


Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
594 FXUS66 KEKA 160701 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1201 AM PDT Wed Jul 16 2025 .SYNOPSIS...Inland temperatures continue trending down this week while still remaining warm. The coastal stratus will become more persistent over the coastal regions, lowering the daytime highs for some areas. && .DISCUSSION...A series of shortwaves moving through the Pacific Northwest has weakened the ridge and brought slightly cooler (but still hot) temperatures in the interior. High 80`s to 90`s are forecast for much of the interior, with the highest temperatures found in Trinity County and northeastern Humboldt County. Along the coast, the marine layer is limited to the lowest 1000 ft, and rising, early this morning. The marine layer is expected to deepen over the coming days as the ridge continues to weaken. Some areas along the coast may see drizzle overnight and in the mornings. Offshore eddies with relatively light winds are likely to reinforce stratus, including during the day, for the immediate coastal areas. Partial clearing is still possible in the afternoon, but likely temporary. The shortwave does introduce some elevated instability this afternoon, mostly in Trinity County. Moisture remains limited and there is still a good amount of CIN, so thunderstorms are unlikely (5-10% chances), but some cumulus is possible. There is a similar setup Thursday afternoon. Instability will improve air quality in the afternoon, except immediately downwind from the fire. A similar pattern remains in place for much of the week with a series of shortwaves moving into the Pacific Northeast. This will keep temperatures moderated in the 90`s. By Thursday, NBM probabilities of triple digits in Trinity and northeast Humboldt fall off to less than 30% into the weekend. JB && .AVIATION...(06Z TAFs) Coastal stratus has returned to coastal terminals bringing a return to IFR/LIFR conditions as a strong surface inversion traps moisture close to the terminals. Coastal stratus is expected to erode to the coast by Wednesday afternoon and then fill back in by Wednesday evening. Inland, VFR conditions are expected with potential for smokey visibilities as well as light surface (<10kt) and elevated winds (<15kt) in Trinity, interior Humboldt and NE Mendocino counties. && .MARINE...Small craft conditions continue to ease into early Wednesday morning. As these winds diminish, the steep wind driven seas are forecast to weaken, as well, leading to calm conditions Wednesday. Stronger southerly winds are expected directly offshore and north of Cape Mendocino Wednesday. Overall, however, moderate breezes are expected from Wednesday through Friday. Fog and stratus is to be expected as well with potential degraded visibilities through the next 24hrs, especially at nighttime and in the early mornings. && .FIRE WEATHER...Some moisture and instability aloft will bring a 5-10% chance for dry thunderstorms in northern Trinity County this afternoon and evening and again Thursday. Min RHs remain low, in the teens and 20s, while overnight recoveries remain good. A weak shortwave trough will increase southerly to southwesterly winds locally this afternoon in Lake and Mendocino counties. Inland temperatures will inch slighlty higher late this week and through the weekend. RHs are likely drop to drop slightly with increasing westerly winds through that period. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT early this morning for PZZ470-475. && $$ 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