FXUS66 KEKA 210812 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 112 AM PDT Mon Sep 21 2026 .KEY MESSAGES... * Warm and dry conditions for interior areas through Wednesday. * A shallow but strong marine layer along shore will weaken over the next couple of days with some clearing possible by Tuesday. * Cold front Thursday into Friday with a 20% chance of light wetting rain along the North Coast. && .SYNOPSIS...Warm and dry conditions will persist across the interior through Wednesday. The coastal marine layer will begin to weaken today with better clearing expected by Tuesday. A cold front may bring some light rain to Humboldt and Del Norte counties on Thursday or Friday. && .DISCUSSION...Low pressure moving into the Central California Coast will help to ease high pressure over the next couple of days. Dry and warm conditions will persist through Wednesday across the interior with varying levels of high level cloudiness across the region. Ensemble models have started to show better clarity for the forecast by late weak. Most show a quickly passing area of high pressure on Thursday to be followed by a cold front Thursday night into Friday, helping to drop interior highs into the low and mid 70s for next weekend. The front will also disrupt and lift any marine layer that manages to reform on Thursday. Most models still show the front mostly dry, but now about 20% show very light wetting rain focused along the North Coast. Weak high pressure is most likely to quickly rebuild behind the front. Despite the cooler air, there is little potential (20% or less even for the coldest valleys) for frost behind the front. && .AVIATION...A strong marine inversion continues to hold coastal clouds along the coast with IFR to LIFR conditions expected overnight into Monday morning. Patchy areas of drizzle are possible in the morning hours. As an area of low pressure spins over California, light offshore flow on the north side of this low will likely start to weaken the inversion and bring increasing clearing, but this may not occur until Tuesday in northern areas at CEC and ACV. IFR to low end MVFR is likely to persist Monday the two primary coastal terminals. Farther inland any morning near coast valley clouds will dissipate in the monring hours leaving VFR through the day. && .MARINE...Moderate to isolated strong north winds have now built throughout the outer waters, though condition remain calmer closer to shore, especially north of Cape Mendocino. Short period seas have built in response to the winds with waves over 8 feet in the outer waters and some steep seas up to 6 feet migrating into the inner waters. Similar winds will persist for the next several days and even strengthen in the southern outer waters with some near gale conditions by Tuesday morning. Winds will gradually weaken form north to south mid to late week as a cold front approaches. Short period wind waves will continue to dominate the environment alongside a very minor southwest swell. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 PM PDT Wednesday for PZZ455. Small Craft Advisory until 9 AM PDT Wednesday for PZZ470. Small Craft Advisory until 9 AM PDT Thursday for PZZ475. && $$ 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