499
FXUS66 KEKA 192132
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
232 PM PDT THU MAR 19 2026
SYNOPSIS
UNSEASONABLE WARMTH WITH WIDESPREAD MINOR HEAT RISK IN
THE INTERIOR IS FORECAST TO ABATE THIS WEEKEND INTO EARLY NEXT WEEK.
COASTAL NORTHERLIES WILL INCREASE ON SATURDAY AFTER PASSAGE OF A
FRONT. NEXT CHANCE FOR RAIN IS EXPECTED TUESDAY INTO WEDNESDAY.
DISCUSSION
A MASSIVE 500MB HEIGHT ANOMALY (GPH 594DM) CENTERED
OVER THE SW U.S. AND EXTENDING NW OVER OUR FORECAST AREA CONTINUED
TO RESULT IN MAX TEMPERATURES WELL ABOVE MID MARCH NORMALS (30-YEAR
AVERAGE) TODAY IN THE INTERIOR. HIGH TEMPERATURES ARE FORECAST TO
PEAK INTO THE MID 80S AND LOWER 90S IN MENDOCINO AND LAKE COUNTIES
TODAY. DEL NORTE, HUMBOLDT AND TRINITY WILL MOST LIKELY PEAK IN
THE MID 70S TO UPPER 80'S AGAIN THIS AFTERNOON. THIS IS 20F OR
MORE ABOVE MID MARCH AVERAGES. OVERNIGHT LOW TEMPERATURES HAVE
BEEN GENERALLY COOL UNDER THE DRY AIRMASS AND LIGHT WIND REGIME IN
MANY OF THE INTERIOR VALLEYS. A FEW OF THE COLDER VALLEYS IN OUR
FORECAST AREA HAVE BEEN DIPPING DOWN INTO LOWER TO MID 30'S AFTER
WARMING INTO THE LOWER TO MID 80'S. AS RESULT THE HEAT RISK IS
FORECAST TO REMAIN MINOR, BUT MAY STILL IMPACT THOSE EXTREMELY
SENSITIVE TO HEAT AND/OR HAVE NO WAY TO KEEP COOL. MODERATE HEAT
RISK IS FORECAST FOR MOSTLY LAKE COUNTY AGAIN ON FRIDAY WHERE
OVERNIGHT LOW TEMPERATURES HAVE BEEN WARMER, IN THE 50S TO MID
60S, FOR THE HIGHER TERRAIN AND WITHIN THE THERMAL BELT. THE ABOVE
NORMAL DAYTIME WARMTH IS FORECAST TO CONTINUE FOR ONE MORE DAY,
FRIDAY, FOR THE MENDOCINO AND LAKE, WHILE DAYTIME HIGHS DIMINISH
SOME FOR THE NORTHERN ZONES IN RESPONSE TO AN OFFSHORE TROUGH.
THIS TROUGH WILL KNOCK DOWN 500MB HEIGHTS AND INDUCE AN ONSHORE
FLOW FOR THE REGION. TEMPERATURES WILL COOL DOWN MORE SUBSTANTIALLY
ON SATURDAY AFTER SLIGHT AIR MASS COOLING WITH A FRONT, AIDED BY
GUSTY NORTHERLIES IN THE AFTERNOON. HIGHS ARE STILL FORECAST TO
REMAIN ABOVE NORMAL ON SUNDAY AS OFFSHORE FLOW RE-EMERGES AND
AREAS OF MINOR HEAT RISK SPRING UP AGAIN IN THE INTERIOR; MAINLY
FOR LAKE, TRINITY AND INTERIOR MENDOCINO.
COASTAL AREAS REMAINED MUCH COOLER TODAY EVEN UNDER GREATER
SUNSHINE. SATELLITE SHOWED STRATUS AND FOG JUST OFFSHORE OVER
THE COASTAL WATERS THIS AFTERNOON. WITH LESS STRATUS AND FOG
COMPARED TO YESTERDAY, TEMPERATURES WERE WARMER. AS OF 2PM, TEMPS
WERE IN THE LOWER 60'S ALONG THE NORTH COAST. JUST A FEW MILES
FURTHER INLAND IT WAS MUCH WARMER, IN THE LOWER 70S. THE MASS OF
STRATUS AND FOG OFFSHORE WILL LINGER NEAR THE COASTLINE TONIGHT
AND FRIDAY AND MAY PUSH INTO THE ADJACENT RIVER VALLEYS. PATCHES
OF FOG WITH VSBY 1/4SM OR LESS WILL BE A DISTINCT POSSIBILITY
AGAIN. FOG WAS LOCALLY DENSE AROUND HUMBOLDT BAY THIS MORNING, BUT
NOT WIDESPREAD. OFFSHORE WINDS CLEARED MOST OF THE FOG OUT BY MID
MORNING THU. ONSHORE BREEZES THIS AFTERNOON WILL LIKELY DRAW IN
THE COOL-DAMP MARINE AIR AND FOG MAY ONCE AGAIN POSE A HAZARD TO
NAVIGATION.
BROAD FLAT RIDING WITH ABOVE NORMAL 500MB HEIGHTS WILL DOMINATE
THE WEATHER SCENE FOR NORTHWEST CALIFORNIA THIS WEEKEND THROUGH
EARLY NEXT WEEK. THIS WILL ENSURE DRY WEATHER WITH ABOVE NORMAL
DAYTIME HIGH TEMPERATURES. PATCHES OF MIST AND COASTAL DRIZZLE
WILL BE POSSIBLE WITH A DECAYING FRONT EARLY SAT, OTHERWISE THE
NEXT FORMIDABLE CHANCE FOR RAIN WILL ARRIVE TUE-WED NEXT WEEK.
DETERMINISTIC MODELS CONTINUE TO VARY WIDELY WITH TIMING AND
AMOUNTS. NBM HAS QUITE THE 24-HR SPREAD TOO SO STAY TUNED FOR
UPDATES AND MORE DETAILS.
RIDGING SPRINGS BACK AROUND MID NEXT WEEK AFTER OUR BRIEF SPAT OF
RAIN TUE OR WED. GENERALLY DRY CONDITIONS WITH ABOVE NORMAL INTERIOR
HIGH TEMPS ARE EXPECTED. OVERNIGHT LOW TEMPS MAY COOL DOWN MID OR
LATE NEXT WEEK FOR PERHAPS LOW END FROST FREEZE CONCERNS.
AVIATION
COASTAL STRATUS WITH PATCHY DENSE FOG, ESPECIALLY
AROUND HUMBOLDT BAY, ERODED AWAY FROM THE COAST BY MID TO LATE
MORNING. VFR CONDITIONS ARE EXPECTED TO PREVAIL UNTIL LATER THIS
EVENING. WHILE MOST TERMINALS IN THE INTERIOR ARE EXPECTED TO REMAIN
VFR THROUGH THE TAF PERIOD, COASTAL STRATUS WILL ONCE AGAIN AFFECT
COASTAL TERMINALS THROUGH THE OVERNIGHT HOURS. THE HIGH PRESSURE
SYSTEM OVER THE REGION WILL WEAKEN THROUGH THE NIGHT, WHILE A
SHORTWAVE TROUGH APPROACHES THE PACIFIC NW. THIS WILL AID IN
DEEPENING THE COASTAL STRATUS WHICH WILL LEAD TO GREATER COVERAGE
INTO TOMORROW MORNING. THIS WILL MOST LIKELY MEAN MORE WIDESPREAD
MVFR/IFR CONDITIONS A BIT FURTHER INLAND AND LESS OF A CHANCE FOR
AREAS OF DENSE FOG. /JLW
MARINE
AS HIGH PRESSURE GRADUALLY PUSHES EAST, THE PRESSURE
GRADIENT OVER THE AREA HAS REACHED IT WEAKEST, ALLOWING FOR GENTLE
TO MOSTLY CALM NORTH WINDS THROUGH TODAY GENERALLY BELOW 15 KTS. AS
HIGH PRESSURE FINALLY BREAKS DOWN, STRONGER WINDS WILL BEGIN TO
RETURN FIRST TO THE SOUTHERN WATERS FRIDAY AFTERNOON WITH GUSTS NEAR
25 KTS. CONDITIONS WILL BUILD TO NEAR GALE DURING THE DAY SATURDAY
IN THE OUTER WATERS, WITH STRONG WINDS OVER 25KTS PUSHING EVEN INTO
THE INNER WATERS SATURDAY AFTERNOON AND EVENING.
CALMER WINDS WILL GENERALLY LIMIT ANY MEANINGFUL SHORT PERIOD SEAS
THROUGH TODAY. THAT SAID, A MINOR, LONG PERIOD SOUTHERLY SWELL AND
MODEST MID PERIOD WESTERLY SWELL COMBINE TO CREATE AT LEAST SOME
SEAS UP TO 6 FEET THROUGH TONIGHT. STEEPER SHORT PERIOD SEAS WILL
RETURN FRIDAY AND INTO THE WEEKEND WITH THE WIND ALLOWING FOR WAVE
HEIGHTS IN EXCESS OF 10 FEET BY SATURDAY. /JHW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 11 PM FRIDAY TO 3 PM PDT SATURDAY
FOR PZZ455.
SMALL CRAFT ADVISORY FROM 3 AM TO 3 PM PDT SATURDAY FOR
PZZ470.
SMALL CRAFT ADVISORY FROM 5 PM FRIDAY TO 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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