748
FXUS66 KEKA 150705
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1205 AM PDT FRI AUG 15 2025
SYNOPSIS
WARM WEATHER WILL CONTINUE TO RAPIDLY DECLINE AS GUSTY
NORTHWEST WINDS HELP PULL IN COOLER MARINE AIR FRIDAY. COOL WEATHER
WILL CONTINUE THIS WEEKEND WITH MIDLEVEL CLOUDS AND POSSIBLY EVEN
WETTING RAIN FOR THE NORTHERN HALF OF THE AREA.
DISCUSSION
HIGH PRESSURE CONTINUES WITH A DEEP WAVE TROUGH
DIPPING ACROSS THE PACIFIC NORTHWEST, MAKING ITS EFFECTS ON THE
AREA. GUSTY NORTHWEST WINDS CONTINUE FRIDAY WITH THE STRONGEST
GUSTS ALONG NEAR COASTAL RIDGES AS WELL AS INTERIOR WESTERN FACING
RIDGES. PRIMARILY THE AREAS OF LAKE AND MENDOCINO COUNTIES ARE OF
CONCERN AS DRY CONDITIONS RAISE FIRE DANGERS. THE TROUGHS
INFLUENCE WILL STRENGTHEN FRIDAY AFTERNOON WITH MIDLEVEL CLOUDS
BEGINNING TO MOVE OVER THE AREA AND HIGHS PULLING BACK FURTHER
BELOW 90 FOR THE INTERIOR. ALONG THE COAST, THE MARINE LAYER WILL
PERSIST AND DEEPEN, GENERALLY ENHANCING COOL AND MOIST CONDITIONS.
THE HIGHEST UNCERTAINTY IN THE FORECAST REMAINS WITH THE POTENTIAL
RAINFALL THIS WEEKEND. THERE IS HIGH CONFIDENCE THAT A PLUME OF
MOISTURE REMINISCENT OF AN ATMOSPHERIC RIVER WILL ACCOMPANY THE DEEP
TROUGH (PRECIPITABLE WATER 1 TO 1.5 INCHES), BUT THERE IS MUCH LESS
CERTAINTY REGARDING EITHER INSTABILITY OR LIFT SUFFICIENT TO PRODUCE
RAIN. CURRENTLY, THERE REMAINS A WIDE RANGE IN THE FORECAST, THOUGH
THE CHANCES OF RAIN HAVE GENERALLY INCREASED SLIGHTLY. THE GREATEST
CHANCE OF RAIN WILL BE ALONG THE COAST NORTH OF HUMBOLDT BAY AND DUE
TO SHOWERS OVER HIGH TERRAIN IN TRINITY COUNTY. ABOUT 80% OF MODELS
SHOW AT LEAST A TRACE OF RAIN IN CRESCENT CITY ON SATURDAY WITH
NEARLY 60% SHOWING EVEN WETTING RAIN. THOSE CHANCES FALL RAPIDLY
FURTHER SOUTH IN EUREKA WHERE THERE IS ONLY A 40% CHANCE OF
MEASURABLE RAIN. RAIN IN THE INTERIOR WOULD LIKELY FALL IN SHOWERS
OVER HIGH TERRAIN, SOME OF WHICH COULD BECOME ISOLATED THUNDERSTORMS
THUNDERSTORMS WOULD BE FAIRLY WET WITH ABOUT A 30% CHANCE WETTING
RAIN ACROSS INTERIOR TRINITY COUNTY. THE CHANCE FOR THUNDERSTORMS IS
LESS SATURDAY (LESS THAN 15%) BUT INCREASES SUNDAY (25% CHANCE) AS
MORE UNSTABLE AIR MOVES IN ALOFT. THERE IS LITTLE TO NO POTENTIAL
FOR WETTING RAIN FOR THE SOUTHERN HALF OF THE AREA. /JHW
AVIATION...(06Z TAFS)
AFTER A THURSDAY AFTERNOON OF BREEZY
NORTHERLY TO NORTHWESTERLY WINDS OVER THE REGION, STRATUS WILL
CONTINUE TO BE SPARSE INTO EARLY FRIDAY MORNING. AS A TROUGH
APPROACHES THE PACIFIC NORTHWEST, THE COASTAL STRATUS WILL SPREAD
INLAND AND DEEPEN THROUGH FRIDAY. IFR TO LIFR CONDITIONS ARE
EXPECTED THROUGH THIS TAF PERIOD AT COASTAL TERMINALS WITH POTENTIAL
FOR SOME COASTAL DRIZZLE. GUSTY NORTHWESTERLY WINDS WILL CONTINUE
THROUGH THE TAF PERIOD FOR LAKE AND SOUTHERN MENDOCINO COUNTIES WITH
VFR CONDITIONS.
MARINE
MODERATE TO STRONG NORTHERLY WINDS WILL CONTINUE TO
DIMINISH INTO FRIDAY MORNING ACROSS THE SOUTHERN WATERS. ISOLATED
GALE CONDITIONS WILL CONTINUE DOWNWIND OF CAPE MENDOCINO INTO
FRIDAY. WINDS AND SEAS WILL GRADUALLY EASE THROUGH FRIDAY, WITH
LIGHT TO MODERATE BREEZES OVER THE WEEKEND.
STEEP, SHORT PERIOD SEAS WILL CONTINUE TO DIMINISH INTO FRIDAY. A
MID-PERIOD SOUTHWESTERLY SWELL AROUND 3 FEET AT 15 SECONDS IS
EXPECTED TO PREVAIL THROUGH FRIDAY, THEN SUBSIDE TO 2 FEET AND
PERSIST THROUGH SUNDAY. IN ADDITION, A MID-PERIOD NORTHWEST SWELL IS
EXPECTED TO BUILD ACROSS THE WATERS SATURDAY AFTERNOON, WILL PEAK TO
AROUND 5-6 FEET AT 10 SECOND LATE SATURDAY NIGHT/EARLY SUNDAY.
FIRE WEATHER
GUSTY NORTHWEST WINDS CONTINUE FRIDAY. THOUGH
MARINE AIR HAS FURTHER COOLED AND MOISTENED CONDITIONS, FIRE
DANGER REMAINS ELEVATED AS FUELS LAG BEHIND. THIS TREND WILL BE
FURTHER REINFORCED WITH SOME GUSTS AS HIGH AS 40 MPH ALONG THE
HIGHEST TERRAIN OF SOUTHERN MENDOCINO AND LAKE COUNTIES.
THANKFULLY, RH WILL ALSO INCREASE WITH RH STRUGGLING TO DROP MUCH
BELOW 30 PERCENT FRIDAY AFTERNOON. COOLER AND MORE MOIST
CONDITIONS WILL PERSIST INTO THIS WEEKEND WITH POTENTIAL FOR LIGHT
WETTING RAIN ALONG THE NORTH COAST (60% CHANCE) AND WET SHOWERS
AND THUNDERSTORMS IN TRINITY COUNTY (30% CHANCE) THOUGH THERE IS
LITTLE CHANCE FOR THE SOUTHERN HALF OF THE AREA. /JHW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 11 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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