304
FXUS66 KEKA 130902
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
202 AM PDT SAT SEP 13 2025
SYNOPSIS
DRY WEATHER WITH SEASONABLY AVERAGE TEMPERATURES
TODAY, BEFORE A PROGRESSIVE TROUGH BRING A CHANCE OF SHOWERS AND A
SLIGHT CHANCE OF THUNDERSTORMS LATE SATURDAY NIGHT THROUGH SUNDAY
MORNING. DRYING AND WARMING TREND RETURNS ON MONDAY AND CONTINUE
THROUGH MID NEXT WEEK.
DISCUSSION
STRATUS AND PATCHES OF FOG ARE BLANKETING THE
NORTHERN COASTAL WATERS AND EXTENDED WELL UP THE ADJACENT RIVER
VALLEYS OVERNIGHT, AND SOUTH OF FORT BRAGG AS WELL. ALTHOUGH,
PROFILERS DATA INDICATE THE MARINE LAYER IS QUITE SHALLOWER THAN
PREVIOUS NIGHT. LOW CLOUDS ARE EXPECTED TO LIFT AND ERODE BACK TO
THE COAST WITH THE DAYTIME HEATING, ALTHOUGH STRATUS NEAR-
COASTAL LOCATIONS ARE EXPECTED TO PERSIST WITH THE GENTLE SEA
BREEZE.
THE SHORTWAVE HIGH PRESSURE CONTINUE SHIFTING EASTWARD TODAY,
WHILE A WEAK H5 TROUGH AND ASSOCIATED COLD FRONT APPROACHES THE
PACIFIC NORTHWEST AND NORTHERN CALIFORNIA. EXPECT ANOTHER DAY
WITH DRY AND NEAR- SEASONAL, OR SEASONABLE, AVERAGE TEMPERATURES.
INLAND HIGH TEMPERATURES ARE FORECAST TO BE SIMILAR TO FRIDAY
WITH HIGHS IN UPPER 70'S TO UPPER 80'S IN THE INTERIOR VALLEYS AND
MID 60'S TO MID 70'S OVER THE FOOTHILLS. COASTAL AREAS WILL
REMAIN UNDER THE MARINE INFLUENCE WITH HIGHS IN THE LOW TO MID
60'S. WINDS WILL LIKELY TO INCREASE FROM THE NORTHWEST THIS
AFTERNOON AND EVENING ALONG THE COAST AND EXPOSED RIDGES, BECOMING
GUSTY AT TIMES, ESPECIALLY FOR MENDOCINO AND LAKE COUNTIES.
SOUTHWEST WINDS ALOFT WILL BRING AN INCREASING MID TO HIGH LEVEL
MOISTURE LATE THIS AFTERNOON AND EVENING AHEAD OF AN APPROACHING
FRONTAL SYSTEM.
THE PROGRESSIVE AFOREMENTIONED TROUGH AND ASSOCIATED COLD FRONT
WILL BRING A CHANCE OF SHOWERS ACROSS THE COAST AND COASTAL
RANGES LATE TONIGHT THROUGH SUNDAY MORNING, MAINLY IN DEL NORTE
AND NORTHERN HUMBOLDT COUNTIES. ALSO, INCREASING INSTABILITY WITH
COLD AIR ALOFT WILL PROMOTE A THREAT OF ISOLATED THUNDERSTORMS
AND BRIEF HEAVY DOWNPOURS LATE TONIGHT INTO EARLY SUNDAY. CONVECTIVE
ALLOWING MODELS (CAMS) INDICATE LOCALIZED STRONG RETURNS OVER
DEL NORTE AND FAR NORTHERN HUMBOLDT LATE TONIGHT. THE HREF MODEL
GUIDANCE INDICATES MAX RAIN RATES OF 0.15 IN/HR TO 0.35 IN/HR LATE
TONIGHT OVER THE SOUTHERLY FACING TERRAIN. OTHERWISE, HOURLY RAIN
RATES WILL RANGE FROM AROUND 0.2 IN OR LESS TODAY. RAINFALL
AMOUNTS ARE FORECAST TO RANGE FROM 0.15 TO 0.30 INCHES THROUGH
LATE SUNDAY MORNING IN DEL NORTE AND FAR NORTHERN HUMBOLDT
COUNTIES. OTHERWISE, DRY WEATHER AND SOME COOLING OF INTERIOR
HIGH TEMPS ARE EXPECTED THROUGH THE DAY ON SUNDAY.
HIGH PRESSURE WILL BEGIN TO BUILDS IN QUICKLY OVER THE REGION ON
SUNDAY IN THE WAKE OF THE FRONT. BREEZY NORTHERLY WINDS ARE
FORECAST TO DEVELOPED OVER MOSTLY COASTAL AREAS AS SURFACE
PRESSURE GRADIENTS TIGHTEN SUNDAY EVENING. NBM PROBABILITIES
INDICATES A 50-80% CHANCE FOR WIND GUSTS GREATER THAN 25 MPH OVER
THE EXPOSED RIDGES AND COASTAL HEADLANDS ON SUNDAY. ALSO, GUSTY
WEST-NORTHWEST WINDS WILL MOST LIKELY DEVELOP THROUGH CHANNELED
TERRAIN IN THE INTERIOR BEHIND THE FRONT SUNDAY AFTERNOON/EVENING.
MONDAY, 850MB WILL BEGIN TO INCREASE AS THE UPPER-LEVEL HEIGHTS
RISES ACROSS THE WEST COAST. THIS WILL BRING A WARMING TREND
EARLY THROUGH MID NEXT WEEK, WITH THE DRIEST AND WARMER DAY ON
TUESDAY. MONDAY NIGHT INTO TUESDAY, BREEZY OFFSHORE WINDS OVER
THE RIDGES ACROSS THE EASTERN PORTION OF THE FORECAST AREA. INTERIOR
VALLEYS ARE FORECAST TO BE IN THE MID TO UPPER 90'S ON TUESDAY
ACROSS THE WARMER LOCATIONS OF TRINITY, LAKE, INTERIOR MENDOCINO,
AND INTERIOR HUMBOLDT COUNTIES. /ZVS
AVIATION...(6Z TAFS)
IFR CEILINGS ARE BEING OBSERVED AT THE
COASTAL TERMINALS, AND STRATUS IS LIKELY TO CONTINUE INTO DAYLIGHT
HOURS. CURRENTLY, IFR CEILINGS ARE FORECAST TO CONTINUE, WITH BRIEF
DIPS DOWN TO LIFR POSSIBLE NEAR SUNRISE. SOME LIFTING IS LIKELY
AFTER SUNRISE, LIKELY TO MVFR BY THE AFTERNOON. SOME SCATTERING IS
POSSIBLE, BUT IT WOULD BE BRIEF BEFORE STRATUS RETURNS OVERNIGHT.
INLAND AREAS WILL REMAIN VFR THROUGH THE NIGHT WITH MOSTLY CLEAR
SKIES AND LIGHT WINDS OUTSIDE THE AFTERNOON. UKI MAY SEE GUSTY
NORTHWEST WINDS IN THE AFTERNOON. JB
MARINE
NORTHERLY WINDS HAVE STARTED TO EASE AS AN UPPER LOW
OVER THE GREAT BASIN WEAKENS AND MOVE EAST. STILL, WINDS ARE LIKELY
TO REMAIN BREEZY THROUGH THE MORNING SOUTH OF CAPE MENDOCINO, BUT
EASE BELOW 15 KTS BY THE AFTERNOON. SHORT PERIOD SEAS REMAIN
ELEVATED TODAY, ESPECIALLY SOUTH OF THE CAPE, AND ARE MIXED WITH A
DECAYING MID-PERIOD NORTHWESTERLY SWELL.
A SHORTWAVE TROUGH WILL BRING A SLIGHT CHANCE FOR THUNDERSTORMS OVER
THE NORTHERN WATERS LATE SATURDAY AND INTO SUNDAY MORNING. HIGH
PRESSURE WILL BEGIN BUILDING BACK IN LATER SUNDAY BEHIND THE TROUGH,
AND THESE TWO FEATURES WILL INCREASE THE NORTHERLY WINDS LATE SUNDAY
THROUGH MONDAY BEFORE BACKING DOWN TUESDAY. STRONGER NORTHERLIES ARE
POSSIBLE MID TO LATE WEEK. JJW/JB
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 11 AM PDT SATURDAY 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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