168
FXUS66 KEKA 290912
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
212 AM PDT WED JUL 29 2026
KEY MESSAGES
* MODERATE RISK FOR SNEAKER WAVES ALONG THE LOST COAST AND MENDOCINO
COAST THROUGH WEDNESDAY.
* COASTAL STRATUS LIKELY TO CONTINUE TO FORM EACH NIGHT
* HOT TEMPERATURES RETURN LATE WEEK INTO THE WEEKEND.
* ELEVATED FIRE DANGER RETURNS LATE IN THE WEEK AND AT LEAST INTO
NEXT WEEK WITH INCREASED WIND AND INCREASINGLY HOT, DRY CONDITIONS.
SYNOPSIS
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES FORECAST
FOR THE INTERIOR AREAS, WHILE NEAR TO ABOVE NORMAL COASTAL
TEMPERATURES ARE LIKELY CONTINUE THROUGH WEDNESDAY. BREEZY AFTERNOON
WINDS ELEVATE FIRE DANGER IN EASTERN TRINITY, EASTERN MENDOCINO, AND
LAKE COUNTIES. HOT INTERIOR TEMPERATURES RETURN LATE THIS WEEK WITH
A FURTHER INCREASING FIRE WEATHER RISK.
DISCUSSION
THE EXTENDED PERIOD OF LIGHTER NORTHERLY WINDS HAS
SHUT DOWN MUCH OF THE COASTAL UPWELLING. THIS CONTINUES TO ALLOW FOR
WARMER THAN AVERAGE COASTAL WATER TEMPERATURES, INTO THE LOW 60S,
AND A WEAKER LOW LEVEL INVERSION. THE LACK OF COOL AIR ADVECTION
FROM THE COASTAL WATERS AND QUICKLY DISPERSING DAYTIME STRATUS HAS
FED INTO A POSITIVE FEEDBACK LOOP, MAINTAINING WARMER TEMPERATURES
ALONG THE COAST. THE STRATUS LOOKS TO BE DRIVEN INTO THE NORTH COAST
THROUGH THE AFTERNOON HOURS WEDNESDAY, LIKELY KNOCKING DOWN
TEMPERATURES SLIGHTLY LOWER THAN RECENTLY OBSERVED. INTERIOR
TEMPERATURES WILL OTHERWISE WILL BE NEAR OR BELOW AVERAGE WEDNESDAY
FROM AN ATYPICAL SUMMERTIME TROUGHING PATTERN. A PRONOUNCED
SHORTWAVE PERTURBATION WILL ADVANCE OVER N CA THURSDAY. MOISTURE AND
INSTABILITY WILL BE VERY LIMITED, SO ONLY MID TO HIGH LEVEL CLOUDS
SHOULD RESULT.
A FOUR CORNERS/DESERT SOUTHWEST DOME OF HIGH PRESSURE WILL THEN
BEGIN TO STRENGTHEN THURSDAY. THE 500MB RIDGE WILL CONTINUE TO
STRENGTHEN, REACHING 597 TO UP TO 600DM BY FRIDAY. THIS WILL
TRANSLATE TO HOT INTERIOR TEMPERATURES. PROBABILITIES FOR INTERIOR
TEMPERATURES OVER 100 INCREASE GOING INTO NEXT WEEK, WITH HIGH
CHANCES (60 TO 80%) FOR TEMPERATURES OVER 100 BY MONDAY, AND
MODERATE CHANCES (40%) FOR TEMPERATURES OVER 104 TUESDAY AND
WEDNESDAY OF NEXT WEEK.
FIRE WEATHER CONCERNS WILL BECOME ELEVATED AGAIN WITH THE DURATION
OF THE BUILDING HEAT ALONG WILL PERIODS OF BREEZY CONDITIONS. SEE
THE FIRE WEATHER SECTION BELOW. /JJW
AVIATION
06Z TAFS. STRATUS REFORMED TUESDAY EVENING AFTER PERIODS
OF FULL CLEARING AND VFR CONDITIONS. THE MARINE LAYER HAS REMAINED
DEEPENED FROM BROAD TROUGHING AND PASSING WEAK SHORTWAVES. A SECOND
WEAK SHORTWAVE IS FORECAST TO PASS THROUGH WEDNESDAY. THIS SHOULD
MAINTAIN MOSTLY MVFR TO IFR CEILINGS. STATISTICAL GUIDANCE HAVE
HIGHER CHANCES FOR LIFR CEILINGS AND SOME FOG, BUT THEY HAVE NOT
VERIFIED WELL UNDER THE ATYPICAL SUMMERTIME TROUGHING REGIME.
HIGHEST CHANCES FOR LIFR REMAIN NORTH OVER CEC. COASTAL SEA
SURFACE TEMPERATURES HAVE BEEN WARMER THAN AVERAGE, IN THE LOW
60S, AND THIS HAS CONTRIBUTED TO A LARGELY WEAKENED LOW LEVEL
INVERSION. THERE ARE GROWING INDICATIONS LIGHT NW WINDS WILL POOL
UP STRATUS AROUND HUMBOLDT BAY THROUGH THE AFTERNOON, WHILE
CLEARING OCCURS ELSEWHERE, THOUGH CEILING HEIGHTS SHOULD LIFT TO
MVFR LEVELS. VFR CONDITIONS WILL PREVAIL FOR THE INTERIOR.
NORTHERLY WINDS WILL INCREASE THROUGH THE AFTERNOON HOURS, WITH
SOME GUSTS UP 20 KTS POSSIBLE AT CEC, ACV AND UKI. STRATUS WILL
BEGIN EXPANDING BACK OVER THE COAST WEDNESDAY EVENING, BUT SHOULD
NOT BE INITIALLY TOO SHALLOW. /JJW
MARINE
NORTHERLY WINDS HAVE TRENDED HIGHER OVER ALL ZONES. WINDS
NORTH OF CAPE MENDOCINO LOOK TO GENERALLY REMAIN BELOW 20 KTS
THROUGH FRIDAY. THE FOCUS OF STRONGER NORTHERLIES WILL REMAIN AROUND
AND SOUTH OF CAPE MENDOCINO. NORTHERLIES OF 20-25 KTS IN THESE
SOUTHERN ZONES, LOCALLY WITH GALE CONDITIONS UP TO 30 KTS AROUND THE
CAPE, CAN CONTINUE TO BE EXPECTED. SHORT PERIOD NORTHERLY SEAS WILL
INCREASE OVER THE WATERS, ALONG WITH A SMALL LONG PERIOD
SOUTHERLY SWELL. A RIDGE OF HIGH PRESSURE WILL STRENGTHEN THROUGH
THE WEEKEND, BRINGING INCREASED CHANCES FOR GALE STRENGTH
NORTHERLIES OVER MUCH OF THE WATERS. /JJW
FIRE WEATHER
AFTERNOON WESTERLY BREEZES WILL LIKELY BRING
ISOLATED AREAS OF ENHANCED FIRE WEATHER DANGER AND PERHAPS BRIEF
CRITICAL CONDITIONS LOCALLY. OVERNIGHT RECOVERIES ARE EXPECTED TO BE
MODERATE TO GOOD, ASIDE FROM THE HIGHER ELEVATIONS OF LAKE AND
EASTERN TRINITY COUNTY.
CLOSER TO THE COAST, A DEEP MARINE LAYER BRINGS HIGH RH AND PERHAPS
STRATUS AND/OR FOG INTO THE RIVER VALLEYS OVERNIGHT. AFTERNOON RH
RANGES FROM 60S TO 80S NEAR THE IMMEDIATE COAST TO LOW 20S IN
INTERIOR HUMBOLDT, DEL NORTE, AND WESTERN MENDOCINO COUNTIES
WEDNESDAY.
RIDGING REBUILDS BACK IN STARTING THURSDAY, BRINGING MUCH WARMER
HIGH TEMPERATURES TO THE INTERIOR. MOST VALLEYS ARE FORECAST TO
REACH THE HIGH 90S AND TRIPLE DIGITS, WITH HIGHEST CHANCES FOR
TEMPERATURES OVER 100 EARLY NEXT WEEK. AFTERNOON RHS WILL AGAIN BE
IN THE TEENS AND 20S FOR THE EASTERN INTERIOR. TROUGHING TO THE
NORTH WILL LIKELY ENHANCE WINDS OVER THE WEEKEND AND POSSIBLY
MONDAY, INCREASING THE FIRE WEATHER THREAT, ESPECIALLY WHEN
COINCIDING WITH THE BUILDING HEAT AND LOW RH. /JJW
BEACH HAZARDS
A LONG PERIOD SOUTHERLY SWELL WITH PERIODS UP TO 18
SECONDS REMAINS IN FROM TROPICAL SYSTEMS IN THE EASTERN PACIFIC
THROUGH WEDNESDAY, WITH EASING OF SIZE AND ENERGY THEREAFTER. THIS
ENERGETIC SWELL WILL CONTINUE TO BRING A LOW TO MODERATE RISK OF
SNEAKER WAVES THAT ARE MOST HAZARDOUS ON STEEP, SOUTH AND SOUTHWEST
FACING BEACHES ALONG THE LOST COAST AND MENDOCINO COAST THROUGH
WEDNESDAY.
SNEAKER WAVES ARE A UNIQUE HAZARD, WITH UP TO 30 MINUTES BETWEEN
WAVES. LARGE, UNEXPECTED WAVES CAN SWEEP ACROSS THE BEACH WITHOUT
WARNING, SWEEPING PEOPLE INTO THE SEA FROM ROCKS, JETTIES, AND
BEACHES. THESE SNEAKER WAVES CAN ALSO MOVE LARGE OBJECTS SUCH AS
LOGS, CRUSHING ANYONE CAUGHT UNDERNEATH. EVEN ANKLE TO KNEE DEEP
WATER CAN KNOCK YOU DOWN AND DRAG YOU OUT WHEN A SNEAKER WAVE HITS.
PAY ATTENTION AND STAY ABOVE THE HIGH WATER LINE AND ANY WET SAND TO
STAY SAFE. IF THE GROUND IS WET, WAVES HAVE SURGED THERE RECENTLY.
STAY SAFE AND NEVER TURN YOUR BACK ON THE OCEAN! /JJW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
BEACH HAZARDS STATEMENT THROUGH WEDNESDAY AFTERNOON FOR
CAZ104-109.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 2 PM PDT FRIDAY FOR PZZ455-475.
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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