Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
065 FXUS66 KEKA 062112 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 212 PM PDT Mon Oct 6 2025 .SYNOPSIS...Above normal temperatures continue through Tuesday. The pattern begins to change Wednesday with cooling temperatures from an approaching trough. Rain chances increase late week and particularly Friday. Overnight lows will also trend cooler. && .DISCUSSION...Offshore flow has contributed to much above normal temperatures Monday, with 70s to low 80s along the coast. Lighter offshore will develop tonight with weakening of the thermal trough, but some of the interior ridges will be breezy. Another mostly cloudless, full sunshine day forecast Tuesday. Daytime highs will tick up slightly higher for the interior on Tuesday, while the coast looks to be slighlty less warm than today with the weaker thermal trough. A weak shortwave will push into into Central California, with no impacts other than perhaps some increased cloudcover over Lake County late Wednesday. A stronger NE Pacific trough will take shape late wednesday, with evolution into a closed low Thursday as it drifts south toward N CA. Cold 500 mb temperatures of -25C and modest surface CAPE upwards of 250 J/kg with the low will bring the chances for thunderstorms and higher rainfall rates. With the convective nature of this low, exact rainfall over the entire forecast area. The highest chances are over the King Range, the ridges of Humboldt and most of Del Norte County. NBM is showing moderate confidence for general rainfall totals over 1 inch in 24 hours (40-60%). Chances for 72 hour rainfall over 2 inches is strong, around 70%. Where these higher amounts are concentrated is still uncertain given the setup. What is also looking interesting is the modest surface cape and shear profiles the sounding are revealing, and with a strengthened 250 and 500 mb jet. There are hints of a veering wind profile over the ocean Friday, and this would point to a waterspout threat. There may be convective activity that pushes somewhat inland, and soundings currently support this scenario. A slight jog north or south of the low would change this forecast, so higher confidence in details will come into focus in the coming days. JJW && .AVIATION...(18Z TAFS)...Clear skies with light and variable winds below 10kt is expected through the forecast period at all forecast aerodromes. Low possibility (20% chance) for shallow mist and haze at coastal terminals this evening nearby the ocean. Light easterly breezes by late evening will significantly reduce that potential through the night. Visible satellite imagery this morning showed areas of fog and low clouds in the interior valleys, specifically in southern Humboldt and northern Mendocino Counties. These pockets of LIFR burned off quickly. The gradual drying over the last 3 days will most likely not yield more fog and low clouds in these valleys. && .MARINE...Steep wind waves have eased below criteria this afternoon. Light and variable winds to 10 kt or less are forecast to continue this afternoon through tonight. Northerly winds will begin to trend stronger Tuesday night through Wednesday. NBM probability for gusts over 30kt increases to 40-50% initially over the outer waters Tuesday night. These 30 kt gusts will likely (80% chance) expand into portions of the inner waters on Wed. Primary area for these stronger corridors of winds inside 10NM will most likely be in the lee of Cape Mendocino (40-60% chance) and perhaps around Pt St George (20% chance) during the afternoon and evening. High resolution models may end up coming in hotter and heavier with northerly winds and a few localized gale gusts to 35 kt are possible. Steep northerly wind waves will also rebuild to 6 to 8 ft (significant wave heights) by Wed and seas will once again become hazardous to small craft. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ 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