693
FXUS66 KEKA 171218
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
418 AM PST TUE DEC 17 2024
SYNOPSIS
MOSTLY DRY CONDITIONS ARE EXPECTED TODAY EXCEPT FOR
SOME EARLY MORNING SHOWERS IN DEL NORTE AND NORTHERN HUMBOLDT
COUNTIES. ANOTHER CHANCE FOR LIGHT RAIN IS EXPECTED ON WEDNESDAY
FOLLOWED BY WARM TEMPERATURES ON THURSDAY. A MORE ACTIVE PATTERN
WITH STRONGER FRONTAL SYSTEMS IS PROBABLE THROUGH THE WEEKEND AND
LIKELY NEXT WEEK.
DISCUSSION
A WARM FRONT IS CONTINUING TO BRING CLOUDY CONDITIONS TO NORTHWEST
CALIFORNIA THIS MORNING WITH SOME LIGHT RAIN OR SPRINKLES SHOWING ON
RADAR OVER PRIMARILY DEL NORTE COUNTY NORTH INTO OREGON. AS THIS
WARM FRONT CONTINUES TO MOVE INLAND AND NORTH, ANY LINGERING
RAINFALL SHOULD COME TO AN END THIS MORNING LEAVING A DRY DAY FOR
NORTHWEST CALIFORNIA WITH RIDGING ALOFT. SOME FILTERED SUNSHINE IS
POSSIBLE ACROSS THE INTERIOR TODAY BUT OTHERWISE OVERCAST SKIES WILL
PERSIST INTO TONIGHT.
A WEAKENING COLD FRONT WILL APPROACH THE HUMBOLDT AND DEL NORTE
COASTS TONIGHT BRINGING WITH IT SOME LIGHT RAIN TO THE THOSE
COUNTIES AND POSSIBLY TRINITY COUNTY ON WEDNESDAY. TOTAL RAINFALL
AMOUNTS ARE EXPECTED TO BE LESS THAN A HALF INCH IN DEL NORTE
COUNTY TO AS LITTLE AS ONLY A TRACE INTO SOUTHERN TRINITY AND
SOUTHERN HUMBOLDT COUNTIES.
RIDGING WILL RETURN ON THURSDAY AS THE COLD FRONT WEAKENS AND
RETREATS BACK NORTH AS A WARM FRONT. TEMPERATURES WILL WARM QUITE A
BIT ACROSS THE INTERIOR WITH NEAR RECORD HIGH TEMPERATURES AROUND 70
DEGREES POSSIBLE IN UKIAH. HOWEVER, THE WARMTH AND DRY CONDITIONS
WILL QUICKLY END AS EARLY AS FRIDAY AS A DEEP TROUGH DEVELOPS
OVER THE EASTERN PACIFIC AND ONSHORE FLOW RETURNS. THE FIRST
CHANCE WILL BE A QUICK PASSING UPPER SHORTWAVE WHICH COULD BRING
RAIN AND SOME GUSTY CONDITIONS PRIMARILY TO THE HUMBOLDT AND DEL
NORTE AREAS FOLLOWED BY A RETURN TO MORE PERSISTENT STORMY
CONDITIONS OVER THE WEEKEND INTO EARLY NEXT WEEK ACROSS THE ENTIRE
REGION.
THE WEATHER PREDICTION CENTER HAS PLACED MUCH OF NORTHWEST
CALIFORNIA IN A MARGINAL RISK OF EXTREME RAINFALL IN THEIR DAY 5,
SATURDAY OUTLOOK WHILE THE CLIMATE PREDICTION CENTER (CPC) IS
FAVORING ABOVE NORMAL PRECIPITATIONS FOR NORTHWEST CALIFORNIA AND
THE PACIFIC NORTHWEST IN THEIR 6-10 AND 8-14 DAY OUTLOOKS.
ADDITIONALLY, THE CPC IS HIGHLIGHTING OUR REGION FOR HEAVY
PRECIPITATION FROM DECEMBER 24TH THROUGH THE 27TH WITH FLOODING
POSSIBLE. ALL OF THIS IS TO SAY THE PATTERN IS DEFINITELY
INDICATING A TREND TOWARD IMPACTFUL STORM SYSTEMS BEGINNING THIS
COMING WEEKEND, LASTING WELL INTO THE HOLIDAY WEEK. MORE DETAILS
ABOUT THESE STORMS WILL BE COMING AS WE GET CLOSER OVER THE NEXT
SEVERAL DAYS.
AVIATION
WHILE VERY WEAK SHOWERS AND MVFR CONDITIONS HAVE LINGERED
OVERNIGHT ON THE FAR NORTHERN COAST NEAR CRESCENT CITY, GENTLE
OFFSHORE FLOW HAS GENERALLY ALLOWED FOR VFR CONDITIONS ALONG
SHORE. VFR CONDITIONS WILL PREVAIL FOR MOST OF THE DAY WITH GUSTY
SOUTH WINDS UP TO 25 KTS BEING THE ONLY HAZARD FOR COASTAL
TERMINALS. VERY LIGHT RAIN AND MVFR TO IFR CONDITION WILL RETURN
TO THE FAR NORTHERN COAST EARLY WEDNESDAY MORNING WITH A LESSER
CHANCE (30% CHANCE) OF MVFR CEILINGS SPREADING EVEN AS FAR SOUTH
AS HUMBOLDT BAY.
MEANWHILE ABUNDANT VALLEY FOG AND LOW CLOUDS HAVE GENERATED
IFR CONDITIONS FOR MOST INLAND VALLEYS. INLAND LOCATIONS WILLS LOWLY
CLEAR THROUGH THE DAY, WITH DRIER A CLEARER CONDITIONS FOR MOST
LOCATIONS INTO WEDNESDAY MORNING. FOR EXAMPLE, MODELS ARE ONLY
PLACING A 20% CHANCE OF A REPEAT FOR IFR CEILINGS IN UKIAH. /JHW
MARINE
SOUTHERLY WIND HAVE GENERALLY DECREASED ACROSS THE WATERS OVER
THE LAST 24 HOURS, BUT A WEAK FRONT MOVING INTO THE OREGON COAST
TODAY WILL MAINTAIN AT LEAST MODERATE SOUTHERLY WINDS IN THE
NORTHERN WATERS WITH GUSTS UP TO 28 KTS AND SHORT PERIOD WAVES
OVER 8 FEET. SOUTHERLIES WILL BE NOTABLY CALMER IN THE SOUTHERN
WATERS WITH SPEEDS MOSTLY BELOW 12 KTS. THAT SAID, A MID PERIOD
WESTERLY SWELL WILL GRADUALLY BUILD THROUGH THE DAY, KEEPING SEAS
ABOVE 10 FEET IN THE SOUTH DESPITE CALMER WINDS.
SOUTHERLY WINDS WILL CALM ACROSS ALL THE WATERS DURING THE DAY
WEDNESDAY WITH WESTERLY SWELLS DECAYING BELOW 10 FEET. CALMER
CONDITIONS WILL PREVAIL AT LEAST BRIEFLY THROUGH THURSDAY. ANOTHER
STRONGER STORM SYSTEM WILL BEGIN TO INFLUENCE THE WATERS OF FRIDAY
WITH A 40 TO 60% CHANCE OF GALE FORCE SOUTHERLY WINDS AND ASSOCIATED
STEEP SEAS BY FRIDAY AFTERNOON. THERE IS EVEN HIGHER CONFIDENCE (80%
CHANCE) OF GALE FORCE WINDS ACROSS THE WATERS BY SATURDAY. THIS
STORM WILL ALSO MOST LIKELY GENERATE A STEEP WESTERLY SWELL
CURRENTLY MODELED BETWEEN 15 AND 20 FEET BY THE WEEKEND. /JHW
COASTAL FLOODING
THE HIGH TIDE CYCLE IS BEGINNING TO DECREASE IN AMPLITUDE WITH THE
NORTH SPIT ASTRONOMICAL TIDE EXPECTED TO BE 0.4 FEET LOWER TODAY
THAN YESTERDAY'S HIGH TIDE. WITH THE STORM SURGE ALSO TRENDING
DOWN, THE PREDICTED TOTAL TIDE BASED ON THE SURGE TREND IS NOW
ONLY EXPECTED TO REACH 8.6 TO 8.8 FEET. CONSIDERING THIS MOST
LIKELY PLACES THE TIDE BELOW ADVISORY CRITERIA, HAVE OPTED TO NOT
ISSUE ANOTHER COASTAL FLOOD ADVISORY FOR THE HUMBOLDT BAY AREA AT
THIS TIME. THE DAY SHIFT WILL NEED TO TAKE ANOTHER LOOK AT THE
TREND THIS MORNING TO SEE IF THE SURGE INCREASES AGAIN. HIGH TIDE
IS AT NOON TODAY AT THE NORTH SPIT.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 PM PST WEDNESDAY FOR PZZ450-
455-470-475.
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