textproduct: Eureka

SYNOPSIS

A front will bring a quick passing period of rain to primarily Humboldt, Del Norte, and western Trinity counties Wednesday morning. Showers will linger into Wednesday night. Elsewhere very little or no rain is expected as this front moves through the region. Dry conditions will return by Thursday into this weekend.

DISCUSSION

A band of rain is expected to move through primarily Humboldt, Del Norte, and western Trinity counties beginning early Wednesday morning with accumulation of a tenth of an inch in the south to over a half inch in some of the favored terrain in northern Humboldt and Del Norte counties. Farther south and east less rain is expected where only several hundredths are forecast to as little as no rain in southern Mendocino and Lake counties. Behind the quick passing morning front, northwesterly winds will increase and gusty conditions are likely for coastal areas and ridgetops Wednesday and Wednesday evening. Wind gusts over 30 mph will be possible in typically windy locations, but winds to advisory levels are not expected (except maybe at Cape Mendocino). Scattered showers will persist in Del Norte and Humboldt counties into the evening hours.

Gradually drying northerly flow will bring in cold air and the potential for overnight lows into the 30s in many interior valley locations. The growing season has resumed in Mendocino County and coastal areas of Humboldt and Del Norte, so it is likely that some locations may need frost or freeze warnings Thursday morning and again Friday morning. The most likely location will be in interior, northern Mendocino County.

Dry conditions are expected for much of the next week as high pressure builds over the eastern Pacific and storm systems are pushed toward the north into Oregon and Washington. Slight chances for rain remain in the forecast for Del Norte County much of the week with any individual front possible of bringing a shower or two to the extreme northern portions of the area, but overall conditions are expected to be dry with ridging dominating over Northwest California. /RPA

AVIATION

A frontal boundary is approaching the area and is expected to bring some rain showers. The CIGS along the coast area already IFR to MVFR but may lift slightly ahead of the front. The heavier showers in the front may bring some more MVFR to IFR conditions early in the morning around sunrise. Behind the front there may be a few lingering showers, but generally VFR conditions are expected. Northerly winds are expected to increase in the afternoon, especially in KUKI. MKK

MARINE

The southerly winds have expanded this morning ahead of the front approaching the area, but areas south of Cape Mendocino remain more west to northwest. Early Wednesday when the front moves through there is expected to be a fairly abrupt shift to northwest. The winds are also expected to increase to around 15 to 20 kt by daylight on Wednesday or possibly earlier. These winds are expected to gradually increase through Thursday night. Gale force gusts are expected to start Thursday morning in the southern waters and expand north into the northern waters Thursday afternoon. Confidence is high that there will be gale force winds, although some questions remain how far north they will make it and exactly when they will start. These may continue into the weekend at least in the southern waters. It looks like at some point around Saturday a shortwave is expected to move by to the north area and briefly weaken the pressure gradient briefly. Timing is still fairly uncertain on this.

The seas are currently low, only around 2 to 3 feet at around 10 seconds. These are expected to generally persist until the wind driven waves start to pick up on Wednesday. These winds driven waves are expected to quickly build to around 8 to 14 feet by Thursday night and remain elevated and the dominant wave into the weekend. In addition to the wind driven waves, the models are now showing a swell in addition to the wind driven waves. It looks like it will build to around 8 to 10 feet at 10 to 12 seconds. In the southern waters this will be fairly close to the wind driven waves expected to be around 7 to 10 feet at 7 to 9 seconds. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 2 AM to 1 PM PST Thursday for PZZ450.

Small Craft Advisory from 10 AM this morning to 1 PM PST Thursday for PZZ455-475.

Gale Watch from Thursday afternoon through Friday morning for PZZ455.

Small Craft Advisory from 2 PM this afternoon to 1 PM PST Thursday for PZZ470.

Gale Watch from Thursday afternoon through late Friday night for PZZ475.