FXUS66 KEKA 270737 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1237 AM PDT Mon Oct 27 2025 .SYNOPSIS...High pressure is building into the area bringing dry weather and this is expected to persist through much of the work week. Chilly nights and generally sunny afternoons are expected each day. A few clouds and showers are possible in Del Norte county Wednesday morning. The next chance for possible widespread rain is next weekend. && .DISCUSSION...High pressure is building into the area this morning. The rain has moved out of the area, but left widespread cloud cover over the interior. The winds at the coast have turned north to northeast and this is keeping the coast clear at this point. Temperatures have been dropping quickly so have issued a frost advisory for the Humboldt and Del Norte coast. There may be some areas that get fog and stay warmer, so confidence is low on the frost coverage. This morning the inland valley clouds will likely be slow to clear and this may hold temperatures down a bit. Tonight clear skies are expected to allow temperatures to drop quickly. Temperatures aloft warm quite a bit so this is expected to make frost less widespread. Still temperatures are expected to drop into the mid 30s in northeastern Mendocino and Trinity counties. So have issued a frost advisory to highlight this. This may need to be expanded or upgraded to a freeze warning if it is drier than expected. Tuesday afternoon temperatures are expected to be notably warmer across the inland areas with highs in the upper 60s and 70s. Tuesday night into Wednesday morning a frontal boundary is expected to move by to the north of area. Currently this is only expected to bring a few light rain showers to Del Norte county and just some clouds elsewhere. Still it will likely be enough cloud cover and moisture to keep frost out of most areas. Thursday clear skies and dry conditions are expected to return with frost possible overnight in the colder valleys. Friday and into the weekend there is the potential for more widespread rain to return to the area. The ensemble clusters show a weather system moving into the Pacific Northwest and are fairly confident on this. The big question is how far south the precip will make it. All the clusters have rain in Del Norte county and some of them bring it as far south as Lake county. The IVT plumes for Humboldt county show a few members reaching up to 750 kg/m/s, a fairly strong AR. However the majority of them are less than 500 j/kg/s. MKK. && .AVIATION...(06Z TAFs)...An extended period of sourced moisture funneled into the area terminals, bringing precipitation and gusty winds. The passing low has switched wind bearing back to northerly, also improving flight categories the evening sets in. HREF has most of the coastal clouds clearing out and with an offshore easterly wind component overnight, this could further support VFR/MVFR through the TAF period and well into Monday morning. Interior valleys will likely retain cloud cover as winds decouple with a slight inversion as shown by model soundings. Radiational cooling and drainage breeze from cool, dense air will likely fill the valleys overnight. Northerlies will return by the afternoon, Monday. /EYS && .MARINE...After the passage of a low pressure system, winds remain elevated in the southern outer waters but are easing after Gale force gusts. The sea state remains hazardous with 10-13 foot seas at 12-14 seconds as a northwest swell continues in all area waters. The swell is projected to ease over the next few days, yet conditions are expected to remain hazardous for small crafts in the southern waters into Tuesday at least and so an SC.Y has been hoisted for zones PZZ455 and PZZ475 as high pressure fills in. Winds will build with the diurnal swing during the daytime as northerlies usually do leading to acceleration around Cape Mendocino, into the leeward. /EYS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Frost Advisory from 2 AM to 9 AM PDT Monday for CAZ101-103. Frost Advisory from 2 AM to 9 AM PDT Tuesday for CAZ107-108- 111. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT Monday for PZZ450-470. Small Craft Advisory until noon PDT Tuesday for PZZ455-475. && $$ 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