Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
708 FXUS66 KEKA 281137 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 437 AM PDT Thu Aug 28 2025 .UPDATE....AVIATION...(12Z TAFs)...Coastal stratus continues leading to IFR categories along the NW California coastline. A shortwave trof aloft is deepening the marine layer, keeping ceilings at 600-800ft AGL at coastal observation points. The ceilings may drop some towards sunrise as the lower atmosphere cools to its minimum temperature, but LIFR conditions are not expected to last too long, if at all. Potential short-term clearing is possible as stratus ebbs and flows along the coast before settling in again this evening. Inland, VFR is expected with terrain driven, potentially gusty winds Smoke is forecast to flow out of the forecast area through the day. && .PREV DISCUSSION... /issued 1210 AM PDT Thu Aug 28 2025/ SYNOPSIS...Temperatures remain around seasonal norms through at least early next week. Dry conditions will persist with no precipitation expected. Coastal cloudcover will remain relatively persistent through this week. DISCUSSION...A couple thunderstorms grazed far NE Trinity County this afternoon, but with departure on monsoonal moisture, the threat for thunderstorms has ended. A deep marine layer and a moderately strong inversion continues to limit clearing and full sunshine along the coast, mainly around Humboldt Bay and northward. A similar setup is expected Thursday. The deep marine layer will limit lower level stratus and fog visibility. There are indications the inversion will weaken by Friday, allowing for better daytime coastal clearing through the weekend. An upper low will very slowly graze the coast late in the week and through the weekend on its way northeast. There will be instability and shower/thunderstorm activity associated with it, but models keep it well offshore as it passes. A light shower may graze closer to the Del Norte border. Current probabilities for even a trace of rainfall are zero for the forecast area. The low will then undergo some unusual steering flow, potentially retrograding back west early next week. This could mean a rebound of upper heights and a slight warmup. The majority of ensemble members (63%) and cluster members favor this solution, but if shortwave troughing forms in our region south of the ridge, monsoonal moisture and a thunderstorm threat will redevelop. AVIATION...Stratus is in place along the coast north of Ferndale. This may expand some, possibly returning to the Mendocino coast before sunrise. The CIGS may drop some towards sunrise, but LIFR conditions are not expected to last too long. This afternoon winds are expected to generally be less than 10 kt. CIGS are expected to lift along the coast although the HREF shows clouds generally lingering at the coastal airports with a few breaks possible. Tonight stratus is expected to return and for now have gone with persistence and kept it IFR. MKK MARINE...Light southerly winds are expected through Friday, however there may be some varying directions as some little weak fronts move through. Overall winds are expected to remain under 10 kt. Waves continue to diminish as well with waves generally around 3 to 5 feet. This will be a combination of a northwest wave of 3 feet at 8 seconds and couple of south to southwest waves. These are generally around 2 to 3 feet at 17 seconds, although there may also be some energy at 12 seconds. These conditions are expected to continue through Friday. Friday night and into Saturday high pressure is expected to start building into the area and bring northerly winds. This is expected to begin in the southern waters and expand north through the weekend. Winds of 15 to 25 kt are expected, but at this point it doesn`t look like there will be gales. The waves are generally expected to wind driven, although the small southerly swell may continue as well. MKK FIRE WEATHER...Minimum RH will continue to lower Thursday, down to the mid to low teens for the far interior. Winds will mostly be diurnally and terrain driven. A passing shortwave will cause a slight westerly to southerly wind surge thursday afternoon. This will be the driest day, but overnight recoveries will be 30 to 50%. The marine layer is relatively deep, and this is allowing for further inland push of marine influenced air. Minimum RH and recoveries will then trend higher through the weekend. Stronger westerly afternoon wind surges are forecast Friday and Saturday for Lake County where wind gusts over 20 mph are probable (50 to 62%). 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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