085
FXUS66 KEKA 020729
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1229 AM PDT SAT MAY 2 2026
SYNOPSIS
THUNDERSTORMS ARE POSSIBLE EACH AFTERNOON THROUGH
MONDAY WITH THE GREATEST STRENGTH AND COVERAGE OF STORMS ON
SUNDAY. DRIER WEATHER IS LIKELY BY MID NEXT WEEK.
KEY MESSAGES
-ISOLATED THUNDERSTORMS (10-20% CHANCE) OVER DEL NORTE, HUMBOLDT,
AND TRINITY COUNTIES THIS AFTERNOON AND EVENING.
-SCATTERED THUNDERSTORMS (15-25% CHANCE) OVER THE THE INTERIOR
SUNDAY AFTERNOON WITH SOME STORMS PUSHING CLOSER TO SHORE.
-STRONG TO SEVERE STORMS ARE POSSIBLE SUNDAY WITH THE POTENTIAL
FOR STRONG OUTFLOW WINDS, DAMAGING HAIL, AND LOCALIZED DOWNPOURS.
DISCUSSION
AN UPPER LOW OFF THE COAST OF NORTHERN CALIFORNIA WILL
CONTINUE TO BRING UNSETTLED CONDITIONS TO THE INTERIOR THROUGH THE
WEEKEND. INCREASED MARINE INFLUENCE AND CLOUD COVER WILL SLIGHTLY
COOL INTERIOR TEMPERATURES WITH HIGHS MOSTLY IN THE MID 70S. LOWER
PRESSURE HAS HELPED LIFT THE MARINE LAYER ONSHORE WITH MOST MODELS
SHOWING STRATUS STICKING AROUND EVEN INTO THE AFTERNOON NEAR THE
COAST.
THE GREATEST IMPACT OF THE SHORTWAVE WILL BE THE POTENTIAL FOR
THUNDERSTORMS OVER THE INTERIOR. WHILE THUNDER ACTIVITY REMAINED OUT
OF THE AREA FRIDAY, CHANCES INCREASE TODAY AS CAPE INCREASES TO
VALUES PEAKING AROUND 1000 TO 1500 J/KG OR HIGHER. THE MAIN ACTIVITY
LOOKS FOCUSED IN TRINITY, INTERIOR HUMBOLDT, AND INTERIOR DEL NORTE.
DESPITE VERY HIGH CAPE, MOISTURE IS STILL A LIMITING FACTOR. UPPER-
LEVEL RHS ARE SLIGHTLY HIGHER THAN ON FRIDAY, HOWEVER, SO THE
ENVIRONMENT IS SLIGHTLY MORE FAVORABLE FOR THUNDERSTORMS. HIGH-RES
MODELS ARE SHOWING LIMITED ACTIVITY BECAUSE OF THE LIMITED MOISTURE,
BUT MOISTURE AND CAPE HAS GENERALLY BEEN TRENDING UPWARDS IN RECENT
MODEL RUNS. BULK SHEAR APPROACHES 20-30 KTS IN INTERIOR HUMBOLDT AND
DEL NORTE, SO SHOULD STORMS DEVELOP (WHICH IS STILL FAIRLY
UNCERTAIN), THEY COULD BE ORGANIZED AND STRONG. STRONGER STORMS
COULD BRING WINDS UP TO 40-50 MPH, HAIL, AND LOCALIZED HEAVY
DOWNPOURS. NORTHEAST FLOW COULD STEER STORMS OVER INTERIOR HUMBOLDT
AND DEL NORTE OVER COASTAL DEL NORTE.
THE SHORTWAVE WILL MORPH INTO A CUTOFF LOW AND TRAVEL DOWN ALONG THE
CALIFORNIA COAST SATURDAY NIGHT 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 ALSO LIKELY TO BE WET, WITH WETTING RAIN
(>0.1") LIKELY FROM ABOUT FORT BRAGG AND NORTHWARD. ISOLATED AREAS
OF HEAVY DOWNPOURS FROM STRONGER STORMS COULD BRING POCKETS OF OVER
1" OF RAIN WITH THE HIGHEST CHANCES IN INTERIOR DEL NORTE. THIS WILL
NEED TO BE WATCHED FOR POTENTIAL FLASH FLOODING, ESPECIALLY OVER THE
BURN SCARS FROM RECENT YEARS.
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. /JB&JHW
AVIATION
A HEAVY BLANKET OF COASTAL STRATUS STRETCHED FROM
DEL NORTE TO THE KING RANGE AND CAPE MENDOCINO BUT BEGAN TO
DISSIPATE TOWARDS 01Z. IMPROVED CONDITIONS FOR KCEC ARE ALREADY IN
PLAY AFTER GUSTY NORTHERLIES HELPED DISSIPATE THE MARINE LAYER.
SOUTHERLY WINDS ARE NOW THE PREVAILING DIRECTION AND WILL CONTINUE
INTO SATURDAY MORNING. FLIGHT CATEGORIES FOR THE OVERNIGHT TAF
PERIOD AT KCEC WILL BE MOSTLY VFR THOUGH A FEW HOURS OF IFR ARE
POSSIBLE WITH CEILINGS BELOW 1000FT. SIMILAR CONDITIONS AT KACV WITH
A GREATER PROBABILITY OF IFR CATEGORIES AT LONGER INTERVALS. KUKI
COULD SEE FOG/STRATUS ADVECTION AS SOUTHERLY WINDS PICK UP EARLY
SATURDAY MORNING. /EYS
MARINE
LOW PRESSURE OVER THE INTERIOR INTERACTING WITH A
SKINNY RIDGE OF HIGH PRESSURE IN THE NE PACIFIC IS REINFORCING THE
STRONG SURFACE PRESSURE GRADIENT OVER THE COASTAL WATERS. THIS
SYNOPTIC SCALE SETUP IS RESULTING IN CONTINUED NORTHERLY WINDS OVER
THE WATERS AS WELL AS LARGE, STEEP SEAS. WHILE THE LARGEST WAVES (UP
TO SIG. HEIGHTS OF 13-15FT) ARE MODELED FOR THE OUTER WATERS, STEEP
SEAS OF 7 TO 9 FT ARE PROPAGATING INTO THE INNERS. NEAR-GALE
CONDITIONS WITH LOCALIZED AREAS OF GALE FORCE GUSTS WILL DEVELOP
DURING THE AFTERNOON 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. AFTER THESE WARNINGS EXPIRE, EXPECT SMALL CRAFT
ADVISORIES TO BE ISSUED FOR THE OUTER WATERS. CONDITIONS HAZARDOUS
TO SMALL CRAFTS ARE BEING OBSERVED FOR THE INNER ZONES DUE CONTINUED
MODERATELY BREEZY WINDS AND STEEP SEAS.
SATURDAY EVENING, AN AREA OF LOW PRESSURE WILL APPROACH THE PACNW
FROM THE GULF OF ALASKA, ALLOWING THE NORTHERLY WINDS TO WEAKEN DOWN
TO GENTLE BREEZY CONDITIONS. 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 6FT@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. A BEACH HAZARDS STATEMENT HAS BEEN ISSUED FOR THE
COAST SUNDAY. 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!
EKA WATCHES/WARNINGS/ADVISORIES
CA...
BEACH HAZARDS STATEMENT FROM THIS EVENING THROUGH SUNDAY
EVENING FOR CAZ101-103-104-109.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 AM PDT THIS MORNING FOR PZZ450-
455.
HAZARDOUS SEAS WARNING UNTIL 9 AM PDT THIS MORNING 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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