289 FXUS66 KEKA 182300 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 300 PM PST Wed Jan 18 2023 .SYNOPSIS...Beneficial rain and high elevation snow will come to an end tonight. Cold temperatures with valley frost and fog development will then be probable during most mornings Thursday into the weekend. In addition, dry weather is anticipated during the second half of this week. && .DISCUSSION...A cold front was moving onshore across Humboldt County this afternoon. The front will continue sliding south across Mendocino County, while dissipating inland. Before the front exits NWRN CA, quarter to one half inch per hour rainfall rates will occur along the front...and an isolated thunderstorm can't be ruled out over the coastal ridges of SWRN Humboldt and Mendocino Counties. In addition, several additional inches of snow will occur for elevations at or above 3000 feet across portions of the interior highlands this evening. Otherwise, visible satellite imagery shows rapid clearing taking place shortly after frontal passage. That trend will favor strong radiational cooling tonight, particularly across interior valleys, with most lows falling into the 20s. Areas of frost will occur as a result, and patchy fog will be possible as well. Similar morning conditions are forecast to occur through at least Saturday. After this evening, ensemble based forecast guidance shows an upper-level ridge becoming established over the NERN PAC. That feature will favor dry weather Thursday through the middle of next week. && .AVIATION...Rain and post frontal showers will continue through the TAF period as the short wave moves to the southeast. Subsidence fills in after the boundary passage and should clear skies a bit. Flight categories at KCEC and KACV have improved to MVFR/VFR after the frontal passage and will prevail with variable winds. Ceilings will linger around 4000 to 5000 feet through the TAF period at the coastal terminals. Low Level wind sheer remains a hazard at KUKI as it is the last terminal to face the frontal boundary. Light northerlies and overcast ceilings around 2000 to 3000 feet at KUKI and potentially some fog development overnight as winds calm and skies clear. /EYS && .MARINE...Seas will remain elevated through the week due to a combination of westerly swells and steeper short-period waves. Southerly gusts have veered to a northerly bearing after the passage of a frontal boundary. Northerly winds strengthen on Thursday by the late afternoon. Saturday evening welcomes another round of stout northerlies which will elevate to gale force in the southern outer waters by Sunday morning. Longer period northwesterly swell will fill in by Saturday. /EYS && .BEACH HAZARDS...A long period west-northwest swell will build Friday night into Saturday and will pose a moderate risk for sneaker waves or set behavior. If shorter period waves do not occur, the risk will be higher on Saturday. Another long period swell may bring another risk for sneaker waves early next week (Mon/Tue). && .COASTAL FLOODING...High astronomical tides will likely yield coastal flooding around Humboldt Bay, particularly King Salmon and the Arcata Bottoms during the next 5 days. High tides are forecast to peak near 8.71 feet on Saturday. If the current half foot anomaly persists, water levels will reach or exceed 8.8 feet and flooding will occur in the above mentioned areas. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Winter Weather Advisory until 7 PM PST this evening for CAZ107-108. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PST Friday for PZZ450-455- 470-475. && $$ 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