323
FXUS66 KEKA 272137
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
237 PM PDT MON APR 27 2026
SYNOPSIS
A CHANCE FOR INTERIOR SHOWERS AND THUNDERSTORMS
ANTICIPATED LATE THIS AFTERNOON, WITH PROBABILITIES DECREASING
INTO LATE EVENING. DRIER WEATHER RETURNS TUESDAY/WEDNESDAY WITH A
SHALLOW MARINE LAYER EXPECTED ALONG THE COAST EACH NIGHT THE REST
OF THIS WEEK.
DISCUSSION
THE INFLUENCE OF AN UPPER LEVEL TROUGHING PATTERN
SOUTH OF NORTHWEST CALIFORNIA CONTINUES TO WEAKEN AS THE PATTERN
MOVES OFF TO THE EAST. HOWEVER, THERE IS STILL A SLIGHT RISK OF
THUNDERSTORMS (ABOUT A 10 TO 20 PERCENT CHANCE) FOR THE INTERIOR
THIS AFTERNOON/EVENING. THE HIGHEST CHANCE (15 TO 20 PERCENT) IS FOR
TRINITY AND EXTREME NE MENDOCINO; WITH LESS OF A CHANCE FOR INTERIOR
HUMBOLDT, MOST OF INTERIOR MENDOCINO, AND NORTHERN LAKE COUNTIES
(AROUND 10 PERCENT). ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO TAPER OFF BEFORE SUNSET TODAY.
MODELS INDICATE A PREVAILING RIDGING PATTERN TO DEVELOP FOR THE REST
OF THIS WEEK. MODEL SOUNDINGS SHOW DRYER AIR ALOFT WITH AN
INVERSION, A PRELUDE TO SEASONAL WARMING AND STABILITY IN THE
VERTICAL PROFILE. A SHALLOW MARINE LAYER ALONG THE COAST IS
EXPECTED, TO SOME DEGREE, EACH NIGHT/EARLY MORNING THIS WEEK.
DETERMINISTIC ENSEMBLES ARE NOT IN AGREEMENT OVER THE NEXT
PRECIPITATION EVENT FOR THE FIRST WEEK OF MAY. STAY TUNED AS TIME
DRAWS NEAR FOR DEVELOPMENTS. /EYS&JLW
AVIATION
COASTAL CLOUDS HAVE MOSTLY DISSIPATED EXCEPT FOR A SMALL AREA RIGHT
AROUND ARCATA BAY. VFR CONDITIONS SHOULD CONTINUE ALONG THE COAST
THROUGH THE EVENING HOURS. MODEL GUIDANCE INDICATES MOISTURE WILL
ONCE AGAIN INCREASE THROUGH THE EVENING ALLOWING POTENTIALLY MVFR
CEILINGS TO REDEVELOP, PARTICULARLY NORTH OF CAPE MENDOCINO ALONG THE
HUMBOLDT AND DEL NORTE COASTS. SURFACE CONDENSATION PRESSURE
DEFICITS ARE NOT VERY LOW, LIKELY INDICATING A STRATUS DECK RATHER
THAN SURFACE FOG.
FARTHER INLAND SHOWERS HAVE FORMED OVER THE HIGHER TERRAIN AND
PATCHY AREAS OF MVFR OR LOWER CONDITIONS ARE LIKELY OCCURRING.
HOWEVER, IN GENERAL VFR IS PREVAILING, SUCH AS AT UKI. SHOWERS WILL
COME TO AN END DURING THE EVENING HOURS AS INSTABILITY DECREASES.
SOME VALLEY CLOUDS ARE LIKELY TO DEVELOP WHERE MOISTURE POOLS
OVERNIGHT. /RPA
MARINE
THE COASTAL ENVIRONMENT WILL BE DOMINATED BY LOWERING PRESSURE
ACROSS THE INTERIOR WEST AND HIGH PRESSURE BUILDING OVER THE EASTERN
PACIFIC. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN OVER THE
NEXT SEVERAL DAYS AND NORTH WINDS TO RAMP-UP TO NEAR GALE OR GALE ON
FRIDAY INTO SATURDAY. STEEP SEAS WILL BUILD IN RESPONSE TO THE WINDS
WITH SEAS EXCEEDING 10 FEET AT AROUND 8 TO 9 SECONDS IN THE OUTER
WATER ZONES. LOCAL MODEL GUIDANCE HAS BEEN TRYING TO PUSH FOR LARGER
WAVES APPROACHING 15 FEET IN THE OUTER WATERS ON FRIDAY. EITHER WAY,
THE SEAS WILL BE STEEP AND EITHER HAZARDOUS SEAS WARNINGS OR GALE
WARNINGS WILL LIKELY BE NEEDED LATE IN THE WEEK INTO THE FIRST PART
OF THE WEEKEND FOR AT LEAST THE OUTER WATER ZONES. /RPA
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 1 PM TUESDAY TO 11 PM PDT
WEDNESDAY FOR PZZ470.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 PM PDT
WEDNESDAY FOR PZZ475.
NOTE: THE FULL FORECAST DISCUSSION IS NOW REGULARLY ISSUED BETWEEN
10 AM/PM AND 1 PM/AM. ADDITIONAL UPDATES WILL BE ISSUED AS NEEDED.
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