375
FXUS66 KEKA 162014
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
114 PM PDT WED JUL 16 2025
SYNOPSIS
INLAND TEMPERATURES TREND LOW AND REMAIN WARM AND DRY
INTO THE WEEKEND. THE COASTAL STRATUS WILL REMAIN MORE PERSISTENT
OVER THE COASTAL REGIONS, LOWERING THE DAYTIME HIGHS FOR SOME AREAS.
DISCUSSION
UPPER TROUGHING TO THE NORTH THROUGH THE PACIFIC
NORTHWEST IS SUPPRESSING HIGH PRESSURE OVER OUR REGION TODAY. INLAND
TEMPERATURES ARE FORECAST TO BE A FEW DEGREES COOLER THURSDAY AS
THE TROUGH TO THE NORTH SLIGHTLY DEEPENS. THE LOW-LEVEL INVERSION
HAS STRENGTHENED, AND WILL REMAIN STRONG TO MODERATELY STRONG THIS
WEEK. WELL DEFINED COASTAL EDDIES AND STRENGTHENING SOUTHERLY
RETURN FLOW ALONG THE COAST THIS AFTERNOON IS GENERALLY
MAINTAINING THE COASTAL STRATUS. A WEAK SHORTWAVE TROUGH REMAINS
OFF THE COAST WEDNESDAY AND MOST OF THURSDAY. IN RESPONSE, THE
MARINE LAYER WILL FURTHER DEEPEN AND CONTRIBUTE TO MORE DIURNALLY
PRESENT COASTAL STRATUS. THIS WILL HOLD DAYTIME HIGHS DOWN A BIT
WHERE CLEARING DOES NOT OCCUR.
THERE IS A VERY SLIGHT CHANCE (LESS THAN 5%) FOR DRY THUNDERSTORMS
IN NORTHERN TRINITY COUNTY WEDNESDAY AND THURSDAY AFTERNOONS. MODEL
SOUNDINGS SHOW VERY LIMITED ELEVATED INSTABILITY AND AVAILABLE
MOISTURE, WITH A GOOD AMOUNT OF CIN. SOME CUMULUS CLOUDS ARE
OBSERVED ON VISIBLE SATELLITE. INSTABILITY WILL IMPROVE AIR
QUALITY IN THE AFTERNOON, EXCEPT IMMEDIATELY DOWNWIND FROM THE
FIRE. JJW
AVIATION
(18Z TAFS) A LARGE SOUTHERLY REVERSALS ALONG THE NW
COAST TODAY IS CREATING IFR/LIFR CONDITIONS WITH LOW CEILINGS.
SATELLITE IMAGERY SHOWS THESE CLOUDS BEGINNING TO EVAPORATE WITHIN
INLAND RIVER VALLEYS, YET ALONG THE COAST CONDITIONS ARE NOT
EXPECTED TO IMPROVE (AND IF THEY DO IT WILL NOT LAST LONG). LAMP
GUIDANCE SHOWS A LIKELY CHANCE (30-40%) OF IFR CONDITIONS THROUGH
THE DAYLIGHT HOURS TODAY AT KACV AND KCEC, AND THIS CAN BE EXPECTED
ALONG THE MENDOCINO COAST AS WELL. IFR/LIFR CONDITIONS ARE VERY
LIKELY (>80%) TO RETURN TONIGHT TO THE NORTH COAST BEGINNING AROUND
03Z DUE TO LOW CEILINGS RETURNING.
INLAND, VFR CONDITIONS ARE EXPECTED WITH POTENTIAL FOR SMOKEY
VISIBILITIES AS WELL AS DIURNAL WINDS AND LIGHT ELEVATED WINDS
(SOUTHERLY, ~15KT AT 1500FT AGL) IN TRINITY, INTERIOR HUMBOLDT AND
NE MENDOCINO COUNTIES. THE HIRES-ARW MODEL SHOWS FOG (>97% RH)
ENCROACHING OVER THE RUSSIAN AND EEL RIVER VALLEYS AGAIN TONIGHT
AND EARLY TOMORROW MORNING LEADING TO POTENTIAL LIFR CONDITIONS.
MARINE
COASTAL TRAPPED EDDIES ARE PRESENT IN BOTH THE NORTHERN
AND SOUTHERN INNER WATERS THIS MORNING AS SEEN BY SATELLITE IMAGERY.
EXPECT LIGHT SOUTHERLY BREEZES CLOSE TO SHORE WITH LOW CLOUDS AND
POSSIBLE FOG/DRIZZLE. WITH THESE CALMER WINDS, THE STEEP SEAS ARE
FORECAST TO CALM THROUGH TODAY. OVER THE NEXT FEW DAYS, MODERATE
BREEZES ARE EXPECTED THROUGH FRIDAY. STRATUS, DRIZZLE, AND FOG ARE
EXPECTED AS WELL WITH POTENTIALLY DEGRADED VISIBILITIES, ESPECIALLY
AT NIGHTTIME AND IN THE EARLY MORNINGS.
FIRE WEATHER
THERE IS A VERY SLIGHT CHANCE (LESS THAN 5%) FOR
DRY THUNDERSTORMS IN NORTHERN TRINITY COUNTY WEDNESDAY AND THURSDAY
AFTERNOONS. MODEL SOUNDINGS SHOW VERY LIMITED ELEVATED
INSTABILITY AND AVAILABLE MOISTURE, ALONG WITH A GOOD AMOUNT OF
CIN. SOME CUMULUS CLOUDS ARE OBSERVED ON VISIBLE SATELLITE. THE
INSTABILITY WILL IMPROVE VENTILATION. THE DEEPENED MARINE LAYER
WILL CONTINUE TO MAINTAIN MARINE INFLUENCE FARTHER INLAND FROM THE
COAST. FURTHER DEEPENING IS LIKELY THROUGH THURSDAY. A WEAK
SHORTWAVE TROUGH WILL INCREASE SOUTHERLY TO SOUTHWESTERLY WINDS
LOCALLY WEDNESDAY AND THURSDAY AFTERNOONS IN LAKE AND SOUTHERN
MENDOCINO COUNTIES. INLAND TEMPERATURES WILL INCH SLIGHLTY HIGHER
LATE THIS WEEK WHILE CONDITIONS REMAIN WARM AND DRY. MINIMUM RH
WILL DROP INTO THE LOW 20S TO MID TEENS WITH SOME INCREASING
WESTERLY WINDS THROUGH SATURDAY BEFORE TRENDING HIGHER SUNDAY AND
INTO NEXT WEEK. JJW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
NONE.
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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