318
FXUS66 KEKA 302105
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
205 PM PDT THU APR 30 2026
SYNOPSIS
GENERALLY WARM AND CALM CONDITIONS WILL PERSIST FRIDAY
WITH SLIGHT COOLING THIS WEEKEND. FRIDAY AND SATURDAY WILL SEE
ISOLATED THUNDERSTORMS OVER THE INTERIOR MOUNTAINS WITH BROADER AND
STRONGER STORM POTENTIAL SUNDAY.
KEY MESSAGES
-WARM AND DRY CONDITIONS WILL CONTINUE FRIDAY WITH A WEAK MARINE
LAYER NEAR SHORE
-ISOLATED THUNDERSTORMS (10-15% CHANCE) OVER THE EASTERN INTERIOR
FRIDAY AND SATURDAY AFTERNOON.
-SCATTERED AND STRONG THUNDERSTORMS (15-25% CHANCE) OVER THE THE
INTERIOR SUNDAY AFTERNOON WITH SOME STORMS PUSHING CLOSER TO SHORE.
DISCUSSION
WEAK HIGH PRESSURE HAS BEGUN TO PEAK TODAY WITH
INTERIOR HIGHS IN THE UPPER 70S TO LOW 80S UNDER MOSTLY CLEAR AND
DRY CONDITIONS. A BROKEN MARINE LAYER HAS PERSISTED NEAR THE COAST
THANKS TO A BUILDING MARINE INVERSION.
A WEAK SHORTWAVE APPROACHING THE AREA FRIDAY AND INTO THE WEEKEND
WILL BRING SOMEWHAT MORE UNSETTLED CONDITIONS. INCREASED MARINE
INFLUENCE AND CLOUD COVER WILL SLIGHTLY COOL INTERIOR TEMPERATURES
WITH HIGHS MOSTLY IN THE MID 70S BY SATURDAY. LOWER PRESSURE WILL
HELP LIFT THE MARINE LAYER ONSHORE, THOUGH MOTH MODELS SHOW AT LEAST
SOME MARINE STRATUS STICKING AROUND.
THE GREATEST IMPACT OF THE SHORTWAVE WILL BE THE POTENTIAL FOR
THUNDERSTORMS OVER THE INTERIOR. BEGINNING FRIDAY AFTERNOON, DAYTIME
CAPE VALUES WILL BEGIN TO APPROACH 1000 J/KG OVER THE EASTERN
INTERIOR. PRECIPITABLE WATER, HOWEVER, WILL BE VERY MARGINAL
GENERALLY BETWEEN 0.4 AND 0.8 INCHES. SUCH FACTORS WILL COMBINE TO
CREATE ISOLATED THUNDERSTORMS (10 TO 15% CHANCE) OVER THE INTERIOR.
CHANCES WILL BE GREATEST AND FAR EASTERN TRINITY, MENDOCINO, AND
LAKE COUNTIES ALONG THE RIM OF THE SACRAMENTO VALLEY. VERY SIMILAR
CONDITIONS ARE EXPECTED SATURDAY, THOUGH MOST CONVECTIVE MODELS SHOW
A SLIGHT REDUCTION IN THUNDER CHANCES (GENERALLY LESS THAN 15%).
THE SHORTWAVE WILL MORPH INTO A CUTOFF LOW AND TRAVEL DOWN ALONG THE
CALIFORNIA COAST SATURDAY INTO SUNDAY. TROPICAL AIR WRAPPING UP THE
SACRAMENTO VALLEY WILL BRING MUCH MORE MOISTURE TO THE AREA WITH
PRECIPITABLE WATER OVER 1.2 INCHES. COMBINED WITH INCREASING WIND
SHEAR AND STILL SOLID CAPE, THE CHANCES FOR THUNDERSTORMS WILL BE
MUCH GREATER ON SUNDAY. STORM CHANCES OVER THE INTERIOR ARE AROUND
25% WITH GREATER POTENTIAL FOR STORMS TO PUSH EAST TO WEST INTO THE
COAST (10 TO 15% CHANCE OF STORMS ALONG THE HUMBOLDT AND DEL NORTE
COAST). SOME OF THE STORMS OVER THE INTERIOR HOLD THE POTENTIAL TO
BE SEVERE WITH STRONG OUTFLOW WINDS AND ISOLATED DAMAGING HAIL.
STORMS ARE MOST LIKELY TO BE WET, SO MUCH SO THAT NBM CURRENTLY
PLACES A 0.1 TO 0.3 INCHES OF RAIN ALL ACROSS THE NORTHERN HALF OF
THE AREA ON SUNDAY.
STORMS WILL LIKELY LEAVE BEHIND COOLER AND CLOUDIER CONDITIONS FOR
NEXT MONDAY, THOUGH MOISTURE AND CLOUDS WILL GENERALLY LIMIT ANY
FROST OR FREEZE CONCERNS. GENERALLY CALM AND WARM CONDITIONS WILL
MOST LIKELY BUILD FOR THE REMAINDER OF NEXT WEEK.
AVIATION
SATELLITE IMAGERY SHOWS COASTAL STRATUS EVAPORATING
CLOSE TO COASTAL TERMINALS SITES. A LARGE BANK OF STRATUS CONTINUES
TO EXIST OVER THE PACIFIC. THERE IS HIGH CONFIDENCE (>70%) OF THIS
STRATUS DECK RETURNING OVER THE COASTAL TERMINALS THIS
AFTERNOON/EVENING. A SLIGHT (~30%) CHANCE OF DRIZZLE IS POSSIBLE FOR
BOTH KACV AND KCEC THIS EVENING INTO FRIDAY MORNING. NORTHERLY WINDS
WILL BUILD THROUGH THE DAY AS WELL. INLAND, VFR IS EXPECTED WITH
GUSTY WINDS CLOSE TO RIDGETOPS. NORTHERLY WINDS ARE FORECASTED TO
CONTINUE INLAND AS WELL, WITH N-S ORIENTATED VALLEYS HAVING STRONG
FLOW COMPARED TO OTHER PROTECTED AREAS.
MARINE
LOW PRESSURE OVER THE INTERIOR INTERACTING WITH HIGH
PRESSURE IN THE NE PACIFIC IS STRENGTHENING THE SURFACE PRESSURE
GRADIENT. THIS SETUP IS RESULTING IN NORTHERLY WINDS STRENGTHENING
OVER THE WATERS, LEADING TO LARGE, STEEP SEAS. WHILE THE LARGEST
WAVES ARE MODELED FOR THE OUTER WATERS, STEEP SEAS OF 7 TO 9 FT ARE
PROPAGATING INTO THE INNERS AS WELL. NEAR-GALE TO GALE CONDITIONS
WILL PERIODICALLY DEVELOP EACH AFTERNOON OVER THE WATERS THROUGH
SATURDAY. GALE STRENGTH GUSTS WILL BE MORE PERSISTENT AROUND AND
SOUTH OF CAPE MENDOCINO, YET COVERAGE IS TOO LOW TO WARRANT A
WIDESPREAD GALE WARNING FOR THE SOUTHERN WATERS. HAZARDOUS SEAS
WARNINGS PERSIST OVER THE OUTER ZONES TO ACCOUNT FOR THE PERIODS OF
LIGHT GALES BUT MORE IMPORTANTLY THE CONTINUED LARGE, STEEP SEAS.
CONDITIONS HAZARDOUS TO SMALL CRAFTS ARE BEING OBSERVED FOR THE
INNER ZONES DUE WINDS UP TO 20-25 KTS AND STEEP SEAS OF 7 TO 10 FT.
AN AREA OF LOW PRESSURE WILL APPROACH THE AREA SATURDAY, ALLOWING
THE NORTHERLY WINDS TO SUBSIDE THROUGH SATURDAY EVENING. THIS WILL
BEGIN AN EXTENDED PERIOD OF LIGHTER WINDS AND SMALLER SEAS WHICH MAY
CARRY INTO NEXT WEEK. THE GFS GLOBAL WATER SHOWS A LONG PERIOD SWELL
FILLING INTO THE WATERS SATURDAY AFTERNOON. AS IT ARRIVES, THE SWELL
IS FORECASTED TO BE AROUND 2FT@20S BEFORE BUILDING UP TO 7FT@15S BY
SUNDAY EVENING.
BEACH HAZARDS
ON SUNDAY, A LONG PERIOD NORTHWEST SWELL WITH
PERIODS BETWEEN 16-19 SECONDS WILL ARRIVE. THIS SWELL CONTINUES TO
BE MONITORED AS IT MAY POSE A MODERATE RISK OF SNEAKER WAVES FOR
COASTAL AREAS. SHOULD THIS SWELL CONTINUE AS MODELED, A BEACH HAZARD
STATEMENT IS MORE LIKELY THAN NOT TO BE HOISTED. SNEAKER WAVES ARE
ANOMALOUSLY LARGE, UNEXPECTED WAVES THAT SWEEP ACROSS BEACHES
WITHOUT WARNING. THERE CAN BE UP TO 30 MINUTES OF SMALLER WAVES
BEFORE A SNEAKER WAVE ARRIVES TO THE SHORELINE. CHOOSE YOUR
RECREATION WISELY BY AVOIDING STEEP BEACHES AND JETTIES AS WELL AS
STAYING MUCH FARTHER BACK FROM THE OCEAN THAN NORMAL. NEVER TURN
YOUR BACK ON THE OCEAN! DS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 AM PDT SATURDAY FOR PZZ450-455.
HAZARDOUS SEAS WARNING UNTIL 9 AM PDT SATURDAY FOR PZZ470-
475.
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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