171
FXUS66 KEKA 090816
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
116 AM PDT THU JUL 9 2026
KEY MESSAGES
* COASTAL STRATUS AND FOG: MARINE LOW CLOUDS AND AREAS OF FOG
WILL AFFECT THE IMMEDIATE COAST, BRINGING COOL DAYTIME
TEMPERATURES AND OVERNIGHT DAMPNESS.
* INTERIOR HEAT: AN UPPER-LEVEL RIDGE WILL EXPAND WESTWARD,
CAUSING TEMPERATURES TO RISE WELL ABOVE NORMAL ACROSS INLAND
VALLEYS INCLUDING LAKE, TRINITY, AND INTERIOR MENDOCINO COUNTIES
THROUGH THE WEEKEND.
SYNOPSIS
SHALLOW COASTAL STRATUS AND FOG WILL PERSIST ALONG THE
IMMEDIATE COAST WITH LIMITED AFTERNOON CLEARING THROUGH FRIDAY.
INLAND AREAS WILL REMAIN DRY AND HOT UNDER A BUILDING UPPER-LEVEL
RIDGE.
DISCUSSION
AN UPPER-LEVEL RIDGE OVER THE SOUTHWEST US IS
EXPANDING WESTWARD OVER NORTHWEST CALIFORNIA. SUBSIDENCE ALOFT IS
COMPRESSING THE MARINE LAYER, KEEPING IT SHALLOW AND CONFINED TO
THE COAST AND ADJACENT LOWER VALLEYS. INLAND AREAS WILL EXPERIENCE
WARMING, WITH AFTERNOON HIGH TEMPERATURES IN THE MID TO UPPER 90S
BECOMING WIDESPREAD ACROSS THE INTERIOR VALLEYS OF TRINITY,
MENDOCINO, AND LAKE COUNTIES THIS AFTERNOON.
EARLY NEXT WEEK, THE PLACEMENT OF THE UPPER RIDGE WILL DETERMINE
THE TRACK OF POTENTIAL MONSOONAL MOISTURE. CURRENT GUIDANCE
INDICATES A CONTINUING WARM TREND FOR THE INTERIOR, WITH A LOW
PROBABILITY OF THUNDERSTORM DEVELOPMENT OVER NORTHEASTERN TRINITY
COUNTY.
AVIATION
A COMPRESSED MARINE LAYER HAS BROUGHT LOW CEILINGS AND
REDUCED VISIBILITIES TO COASTAL LOCATIONS. AT KACV, IFR TO LIFR
CONDITIONS IN STRATUS AND FOG WILL PERSIST THROUGH MID-MORNING
BEFORE GRADUAL CLEARING. TEMPORARY SOUTHERLY SURFACE WINDS AT KACV
AND KCEC OVERNIGHT INDICATE LOCALIZED COASTAL EDDY DEVELOPMENT
RATHER THAN A SUSTAINED SOUTHERLY WIND PATTERN. CLEAR SKIES ARE
FORECAST FOR KUKI.
MARINE
THE SURFACE PRESSURE GRADIENT BETWEEN AN OFFSHORE
SURFACE HIGH PRESSURE SYSTEM AND AN INLAND SURFACE THERMAL LOW IS
TIGHTENING. SOUTH OF CAPE MENDOCINO, SUSTAINED NORTHWEST WINDS OF
20 TO 25 KNOTS ARE GENERATING STEEP, WIND-DRIVEN SEAS. A GALE
WATCH IS IN EFFECT FOR THE SOUTHERN OUTER WATERS STARTING AT 5 AM
THURSDAY MORNING THROUGH THURSDAY EVENING DUE TO POTENTIAL GUSTS
UP TO 40 KNOTS, WITH CONDITIONS BEING MONITORED FOR A POTENTIAL
UPGRADE TO A GALE WARNING. FOR THE NORTHERN OUTER WATERS, WINDS OF
20 TO 25 KNOTS COMBINED WITH STEEP 9-FOOT WAVES AT SHORT 8-SECOND
PERIODS SATISFY ADVISORY CRITERIA. ALL COASTAL MARINE ZONES ARE
CURRENTLY UNDER A SMALL CRAFT ADVISORY.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 11 AM PDT FRIDAY FOR PZZ415-450.
SMALL CRAFT ADVISORY UNTIL 10 PM PDT FRIDAY FOR PZZ455-470.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT EARLY THIS MORNING FOR
PZZ475.
GALE WATCH FROM 5 AM PDT EARLY THIS MORNING THROUGH THIS
EVENING 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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