Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
109 FXUS66 KEKA 180702 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1202 AM PDT Mon Aug 18 2025 .SYNOPSIS...Warmer trends and the possiblility of heat risk by the end of the week are to be expected as ridging sets in and high pressure becomes the prevailing trend. A gradual drying and warming trend will develop this week, with further warming late in the week along with low RH. && .DISCUSSION...Conditions that brought light precipitation over the weekend will transition as a ridging pattern up stream, sets in by mid to late week. Stratus is becoming less resilient as the evenings are showing improvements which will continue as high pressure and subsidence build. Chances for fog are lower tonight, with less coverage expected. Moisture and instability mostly depart to start the work week Monday. This will also mark the start of a gradual warming trend. A shortwave perturbation will clip the northern region Wednesday, but is expected to have little impacts other suppressing the greater inevitable warmup. Beyond the passing of the shortwave, temperatures will indeed further warm late in the week. Probability for isolated warmer valleys to exceed 100 increases Thursday. Chances for temperatures over 100 are highest Friday (75%) for the interior valleys. Chances begin slowly dropping thereafter with a weak signal from clusters of some troughing influence, but the heat may linger longer through the weekend. There are hints of some monsoonal moisture getting pulled in from the SE by the weekend. This would increase chances for thunderstorms, but the quality of moisture and instability look poor at this time. /JJW /EYS && .AVIATION...(06Z TAFs)...IFR/LIFR conditions continue to redevelop along the coast through early Monday morning with low clouds and visibility in FG/mist. Winds have become very light along the coast with periods of a southerly reversal wind along the Del Norte Coast. General cloudiness is expected for the interior of Humboldt, Trinity, and Del Norte counties, with mostly VFR conditions still. VFR conditions are forecast for interior Mendocino and Lake counties with the potential for some marine stratus creeping up the Russian River Valley into KUKI early Monday morning. && .MARINE...Light to moderate breezes are forecast to continue into Monday. A NW swell around 4 to 6 feet at around 10 seconds will persist, before slowly subsiding through mid next week. Relatively calm conditions with light to gentle breezes and low seas are expected on Monday. Northerly winds begin to slowly increase on Tuesday as a surface high pressure builds in, especially south of Cape Mendocino. Increasing winds will spread northward and continue strengthening by mid to late week as a thermal trough develops near the coast. This will result in moderate to strong breezes and steep seas, especially across the outer waters. /ZVS && .FIRE WEATHER...Low RH values and the return of high temperatures by the middle of the week and into the weekend. A gradual warming and drying trend will start Monday, with the driest conditions likely reached by the weekend. && .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. Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png