING FOR AT LEAST THE NORTHERN OUTER WATERS
IF NOT A CHUNK OF THE REST OF THE WATERS. IT MIGHT BE TRICKY
DETERMINING HOW LONG TO GO WITH ANY SMALL CRAFT ADVISORY (ESPECIALLY
OVER NORTHERN OUTER WATERS) AS ANOTHER SWELL BUILD IN TONIGHT,
PRODUCING MORE STEEP WAVES, ESPECIALLY OVER THE NORTHERN OUTER
WATERS. THE COMBINATION OF STRONGER WINDS AND STEEP WAVES COULD KEEP
SMALL CRAFT ADVISORY CONDITIONS FOR NORTHERN OUTER WATERS WILL INTO
WEDNESDAY WHEN YET YET ANOTHER SWELL BUILDS IN AND PRESENTS MORE
POTENTIALLY STEEP WAVES BUILDING IN. /MH
COASTAL FLOODING
HIGH ASTRONOMICAL TIDES ARE PREDICTED TO
CONTINUE ON MONDAY. HIGH TIDES ARE FORECAST TO BE AT 8.33 FEET AT
THE NORTH SPIT TIDE GAUGE AT AROUND 11:28 AM LOCAL TIME. HIGH TIDES
COMBINE WITH STORM 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 1PM. A COASTAL
FLOODING ADVISORY WILL BE IN EFFECT FROM 10AM TO 1PM MONDAY. HIGH
TIDES ARE PREDICTED TO BE AT 7.96 FEET @ 12:14 PM ON TUESDAY. AT
THIS MOMENT, COMBINE WITH SURGE AND ANOMALY IS EXPECTED TO REMAIN
BELOW ADVISORY FOR TUESDAY, BUT THIS CAN CHANGE DEPENDING OF THE
PERSISTING STRONG SOUTHERLY WINDS. -ZVS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
WIND ADVISORY UNTIL 7 AM PST THIS MORNING FOR CAZ101.
WIND ADVISORY UNTIL 10 AM PST THIS MORNING FOR CAZ102-
104>106.
COASTAL FLOOD ADVISORY FROM 10 AM THIS MORNING TO 1 PM PST
THIS AFTERNOON FOR CAZ103.
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR
CAZ107-108.
NORTHWEST CALIFORNIA COASTAL WATERS...
GALE WARNING UNTIL 9 AM PST THIS MORNING FOR PZZ450-455-470-
475.
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