textproduct: Eureka

AVIATION

A compressed marine layer will maintain IFR and LIFR ceilings across coastal terminals through the morning hours. Dense fog will reduce visibilities below 1 mile at KACV and KCEC before slow lifting occurs after 18Z. High pressure will keep ceilings hovering around 300 to 700 feet through the afternoon before lowering back to the surface after sunset. In contrast, inland terminals including KUKI will remain VFR with clear skies and typical diurnal wind patterns.

MARINE

North winds will steadily increase today across the outer waters, generating near-gale force gusts up to 30 knots south of Cape Mendocino. A Small Craft Advisory is in effect for the outer waters through late Thursday night, and will expand to the inner waters south of Cape Mendocino this afternoon as steep waves of 5 to 8 feet propagate nearshore. Winds will briefly ease on Friday morning as a cold front approaches. However, a steep northwest swell of 6 to 8 feet at 9 seconds will arrive Friday night, keeping seas elevated through Saturday. Strong northerly winds between 20 to 25 knots are forecast to return across all waters late Saturday into Sunday.

FIRE WEATHER

An upper-level ridge remains firmly established over northwest California, keeping hot and dry conditions intact across interior valleys through Thursday. Daytime highs on interior valley floors will reach the 90s both today and Thursday. High-resolution guidance continues to indicate a 10% probability of localized triple-digit heat up to 105 degrees, strictly confined to the lowest elevations of the Klamath and Trinity river corridors. Minimum relative humidities will drop into the teens across these interior zones during the afternoon hours. Along the coast, a compressed marine layer will keep low clouds, cool temperatures, and patchy dense fog entrenched.

A significant pattern change occurs Friday into Saturday as a deeper upper-level trough and cold front move into SOC 6. This front will bring a high probability of wetting rain to coastal areas, with a 50% to 60% chance of exceeding 0.10 inches in coastal Del Norte County and a 30% to 40% chance in northern Humboldt County. Interior areas will remain dry outside of isolated sprinkles, but will experience a temperature drop of 15 to 20 degrees, dropping Saturday highs into the 70s. As the core of the cold trough moves overhead on Saturday afternoon, localized destabilization will support around a 10% chance of thunderstorms across the higher terrain of northeastern Trinity County.

Winds will remain light with standard diurnal afternoon breezes inland today and Thursday. Behind the front on Friday afternoon, strong westerly winds will develop across Lake and southern Mendocino counties. There is a 70% chance that wind gusts will exceed 30 mph in low elevations, with a high probability of gusts over 40 mph across exposed ridges. Breezy conditions continue Saturday afternoon, with a 50% chance for lower elevations to see gusts over 30 mph. Winds are forecast to shift to the northeast at least briefly across Lake County by Sunday afternoon.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Friday for PZZ455.

Small Craft Advisory until 9 AM PDT Thursday for PZZ470.

Small Craft Advisory until 3 AM PDT Friday for PZZ475.