FXUS66 KEKA 141310 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 510 AM PST Fri Feb 14 2025 .SYNOPSIS...Shower activity is expected to dissipate this afternoon. Lingering cold air will promote colder temperature tonight, with freezing temperatures across the interior valleys. Dry and calm weather is forecast for Saturday, followed by more rain and mountain Sunday through early next week. && .DISCUSSION...Satellite imagery shows the Thursday's storm system continuing to eject eastward away of Northwest California. Doppler radar depicts isolated to scattered showers across the area early this morning. Rain amounts over the last 24 hours (3AM Thursday to 3AM Friday) ranged from 1.5 to 3 inches, with localized higher amounts up to 5 inch over the west-southwest facing windward terrain in Southwest Humboldt and Mendocino County. The Russian River at Hopland remain exceeding flood stage (15 feet) early this morning. This main stem river will continue to receding and fall below stage this morning. Shower activity is expected to gradually taper off late this morning as a shortwave ridge will builds in quickly downstream of the departing trough Friday afternoon. Dry airmass will begin to filter across the area this afternoon through late tonight. Lingering cold airmass, clear skies and strong radiational cooling will promote colder temperatures tonight, with freezing temperatures across the interior valleys. For areas where skies clear out quickly, areas of valley fog are expected to develop tonight into Saturday. Pretty quiet weather conditions is expected for much of Saturday, before another system approaches the area Saturday evening. A broad upper level trough will move across the NEPAC on Saturday. This feature will gradually weaken as it approaches the Pacific Northwest, while a decay frontal system approaches Northwest California. A low-level jet in advance will bring WAA in from the west and aiding in snow levels rise about 4500 feet Saturday evening and night. Modest pressure gradient tighten late Saturday along the North Coast. Gusts from 25 to 35 mph will be likely over the coastal headlands and exposed ridges. Light to locally moderate rainfall rates is forecast to arrives Saturday night for the northern portion of the forecast area, then continuing into Sunday with rain chance increasing for areas east and south. These front will be progressive and have less moisture flux compared to Thursday storm. Total rainfall amounts from this system is forecast to range from 0.5 to 1.5 inches along the North Coast from Saturday evening through Monday afternoon. The highest amounts are forecast to the farther northern portion of Humboldt and Del Norte counties. Less amounts are forecast for Mendocino and Lake counties with total rainfall from few hundredths to 0.30 inches. Ensemble and deterministic models continue to suggest another system approaching the area by mid next week, with little potential (20% chance) of even moderate rainfall. Light rain is most likely, again focused on the North Coast. /ZVS && .AVIATION...Winds have turned northwesterly overnight as the low center moves onshore into southern OR and weakens. Gusts 20 to 30 knots expected to continue at all terminals through early this afternoon. Wind shear is likely in UKI until around sunrise before winds diminish aloft. MFVR ceilings and reduced visibility's with scattered rain showers will gradually diminish through this evening. Light offshore winds will develop overnight in anticipation of another frontal boundary approaching the area Saturday. && .MARINE...NW winds are still gusting 20 to 30 knots this morning as a large nearshore westerly swell fills into the waters. This swell is still on track to peak at 15 to 16 feet at 15 seconds, enhancing already elevated wave heights and generating high surf conditions. Significant wave heights approaching 18 to 20 feet are possible this morning before quickly diminishing along with winds by late this evening. A brief period of sub-advisory conditions will be short lived before another fast moving system brings another round of gusty southerly winds Saturday into Sunday. && .BEACH HAZARDS...A large westerly swell will peak this morning at 15 to 16 feet at 15 seconds, producing significant wave heights 18 to 20 feet. This swell will be enhanced by elevated NW winds developing on the backside of a strong low pressure system. Max surf heights 20 to 22 feet are possible during through early afternoon, especially on NW oriented beaches. Large breaking waves along the coast will lead to increased wave run-up on beaches. Avoid large rocks, jetties, steep beaches, and never turn your back on the ocean. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... High Surf Advisory until 2 PM PST this afternoon for CAZ101- 103-104-109. Wind Advisory until 6 AM PST early this morning for CAZ115. NORTHWEST CALIFORNIA COASTAL WATERS... High Surf Advisory until 2 PM PST this afternoon for PZZ415- 450. Hazardous Seas Warning until noon PST today for PZZ450-455- 470. Hazardous Seas Warning until 9 AM PST this morning 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