016
FXUS66 KEKA 090826
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
126 AM PDT SAT AUG 9 2025
SYNOPSIS
HOT AND DRIER WEATHER CONDITIONS EXPECTED THROUGH
TUESDAY. MODERATE TO LOCALIZED MAJOR HEATRISK THIS WEEKEND AND
MONDAY. GUSTY OFFSHORE WINDS ARE EXPECTED OVER THE HIGHER TERRAIN
IN DEL NORTE COUNTY THROUGH THIS MORNING, WITH BREEZY OFFSHORE
FLOW TONIGHT INTO SUNDAY. A GRADUAL COOL DOWN IS EXPECTED BY MID
TO LATE NEXT WEEK.
KEY MESSAGES
* HEAT PEAK THIS WEEKEND WITH MODERATE TO LOCALIZED MAJOR HEATRISK
ACROSS THE INTERIOR.
* HOTTER TEMPERATURES ACROSS THE INTERIOR VALLEYS WILL RESULT IN
MAJOR RISK OF HEAT-RELATED ILLNESS FOR ANYONE WITHOUT EFFECTIVE
COOLING AND/OR ADEQUATE HYDRATE.
* COASTAL AREAS WILL BE A BIT WARMER THIS WEEKEND, THOUGH PEAKS
TODAY WITH HIGHS FROM 65 TO 80 DEGREES IN MOST SPOTS.
* GUSTY OFFSHORE WINDS OVER THE HIGHER TERRAIN IN DEL NORTE COUNTY
THROUGH THIS MORNING AND AGAIN TONIGHT INTO SUNDAY, THOUGH
SLIGHTLY WEAKER FLOW.
DISCUSSION
AN UPPER LEVEL RIDGE WILL CONTINUE TO AMPLIFY
SUBSTANTIALLY OVER THE WRN CONUS DURING THE NEXT 24 HOURS. SKIES ARE
MOSTLY CLEAR ACROSS THE AREA DUE TO A LARGE SCALE SUBSIDENCE AND
LIGHT TO LOCALLY BREEZY OFFSHORE FLOW OVERNIGHT, WITH GUSTY ENE
WINDS AROUND 25 TO 40 MPH OVER THE HIGHER TERRAIN IN DEL NORTE
COUNTY AND WINDIER RIDGES FARTHER NORTHERN PORTION OF HUMBOLDT
COUNTY. OFFSHORE WINDS WILL PERSIST THROUGH THE WEEKEND, BUT
SHOULD DIMINISH SLIGHTLY TONIGHT INTO SUNDAY AS THE
THE LOW- LEVEL AIRMASS ACROSS NRN CA WILL CONTINUE TO WARM TODAY
THROUGH MONDAY (850 MB TEMPERATURES RANGING FROM 25-31C), AND
WHEN COMBINED WITH DAYTIME SUNSHINE WILL YIELD AFTERNOON
TEMPERATURES FROM MID/UPPER 90'S TO LOCALLY 110F. EXCEPT FOR BIG
BAR WHERE A HIGH OF 115F IS FORECAST FOR SUNDAY AND MONDAY.
MODERATE TO LOCALIZED MAJOR HEATRISK IS EXPECTED ACROSS THE
INTERIOR TODAY THROUGH MONDAY. A HEAT ADVISORY REMAIN IN EFFECT
FOR TODAY AND SUNDAY FOR DEL NORTE INTERIOR, NORTHERN HUMBOLDT
INTERIOR, NORTHERN TRINITY AND SOUTHEAST MENDOCINO INTERIOR DUE TO
DUE TO LIMITED OVERNIGHT RELIEF MIN TEMPERATURES IN THE MID/UPPER
60'S AND HIGHS OVER 100. FOR THESE AREAS, THERE IS A MAJOR RISK
OF HEAT- RELATED ILLNESS FOR ANYONE WITHOUT EFFECTIVE COOLING
AND/OR ADEQUATE HYDRATION. THE COASTAL AREAS ARE ALSO EXPECTED TO
WARM UP WITH HIGHS IN THE 70'S BEFORE THE SEA BREEZES DEVELOP WITH
ADJACENT COASTAL AREAS INTO THE 80'S TODAY. THE MARINE LAYER IS
EXPECTED TO RETURN AND SLIGHTLY COOL THE COASTAL AREAS THIS
EVENING THROUGH EARLY NEXT WEEK.
TUESDAY, THE RIDGE BREAK DOWN AND A SHORTWAVE WILL GRADUALLY
SQUEEZE DOWN THE COAST BRINGING A RETURN TO COOLER WEATHER AND
ENHANCED ONSHORE FLOW. HOWEVER, TEMPERATURES ARE EXPECTED TO
REMAIN IN THE UPPER 90'S TO 105 ACROSS THE HOTTEST VALLEYS,
ESPECIALLY IN TRINITY COUNTY.
ENSEMBLE CLUSTERS AND DETERMINISTIC MODEL GUIDANCE SHOWS AN UPPER
LEVEL TROUGH FROM THE NEPAC DRIVE SOUTHWARD ALONG THE COAST ON
WEDNESDAY AND SETTLING OVER THE AREA LATE NEXT WEEK. OTHERWISE,
CLUSTERS ANALYSIS INDICATES DRY WEATHER PREVAILING WITH THE 66% OF
THE MEMBERS, WHILE A 34% INDICATES SOME QPF ALONG THE NORTH COAST
ON FRIDAY. /ZVS
AVIATION...6Z TAFS
SATELLITE IMAGERY TONIGHT IS SHOWING A RARE
SIGHT: COMPLETELY CLEAR SKIES OVER NW CALIFORNIA! OFFSHORE FLOW
ALOFT ALONG WITH A VERY SHALLOW MARINE LAYER WILL CONTINUE TO
PROMOTE MOSTLY CLEAR SKIES INTO THE DAYTIME HOURS, OUTSIDE COASTAL
MENDOCINO. SOME PATCHY FOG IS NOT COMPLETELY OUT OF THE QUESTION
AROUND THE COASTAL TERMINALS IN THE EARLY MORNING HOURS, BUT REMAINS
UNLIKELY. CEC CONTINUES TO SEE GUSTY NORTHERLY WINDS, WHICH MAY PEAK
ABOVE 20 KTS AGAIN IN THE AFTERNOON AND EVENING HOURS. OTHERWISE,
VFR CONDITIONS ARE EXPECTED AT LEAST UNTIL THE EVENING. HEIGHT
DENSITY ISSUES ARE POSSIBLE INLAND AS TEMPERATURES RISE ABOVE TRIPLE
DIGITS.
MARINE
HIGH PRESSURE BUILDING TO THE WEST HAS BROUGHT STRONG
NORTHERLY WINDS TO THE COASTAL WATERS. WINDS ARE STRONGEST IN THE
OUTER WATERS AND IN THE LEE OF CAPE MENDOCINO AND PT. ST. GEORGE.
LOCALIZED AREAS OF GUSTS OVER 40 KTS ARE POSSIBLE IN THE NORTHERN
OUTER WATERS DOWNWIND OF CAPE BLANCO. ELEVATED, STEEP WIND WAVE
DOMINATED SEAS ARE EXPECTED WITH THESE WINDS, AND WILL CONTINUE TO
REMAIN LARGE THROUGH THE WEEKEND WITH HEIGHTS UP TO 15FT@10SECS
POSSIBLE. OUTSIDE OF CAPE MENDOCINO AND PT ST. GEORGE, NEARSHORE
WINDS ARE GENERALLY LIGHTER AT AROUND 10-20 KTS, BUT SEAS WILL BE
STEEP AND ELEVATED AS WIND WAVES PROPAGATE IN FROM THE NORTHWEST.
WINDS HAVE STARTED TO EASE SOUTH OF CAPE MENDOCINO AND PULL AWAY
FROM THE COAST. GALES ARE STILL LIKELY TODAY IN THE NORTHERN OUTER
WATERS AND AROUND PT. ST. GEORGE, HOWEVER ELSEWHERE PEAK GUSTS OF 10-
15 KTS ARE FORECAST. THE MENDOCINO AND SOUTHERN HUMBOLDT COAST IS
FORECAST TO HAVE A SOUTHERLY REVERSAL EARLY THIS MORNING WITH GUSTS
OF 10-20KTS. WINDS AND SEAS EASE FURTHER SUNDAY INTO EARLY NEXT WEEK
AS A LONG/MIDDLE PERIOD SOUTHERLY SWELL MIXES WITH LIGHTER, YET
CONTINUED, NORTHERLY WIND WAVES EARLY TO MID NEXT WEEK.
FIRE WEATHER
GENTLE TO MODERATE BREEZY OFFSHORE FLOW IS
PROMOTING POOR RH RECOVERIES OVERNIGHT WITH GENERALLY 20'S TO
40'S PERCENT ON THE RIDGES, WHILE VALLEY AREAS ARE OVER 50'S
PERCENT...EXCEPT FOR THE NORTHERN VALLEYS IN TRINITY COUNTY WHERE
RECOVERIES IN THE MID 30'S TO LOW 40 ARE OBSERVED. HOT AND DRIER
WEATHER CONDITIONS ARE EXPECTED TODAY THROUGH TUESDAY. VERY DRY
DAYTIME RH'S VALUES IN THE LOW 20'S AND TEENS PERCENT ARE
EXPECTED.
DRY OFFSHORE FLOW (E-NE WINDS) AND ABOVE NORMAL TEMPERATURES ARE
FORECAST TO PERSIST THROUGH THIS WEEKEND. GUSTS FROM 25 TO 40 MPH
ARE EXPECTED THROUGH THIS MORNING OVER THE HIGHER TERRAIN AREAS OF
DEL NORTE AND WINDIER RIDGES OF FAR NORTHERN HUMBOLDT. THE
OFFSHORE WINDS SHOULD DIMINISH THIS EVENING INTO SUNDAY, BUT THE
DOME OF WARM/DRY AIR WILL LIKELY STICK AROUND THROUGH EARLY NEXT
WEEK. WINDS ARE EXPECTED TO BE LIGHT DURING THE DAY, BUT WEST UP
VALLEY WINDS MAY BECOME BREEZY EACH AFTERNOON AND EVENING. DRY
WEATHER WILL CONTINUE NEXT WEEK, BUT WITH A GRADUAL COOLING TREND
AND IMPROVED RH RECOVERIES BY MID TO LATE NEXT WEEK. /ZVS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
HEAT ADVISORY FROM 9 AM TO 10 PM PDT SATURDAY FOR CAZ102-
105-107-110-113.
HEAT ADVISORY FROM 9 AM SUNDAY TO 1 AM PDT MONDAY FOR
CAZ102-105-107-113.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 11 AM PDT SUNDAY FOR PZZ450.
GALE WARNING UNTIL 11 PM PDT SATURDAY FOR PZZ470.
HAZARDOUS SEAS WARNING FROM 11 PM SATURDAY TO 11 AM PDT
SUNDAY FOR PZZ470.
HAZARDOUS SEAS WARNING UNTIL 3 PM PDT SATURDAY 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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