textproduct: Eureka

AVIATION...18Z UPDATE

Marine stratus continues to force LIFR conditions for the North Coast. Satellite imagery shows an eroding marine layer from the mountains toward the coast with possible VFR between 18-19Z. North winds will continue for ACV while southerly light winds remain along CEC through the next hour or so before switching to northerlies through the afternoon. Inland terminals will see afternoon gusts up to 15-20mph and VFR conditions. Winds aloft near the coast around 2500 ft AGL will remain strong with possible mountain waves near the King Range and other terrain close to the coast.

PREV DISCUSSION

/issued 1256 AM PDT Wed Sep 30 2026/

KEY MESSAGES...

* High pressure builds through the rest of the week, bringing an extended dry period with interior valley high temperatures warming into the 80s and 90s.

* Northwest gusts are expected again Wednesday with gusts up to +30mph for the King Range and other exposed terrain and gusts up to 20-25mph for North Coast headlands.

SYNOPSIS...Upper-level ridging builds over the West Coast this week. A warming trend is expected for inland areas with coastal areas being more likely to have morning overcast or foggy conditions.

DISCUSSION...The forecast are is being dominated by a Pacific high pressure center off the coastline by the 140W longitude and a developing thermal trough developing in the wake of Hurricane Polo. This will lead to a more summer-like pattern as the week goes on. Inland areas can expect warming through the end of the week with inland valleys reaching the high 80s to low 90s. The Russian River Valley even has around a 50% chance to reach >95F Thursday. North Coast areas can expect overcast skies developing each evening with areas of localized fog and drizzle. These are likely to scatter out in the afternoons.

Another expected result of this summer-like pattern is gusty north winds along the coast. Marine waters will remain hazardous due to short-period waves caused by winds up to 35-40kts in the windiest spots. Directly along the coastline and in river valleys close to river mouths for Humboldt and Del Norte Co., expect breezy afternoons. The King Range will receive the bulk of the winds with gusts reaching up to 50kts on the exposed ridgetops as northerlies flow over the E-W orientated topography. Inland areas are likely to see gusts up to 15-20mph in the afternoons.

This weather pattern is expected to continue through the weekend into next week as an dip in the jet stream remains far away from the eastern Pacific Ocean. The GEFS and EPS ensemble models show high pressure continue through the middle of next week. So expect these warm and dry conditions to continue.

MARINE...Fresh northerlies continue due to the pressure gradient between offshore high pressure and the interior thermal trough.

* Northern Inner Waters: Northerlies of 10 to 20 kt will generate steep short-period seas. A west-northwest swell at 12 to 14 seconds continues today. A Small Craft Advisory remains in effect through Thursday morning.

* Northern Outer Waters: Northerlies of 20 to 25 kt with gusts to 35 kt (mainly in the lee of Cape Blanco) will build combined seas to 10 to 11 ft. A Small Craft Advisory remains active through early Wednesday morning with a Gale Warning taking over until Thursday morning.

* Southern Inner Waters: Fresh to strong northwest winds of 20 to 25 kt with gusts of +35kt (mainly in the lee of Cape Mendocino) will maintain steep seas. A Gale Warning has taken effect and will remain in effect through late this evening.

* Southern Outer Waters: Gale force conditions develop in the lee of Cape Mendocino, where northerly winds of 25 to 30 kt with gusts up to 40 kt will yield steep, hazardous combined seas of 11 to 12 ft. A Gale Warning remains in effect through Thursday morning.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Thursday for PZZ450-455.

Gale Warning until 9 AM PDT Thursday for PZZ470-475.