012
FXUS66 KEKA 262214
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
314 PM PDT SAT APR 26 2025
SYNOPSIS
NUMEROUS SHOWERS THROUGH THIS EVENING, WITH LINGERING
SHOWERS INTO SUNDAY MORNING. BREEZY NORTHWEST WINDS WILL DEVELOP
ALONG THE COAST AND EXPOSED RIDGES THIS AFTERNOON AND SUNDAY
AFTERNOON HOURS. DRY AND WARMING TREND SUNDAY THROUGH MID NEXT
WEEK. CHANCES OF PRECIPITATION RETURN LATE NEXT WEEK.
DISCUSSION
RADAR DOPPLER DEPICTS NUMEROUS SHOWERS STREAMING
SOUTHWEST ACROSS NORTHWEST CALIFORNIA THIS AFTERNOON. THESE
SHOWERS WILL CONTINUE TO ROTATE AROUND AN UPPER LEVEL TROUGH
CENTER OVER CENTRAL CALIFORNIA. PRECIPITATION WILL GRADUALLY TO
TAPPER OFF FROM NORTH TO SOUTH LATE THIS AFTERNOON AND EVENING AS
THE TROUGH EJECT THE AREA.
MEANWHILE, BREEZY NORTHWEST WINDS HAVE BEEN DEVELOPING ALONG THE
NORTH COAST AS A SURFACE HIGH PRESSURE BEGINS TO BUILD IN THE WAKE
OF THE TROUGH, TIGHTENING THE PRESSURE GRADIENT. THESE WINDS ARE
EXPECTED TO SPREAD SOUTH ALONG THE MENDOCINO COAST EARLY THIS
EVENING. EXPECT GUSTS FROM 25 TO 35 MPH ARE ALONG THE COASTAL
HEADLANDS AND EXPOSED RIDGES, WITH LOCALLY UP TO 40 MPH POSSIBLE
OVER THE MORE PROMINENT EXPOSED TERRAIN.
SUNDAY, SOME LINGERING SHOWERS ARE POSSIBLE INTO EARLY MORNING.
FOLLOWED BY DRY WEATHER AND WARMING TREND AS A H5 HIGH PRESSURE
BEGIN TO BUILDS IN DOWNSTREAM IN THE WAKE OF THE TROUGH. HOWEVER,
SOME ISOLATED SHOWERS ARE POSSIBLE SUNDAY AFTERNOON ACROSS THE
INTERIOR WITH THE DIURNAL HEATING AND LINGERING LOW LEVEL
MOISTURE, ESPECIALLY IN LAKE COUNTY. BREEZY NORTHWEST WINDS WILL
REDEVELOPED ALONG THE COASTAL HEADLANDS AND EXPOSED RIDGES SUNDAY
AFTERNOON. HREF WIND GUSTS MEAN SUGGEST SIMILAR CONDITIONS AS
SATURDAY, WITH GUSTS GENERALLY FROM 25-35 MPH. INLAND AREAS ARE
EXPECTED TO SEE HIGHS FROM MID 50'S TO MID 60S. AREAS OF VALLEY
FOG ARE EXPECTED TO DEVELOP SUNDAY NIGHT INTO MONDAY.
MONDAY, EXPECT MOSTLY SUNNY WITH DRY AND WARMER TEMPERATURES.
INLAND HIGH TEMPERATURES IN THE MID 60'S TO MID 70'S. COASTAL
AREAS MAY SEE HIGH TEMPERATURES UP TO LOW 60'S, BEFORE SEA BREEZES
DEVELOPS BY THE AFTERNOON. /ZVS
LONG-TERM...TUESDAY-SATURDAY
24-HOUR CLUSTER MEANS CONTINUE TO
INDICATE ABOVE NORMAL 500MB HEIGHTS WITH RIDGING OVER THE PAC NW
TUESDAY THROUGH THURSDAY. GREATER VARIANCE AND DEPARTURES FROM THE
GRAND ENSEMBLE MEAN START TO ARISE AS EARLY THU WITH SUBTLE
DIFFERENCES IN THE EASTWARD PROGRESSION OF THE 500MB HEIGHT
ANOMALY. ABOUT 30% OF ENSEMBLE MEMBERS INDICATE A SLIGHLTY WETTER
OUTCOME ON THU, WITH SHOWERS MOSTLY OVER THE MOUNTAINS AND PERHAPS
A PUSH OF MARINE MOISTURE AND LOW CLOUDS. OTHERWISE, DRY WEATHER
WITH ABOVE NORMAL HIGH TEMPERATURES IN THE INTERIOR IS THE MOST
LIKELY OUTCOME TUESDAY-THURSDAY. BY DAY 6, FRIDAY MAY 2, ALL
CLUSTER MEANS DEPICT ANOTHER 500 TROUGH DIGGING OFFSHORE OR OVER
THE FORECAST AREA. THERE ARE CONSIDERABLE DIFFERENCES WITH THE
DEPTH AND PROGRESSION OF THE SPLITTING TROUGH. POTENTIAL FOR MORE
WET AND UNSETTLED WEATHER INCREASES FRIDAY-SATURDAY WITH NBM
PROBABILITIES FOR OVER 0.25IN OF RAIN IN 24 HOURS INCREASING TO 30
TO 50% FOR DEL NORTE, HUMBODLT AND TRINTY COUNTIES. CHANCES ARE
ONLY 10-25% FOR MENDO AND LAKE. THUNDER CHANCES ARE MORE ELUSIVE
AND UNCERTAIN, BUT NBM HAS A 13% CHANCE IN TRINITY FRI-SAT. ONLY
ABOUT 18-26% OF MEMBERS WERE DECISIVELY WETTER THAN THE GRAND
ENSEMBLE MEAN BY SATURDAY MAY 3. ALSO, OUR MID WEEK WARM UP WILL
COME TO A HALT LATE NEXT WEEK (FRI) INTO NEXT WEEKEND. TROUGH
EVOLUTION BECOMES MUCH MORE UNCERTAIN BY SUNDAY. THE TROUGH MAY
END UP CLOSING OFF INTO A CUT- OFF LOW OVER THE DESERT SW AND SRN
GREAT BASIN BY DAY 8 (SUNDAY MAY 4). A FASTER PROGRESSION WITH
STRONGER RIDGING OFFSHORE SUGGESTS A GUSTY NORTHERLY WIND SCENARIO
FOR OUR FORECAST AREA BY END OF DAY 8 (SUNDAY MAY 4). A SLOWER
PROGRESSION WITH WRAP AROUND MOISTURE SUGGESTS A WETTER SCENARIO
INTO DAY 8. STAY TUNED FOR UPDATES. /DB
AVIATION
MULTI-LAYERED CLOUD COVER, MOIST AIR AND AREAS OF RAIN
CONTINUED TO WRAP AROUND A VIGOROUS UPPER LEVEL LOW TRACKING
EASTWARD OVER CENTRAL CALIFORNIA THIS AFTERNOON. MOSTLY MVFR
CONDITIONS HAVE BEEN OCCURRING WITH PERIODS OF IFR AT COASTAL
AERODROMES IN LIGHT RAIN. GUSTY NORTHERLIES HAVE BEEN DEVELOPING
OVER COASTAL AERODROMES THIS AFTERNOON. NORTHERLIES WILL CONTINUE TO
STRENGTHEN THIS EVENING AND GUSTY CONDITIONS MAY CONTINUE INTO THE
OVERNIGHT HOURS AS THE LOW TRACKS INTO THE GREAT BASIN AND HIGH
PRESSURE OFFSHORE BUILDS EASTWARD. PROBABILITY FOR LOW LEVEL WIND
SHEAR OR LOW LEVEL TURBULENCE INCREASES TO 40-50% JUST OUTSIDE THE
VICINITY OF KACV THIS EVENING AND MAY PERSISTS TIL 15Z SUNDAY.
GREATER PROBABILITY FOR SHEAR AND SHALLOW MOUNTAIN WAVE TURBULENCE
INCREASES TO 80% OVER THE COASTAL MOUNTAINS, PARTICULARLY THE KING
RANGE, AS LOW LEVEL NORTHERLIES RAMP UP THIS EVENING AND OVERNIGHT.
TREND IS FOR SHALLOW MOIST LAYERS TO DIMINISH THROUGH THE DAY ON
SUNDAY, HOWEVER GUSTY NORTHERLY WINDS ARE FORECAST TO QUICKLY PICK
UP AGAIN WITH DIURNAL HEATING. DB
MARINE
NORTHERLIES ARE FORECAST TO INCREASE LATE THIS AFTERNOON
INTO THIS EVENING IN THE NW QUADRANT OF A BROAD LOW PRESSURE SYSTEM
CENTERED OVER CENTRAL CAL. HIGH RESOLUTION MODELS AND HREF ENSEMBLE
PROBABILITIES INDICATE WIND GUSTS TO 35-40KT OVER A MUCH LARGER AREA
THAN PREVIOUS MODEL ITERATIONS. A GALE WARNING FOR GUST > 34 KT HAS
BEEN HOISTED FOR THE NORTHERN OUTER WATERS. COVERAGE FOR THE
NORTHERN INNERS IS MUCH MORE UNCERTAIN, THOUGH NORTH OF ORICK GALE
GUSTS ARE PROBABLE THIS EVENING AND OVERNIGHT. STEEP WAVES FROM 9
TO 11 FT AT 9 SECONDS WILL ALSO BUILD THIS EVENING AND WILL BE
BORDERLINE FOR A HAZARDOUS SEAS WARNING FOR THE NORTHERN INNERS.
ALSO COVERAGE FOR A GALE WARNING IN THE SOUTHERN WATERS IS CLOSE
TO 50% OR MORE, BUT OPTED TO HOIST A HAZARDOUS SEAS WARNING FOR
WAVES OF 11 FT AT 9 SECONDS. NEAR GALES AND VERY STEEP WAVES WILL
PROBABLY CONTINUE SOUTH OF CAPE MENDOCINO ON SUNDAY AS WELL.
SPRING TIME NORTHERLIES FEATURING LOCALIZED RIBBONS OF STRONG
WINDS (>34KT) AND STEEP WAVES WILL PERSIST INTO EARLY NEXT WEEK.
DB
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PZZ450.
HAZARDOUS SEAS WARNING FROM 9 PM THIS EVENING TO 9 AM PDT
SUNDAY FOR PZZ450.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PZZ455.
SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ470.
GALE WARNING UNTIL 3 AM PDT SUNDAY FOR PZZ470.
HAZARDOUS SEAS WARNING FROM 3 AM TO 9 AM PDT SUNDAY FOR
PZZ470.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PZZ475.
HAZARDOUS SEAS WARNING FROM 9 PM THIS EVENING TO 9 PM PDT
SUNDAY FOR PZZ475.
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