944
FXUS66 KEKA 232159
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
259 PM PDT WED APR 23 2025
SYNOPSIS
AN UPPER LEVEL TROUGH APPROACHING THE AREA WILL BRING
COOLER TEMPERATURES EACH ACROSS THE INTERIOR THROUGH SATURDAY.
THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS OVER THE MOUNTAINS EACH
AFTERNOON AS WELL. MORE WIDESPREAD SHOWERS ARE EXPECTED TO BRING
RAIN TO MOST AREAS ON FRIDAY. COOL NIGHTS AND PLEASANT SUNNY
AFTERNOONS WILL RETURN SUNDAY AND INTO NEXT WEEK.
DISCUSSION
WATER VAPOR SATELLITE SHOWS A TROUGH MOVING OVER THE
AREA THIS AFTERNOON. THIS IS BRINGING COOLER TEMPERATURES TO THE
AREA THIS AFTERNOON. QUITE A FEW CUMULUS CLOUDS HAVE DEVELOPED
OVER THE MOUNTAINS, BUT AS OF 1:30PM THEY ARE FAIRLY FLAT. THESE
MAY PRODUCE A SHOWER OR EVEN A LIGHTNING STRIKE, BUT CONFIDENCE IS
LOW ON THIS. TONIGHT FROST IS POSSIBLE AGAIN IN THE COLDEST
VALLEYS OF TRINITY COUNTY, BUT WITH ALL THE CU AROUND IT MAY KEEP
TEMPERATURES IN THE UPPER 30S. SO FOR NOW HAVE NOT ISSUED A FROST
ADVISORY. CLOSER TO THE COAST WIDESPREAD MARINE CLOUDS ARE
EXPECTED TO DEVELOP AROUND SUNSET OR SHORTLY AFTER. THURSDAY
AFTERNOON INLAND AREAS ARE EXPECTED TO SEE A NUMBER OF SHOWERS AND
POSSIBLY SOME THUNDERSTORMS AS WELL. CAPE VARIES QUITE A BIT OF
MODEL TO MODEL, BUT THE HREF MEAN IS SHOWING AROUND 200 J/KG.
SHEAR IS ONLY AROUND 20 KT AND MID LEVEL LAPSE RATES ARE GENERALLY
AROUND 6.5 TO 7C/KM. THIS WILL LIKELY BE ENOUGH TO GENERATE A FEW
THUNDERSTORMS THURSDAY AFTERNOON.
THURSDAY NIGHT INTO FRIDAY SHOWERS ARE EXPECTED TO BECOME MORE
WIDESPREAD AS THE UPPER LEVEL TROUGH MOVES. THERE IS THE
POTENTIAL FOR SOME THUNDERSTORMS AGAIN FRIDAY AFTERNOON, BUT IN
GENERAL IT LOOKS LIKE THERE WILL BE TOO MANY CLOUDS AROUND TO
GENERATE ENOUGH DAYTIME HEATING AND INSTABILITY. SATURDAY THE
UPPER LEVEL LOW STARTS TO MOVE OUT OF THE AREA, BUT THERE IS
EXPECTED TO BE A RESURGENCE OF SHOWERS IN THE AFTERNOON WITH THE
DAYTIME HEATING. HIGH TEMPERATURES ACROSS THE AREA EXPECTED TO
STRUGGLE TO BREAK 60 DEGREES EVEN IN THE WARMER AREAS. OVERNIGHT
LOWS ARE NOT EXPECTED TO DROP TOO MUCH DUE TO THE MOISTURE AND
CLOUDS AROUND. ANY AREAS THAT DO REMAIN CLEAR SATURDAY NIGHT COULD
SEE SOME FROST.
SUNDAY CLEARING SKIES ARE EXPECTED AND TEMPERATURES WILL START TO
WARM BACK UP AGAIN. INLAND AREAS ARE EXPECTED TO SEE HIGHS IN THE
60S. SUNDAY NIGHT INTO MONDAY MORNING IS EXPECTED TO BE THE
COLDEST NIGHT AND FROST IS POSSIBLE IN THE COLDER VALLEYS. HIGH
PRESSURE CONTINUES TO BUILD IN THROUGH THE WEEK WITH HIGHS AROUND
80 FOR THE INLAND AREAS BY WEDNESDAY. MKK
AVIATION
BANKS OF FOG PREVAILED ALONG MUCH OF THE NORTH COAST THIS
MORNING...ESPECIALLY OVER HUMBOLDT BAY TO ACV WHERE A THIN LAYER
LINGERED INTO EARLY AFTERNOON. HOWEVER, WEBCAM AND SATELLITE IMAGERY
SHOWED A DIFFERENT PICTURE. PERHAPS THE LINGERING BKN017 LAYER AT
ACV (BECAME SCT018 AT 1324 LST) CAN BE ATTRIBUTED TO SEA SPRAY? LOW
CLOUDS OVER MENDOCINO COULD NOT OVERTOP THE COASTAL RANGE...
THEREFORE UKI REMAINED SKC. A WEAKER COASTAL GRADIENT RESULTED IN
LESS GUSTY WINDS AT CEC. OVERNIGHT/THURSDAY: ALL MODEL GUIDANCES
RETURN STRATUS ALONG THE COAST, WITH CIGS EXPECTED FROM LOW MVFR TO
IFR, MOST NOTABLY AT ACV. RIVER VALLEYS WILL ALSO DEVELOP STRATUS
WITH UKI POSSIBLY GETTING A BRIEF MORNING PERIOD OF IFR/MVFR CIGS.
BY LATER DAY THURSDAY, LOCAL AIRPORTS COULD BE SLIGHTLY IMPACTED BY
WEAK CONVECTION/SHOWERS. /TA
MARINE
NORTHERLY WINDS ARE EASING AND WILL CONTINUE TO TREND
DOWNWARD TONIGHT. SEAS WILL DROP BELOW 10 FOOT IN ALL ZONES GOING
INTO EARLY THURSDAY MORNING, BUT ADVISORY LEVEL STEEP SEAS WILL BE
SLOWER TO DROP OFF GOING INTO MIDDAY THURSDAY. OF NOTE, THERE WILL
BE A PRONOUNCED AND PERSISTENT WIND EDDY FOR THE FAR NORTHERN INNER
ZONE AND AROUND POINT ST GEORGE STARTING TONIGHT AROUND 8 PM. THE
RESULTING LOCALIZED SOUTHERLY RETURN FLOW WILL GENERATE SOUTHERLY
WINDS WITH GUSTS UP TO OVER OVER 18 KTS TONIGHT. IN FACT, MODELS
RETAIN THIS FEATURE THROUGH MOST OF THURSDAY.
A WEATHER SYSTEM WILL MOVE IN ON THURSDAY AND WEAKEN THE PRESSURE
GRADIENT. AS A RESULT, WINDS THURSDAY AFTERNOON WILL GENERALLY RANGE
FROM 10 TO 15 KTS, WITH LOWER WINDS AND SEAS OF 5 FT ON FRIDAY.
BEHIND THIS SYSTEM, NORTHERLY WINDS WILL THEN BEGIN SLOWLY
INCREASING FRIDAY NIGHT, AND WILL CONTINUE STRENGTHENING THROUGH
SATURDAY. WINDS OF UP TO 25 KTS ARE FORECAST SATURDAY EVENING, AND
THIS SIMILAR MAGNITUDE OF NORTHERLY WINDS CAN BE EXPECTED INTO NEXT
WEEK. THERE IS CURRENTLY A LOW PROBABILITY FOR WINDS OVER 25 KTS (30-
40%) THROUGH THAT PERIOD, AND MAINLY FOR THE AFTERNOONS SOUTH OF
CAPE MENDOCINO AND POINT ST GEORGE. /JJW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR PZZ450-455.
SMALL CRAFT ADVISORY UNTIL 11 AM PDT THURSDAY FOR PZZ470-475.
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