026
FXUS66 KEKA 192017
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
117 PM PDT MON MAY 19 2025
SYNOPSIS
THE HUMBOLDT AND DEL NORTE COASTS WILL CONTINUE TO SEE
MOSTLY CLOUDY SKIES THIS AFTERNOON WITH A FEW SHOWERS POSSIBLE AS
WELL. OTHERWISE CLEAR SKIES ARE EXPECTED. TUESDAY AND WEDNESDAY
HIGH PRESSURE BUILDS IN BRINGING CLEAR SKIES AND WARMING
TEMPERATURES. LATE IN THE WEEK COOLER TEMPERATURES AND LIGHT
POSSIBLE RAIN.
DISCUSSION
A VERY WEAK FRONTAL BOUNDARY IS APPROACHING THE
COAST THIS AFTERNOON. THIS WILL MAINLY KEEP CLOUDS IN PLACE, BUT
MAY ALSO BRING A FEW ISOLATED SHOWERS TO DEL NORTE COUNTY AND THE
HIGHER TERRAIN OF HUMBOLDT COUNTY. ANY RAINFALL IS EXPECTED TO BE
LESS THAN A TENTH OF AN INCH AND MORE LIKELY A TRACE TO A FEW
HUNDREDS. THERE IS THE POTENTIAL FOR SOME FROST IN THE COLDEST
VALLEYS OF TRINITY COUNTY, BUT AT THIS POINT IT LOOKS LIKE CLOUDS
MAY MOVE ACROSS THE KEEP THIS FROM OCCURRING.
TUESDAY CLEARING SKIES ARE EXPECTED AS HIGH PRESSURE BUILDS IN.
HIGHS ARE EXPECTED TO BE IN THE UPPER 70S TO LOW 80S ON TUESDAY.
CONTINUED WARMING AND DRY IS EXPECTED ON WEDNESDAY WITH HIGHS
LIKELY TO BE NEAR 90 IN MENDOCINO AND LAKE COUNTIES. OVERNIGHT
LOWS WILL CONTINUE TO DROP INTO THE UPPER 40S TO LOW 50S AND THIS
WILL REDUCE THE HEAT RISK.
WEDNESDAY NIGHT AND THURSDAY FLOW BECOMES MORE ZONAL. SOME OF THE
MODELS SHOW A SHORTWAVE MOVING THROUGH AND DROPPING THE HEIGHTS
MORE BY FRIDAY AND INTO THE WEEKEND. THE ENSEMBLE CLUSTERS
HIGHLIGHT SOME OF THE UNCERTAINTY WITH THE TIMING OF THESE
SHORTWAVES. THE BETTER CHANCES FOR RAIN AND A DEEPER TROUGH START
SUNDAY NIGHT AND MONDAY. THE NBM IS SHOWING A 30 TO 50 PERCENT
PROBABLY OF A TENTH OF AN INCH OF RAIN IN DEL NORTE COUNTY WITH
LOWER PROBABILITIES FARTHER SOUTH. MKK
AVIATION
WEAKENING FRONTAL BOUNDARY IS FORECAST TO PUSH ONSHORE
THIS AFTERNOON AND EVENING. SHALLOW MOIST AIR AND STRONGER N-NW
WINDS BEHIND THE FRONT WILL PROBABLY (60% CHANCE) RESULT IN IFR AND
POSSIBLY (20% CHANCE) LIFR CONDITIONS AT COASTAL TERMINALS THIS
EVENING. NORTHERLIES INCREASE LATER TONIGHT INTO TUESDAY MORNING AND
SHOULD SCOUR OUT THE LOW LEVEL MOISTURE OVER COASTAL AERODROMES.
LINGERING MVFR CEILINGS ARE STILL LIKELY (60% CHANCE) TUE AM,
HOWEVER. OTHERWISE, VFR CONDITIONS WITH GUSTY NORTH TO NORTHWESTERLY
WINDS ARE FORECAST FOR KUKI. THERE IS A 50% CHANCE FOR LOW LEVEL
TURBULENCE AND/OR LOW LEVEL SPEED SHEAR UKI AND VICINITY OVERNIGHT
AS SURFACE GUSTINESS DECOUPLES. GUSTY NORTHERLY AND NORTHWESTERLY
WINDS AND SHALLOW LOW LEVEL TURBULENCE AND/OR LOW LEVEL SPEED SHEAR
INCREASES THROUGHOUT DURING THE DAY ON TUESDAY. DB
MARINE
MARINE CONDITIONS ARE FORECAST TO DETERIORATE ON TUESDAY
AS NORTHERLY WINDS AND STEEP WAVES INCREASE THROUGH THE DAY. HREF
PROBABILISTIC GUIDANCE CONTINUES TO SUPPORT PEAK GUSTS TO 35-40KT IN
THE LEE OF CAPE MENDOCINO AS AN EXPANSION FAN GROWS THROUGH THE DAY
ON TUESDAY AND REACHES MAXIMUM COVERAGE BY LATE AFTERNOON INTO THE
EVENING HOURS. A SMALLER AND SHORTER DURATION EXPANSION FAN REGION
ALSO DEVELOPS IN THE LATE AFTERNOON ACROSS THE NORTHERN WATERS,
AROUND AND JUST DOWNWIND OF PT ST GEORGE. COVERAGE APPEARS MINIMAL
FOR A GALE WARNING FOR THE NORTHERN WATERS. FOR NOW WILL HOIST
ADVISORIES FOR SMALL CRAFT GIVEN THE RAMP UP OF STEEP NORTHERLY
WAVES OF 6-8 FT ON TOP OF AN INCOMING NW SWELL OF 8-10 FT. COMBINED
SEAS (SIGNIFICANT WAVE HEIGHTS) ARE FORECAST TO REACH 10-13 FEET,
HIGHEST SOUTH OF CAPE MENDO, BY TUE AFTERNOON AND EVENING. MARINE
CONDITIONS ARE FORECAST TO EASE UP TOWARD THE END OF THE WEEK,
EXCEPT SOUTH OF CAPE MENDOCINO WHERE WIND AND SEAS WILL LIKELY
REMAIN HAZARDOUS FOR SMALL CRAFT AND INEXPERIENCED MARINERS. DB
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
GALE WARNING FROM 2 PM TO 11 PM PDT TUESDAY FOR PZZ475.
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