textproduct: Eureka

SYNOPSIS

A warmer trend is expected entering the weekend with broad high pressure influencing higher winds as well as clearing skies. Temperatures reaching near record highs for the interior as well.

DISCUSSION

Drier conditions continue for the next few days with skies clearing and temperature swings likely to produce daytime highs approaching record values. High pressure broadens over the NE Pacific with pressure gradients steepening over the coastal CWA. As a result, northerlies will ramp up through the afternoon and early evening Friday. Winds return Saturday late afternoon at the eastern periphery of Southern Trinity, Mendocino, and Lake counties at higher elevations. Consequently RH values in these areas will range the mid 20% at their lowest. Fuels are obviously not at play as we are still in the wet season technically but definitely something to watch as we enter the warmer, drier season.

Additionally, we can expect clearing due to the effects of high pressure and consequentially subsidence. Clear skies will enhance the likelihood of long wave radiation, cooling temperatures down overnight which will be noticed Friday morning, hence the issuance of the frost advisory for zones 110-111, northern Mendocino interior.

For the coast, conditions will dry through the week. High pressure will encourage a weak marine layer to form each night, but increasingly strong north winds during the day will encourage quick clearing each afternoon. Gusty north winds pushing close to shore will most likely bring gusts from the Gale conditions offshore and locally higher gusts on ridges. There is high confidence that slightly cooler temperatures will return by early next week as high pressure weakens, but there is little chance of wetting rain until late next week at least when about 20% of ensemble models show a weak trough crossing the area. /EYS

AVIATION...(06/06z TAFS)

VFR conditions are expected to prevail through Friday. Brief MVFR ceilings will remain possible (20% chance) around Humboldt Bay and KACV tonight and Friday. Robust N-NW winds 1000-3000 ft AGL will continue to result in low level shallow turbulence over the coastal mountains and vicinity, especially across southern Humboldt through 06/18Z Fri. This will be particularly hazardous for small and light weight aircraft. Boundary layer mixing will transport higher mountain air down to the surface on Friday as daytime heating commences. Gusty northerly winds are expected again for the coastal aerodromes and perhaps at KUKI.

MARINE

Gale force northerly wind gusts are forecast to continue in the waters through Friday. The greatest coverage, longest duration and strongest gusts so far have been observed in the southern waters. Coverage was more scant with limited duration of gale gusts in the northern waters. Steep seas have risen to 9 to 11 feet at 11 seconds in the northern waters and 11 to 13 feet in the southern waters. These steep northerly waves will be hazardous for small craft through tonight. Hazardous seas are forecast to continue through the day on Friday. Gale force northerly wind gusts (35-40kt) will continue through Friday evening for the southern waters. After decreasing later tonight and early Friday, winds will increase to low end gale gusts for northern waters by early afternoon Friday. Hazardous ocean conditions with occasional gale force gusts and large steep waves are forecast to continue into the weekend, especially for the outer waters and around Cape Mendo. Northerlies strengthen Sunday into Monday with near storm force gusts expected for the southern waters by Monday.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory until 9 AM PST this morning for CAZ110-111.

NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 3 AM PST early this morning for PZZ450.

Gale Warning until 10 PM PST this evening for PZZ455.

Gale Warning until 3 AM PST Saturday for PZZ470.

Gale Warning until 11 AM PST Sunday for PZZ475.