Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
275 FXUS66 KEKA 122149 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 249 PM PDT Wed Jun 12 2024 .SYNOPSIS...Cooler temperatures will be the trend starting Thursday with more substantial cooling over the weekend. Northwesterly winds strengthen in the interior with strong gusts Thursday night into Friday morning. && .DISCUSSION...Dry weather continues with temperatures in the interior reaching the High 80s to low 90s, with a few areas reaching closer to the upper 90s and low 100s. Trinity county temperatures look to be their highest near Big Bar and Weaverville, around 96. Mendocino interior has a few higher temperatures at Potter Valley and Ukiah at 99 and 100 respectively. Lake county will approach a moderate Heat Risk in the southern and eastern areas bordering Colusa, Yolo, and Napa. No Heat Risk advisory has been implemented at this time due to less area coverage and temperatures at marginal threshold. However, ground observations at Daly Place, Middletown, and Hidden Valley Lake have reached or exceeded 100. Tomorrow`s forecast will lower the probability of heat risk as cooler trends prevail. NBM remains consistent with temperatures diminishing on Friday as upper level ridging shifts south and a trough develops over the Pacific NW. Stronger westerly to northwesterly winds are expected to develop on Friday across the interior especially interior Mendocino and Lake counties. More substantial cooling along with stronger west to northwest winds are expected in the interior this weekend as another 500mb trough dips down from the NW. Strongest winds will most likely occur on Sunday with the passage of a shortwave trough. With fine grassy fuels cured, the strong westerly to northwesterly winds may pose a slight risk for rapid spreading grass fires. The highest risk appears to be in Lake and perhaps eastern Trinity and southern Mendocino. This trough is forecast to be relatively dry and right now the potential for any precipitation is quite meager, 5-10% chance for mostly Del Norte late in the weekend. The cooler/drier air will also result in chilly overnight temperatures once winds decouple. There is a chance (20-40%) for brief morning frost in the colder valleys of Trinity and eastern Humboldt counties on Sunday. The frost threat will persist into Monday morning with about the same probability of occurrence. Also, rain possibilities increase early to mid next week (June 17- 19), though still quite meager with NBM probabilities for 0.10in or more in 24 hours no more than 22% for mostly Del Norte and northern Humboldt counties. NBM has temperatures trending upward by mid week, however the trough may linger into mid next week and strong warming appears unlikely at this point. /DB /EYS && .AVIATION...Marine stratus redeveloped along the coast from Cape Mendocino to Del Norte. A couple of pireps reported bases around 600 feet average and tops around 2,000 feet at ACV, but halve that height at CEC. Stratus was slightly more extensive today and more stubborn to mix out. Winds were "unhurried" to ramp up today, but finally started to increase by mid-afternoon (at least at CEC). Winds should stick around up to a couple of hours after sunset. Low clouds will return to the coast overnight...starting first around Humboldt Bay, then advecting toward CEC. UKI will continue to stay VFR with typical afternoon breezes. /TA && .MARINE...Gale conditions are in full swing across the outer waters this afternoon with nearshore wave heights reaching 10-12 feet. Wave periods building to 10-11 seconds as a SW long period swell fills into the waters. Peak seas and winds expected to develop late this evening and overnight, with significant wave heights approaching 15 feet alongside gusts up to 45 knots. Hi-res models are highlighting potential for an area of localized gusts reaching 50 knots in the corridor of an expansion fan downwind of southern Oregon. Steep and hazardous seas expected to continue through late Thursday - gusty winds will slowly diminish and decrease in zone coverage as the thermal trough and associated pressure gradient slackens. Fairly marginal gales expected to persist through Friday in the southern waters within an expansion fan downwind of Cape Mendocino. Otherwise, seas will begin to dip below 10 feet for the start to this weekend. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Hazardous Seas Warning until 9 AM PDT Thursday for PZZ450. Gale Warning until 9 PM PDT this evening for PZZ455. Gale Warning until 9 AM PDT Thursday for PZZ470. Gale Warning until 3 AM PDT Friday for PZZ475. && $$ 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