textproduct: Eureka

KEY MESSAGES

* Above normal interior temperatures likely through Thursday.

* Chances for light rainfall for Del Norte and northern Humboldt Saturday.

* Locally elevated fire danger Thursday, Friday, & Saturday afternoons for the interior.

SYNOPSIS

Cooler temperatures return to the coast Thursday and across the area Friday into the weekend. Light rain is possible for the northern half of the area Saturday. Westerly to northwesterly winds will increase the fire risk for the interior through Saturday.

DISCUSSION

The once strong ridge of high pressure is weakening as troughing begins to ascend in from the north. Temperatures will begin to lower as quickly as they increased, with high temperatures over 10 degrees cooler by Friday. The return of surface moisture and weakened offshore flow has allowed for coastal stratus to reform. Levels are shallow, and some areas of fog are likely. The stratus may be somewhat persistent around portions of the coast today. The addition of cloudcover may further cool the daytime highs at the coast today.

Subtropical moisture from the remnants of Hurricane Marie arrived Wednesday, bringing some high clouds and virga showers. The moisture and weak perturbation will pull eastward today, perhaps allowing for a couple isolated virga showers on the way out.

Troughing rebuilds Friday into the weekend, returning near normal temperatures and coastal stratus by Friday. By this weekend, much of the interior is forecast to be in the 70s and 80s with the coast in the low 60s. Light rain is becoming likelier for the northern portions of the area, with Del Norte having an 80% chance of any measurable rain, and northern Humboldt up to a 40% chance. Wetting rain (over 0.1") chances remain low at around 40% in Del Norte and 20 to 30% chances in northern Humboldt. /JB

AVIATION

Offshore flow weakened which allowed for stratus to form along the coastal areas. Chances for the stratus starts north along the Del Norte Coast after 11Z, followed by progression southward into Sunrise Thursday. LIFR conditions are likely with the shallow marine layer, along with fog. The fog and coastal stratus may prove to be persistent Thursday with a weak coastal eddy modeled to form. The stratus will fill back in with full force late Thursday. The interior will remain VFR other than some areas of patch ground fog through the early morning hours. Winds will stay light closer to the coast, but afternoon northwest winds will turn breezier over UKI and south through Lake County.

MARINE

Breezy northerly winds return Thursday, particularly in the lee of Cape Mendocino. Near gale force gusts are possible by Thursday evening in the lee of Cape Mendocino and Cape Blanco. Winds ease Friday and Saturday as a weak front moves through the area. Strong northerlies return Sunday. Along with wind driven seas, a long period south swell from Hurricane Marie at around 2 to 3 ft continues through the waters. /JB

FIRE WEATHER

Much warmer and drier conditions continue through Thursday. Afternoon relative humidity will be very low in the interior with most areas seeing single digits and teens. Tonight, offshore winds weaken somewhat which will support the redevelopment of a shallow marine layer and slightly improved relative humidity recoveries. Breezy onshore winds return Thursday afternoon and will elevate fire weather concerns as relative humidities remain low. The winds will be strongest, and the fire danger highest in Lake County and eastern Trinity County with these winds mainly in the afternoon and late evening. Locally critical conditions are possible.

Troughing late this week into the weekend will return cooler temperatures and a deeper marine layer. Afternoon westerly to northwesterly winds will increase Friday and Saturday. The largest areas of concern will be the southern portions of the area, such as Lake County, that will remain dry.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from noon Thursday to 3 PM PDT Friday for PZZ470.

Small Craft Advisory from noon Thursday to 3 AM PDT Saturday for PZZ475.