textproduct: Eureka

SYNOPSIS

Isolated showers and thunderstorms are likely in the interior this afternoon/evening with less of a chance Monday afternoon. Chilly morning temperatures are expected Monday morning for the coldest interior valleys. Drier weather returns mid next week.

DISCUSSION

The deep marine layer from this morning continues to burn off this afternoon. A low moving through California south of the region will continue to push moisture up the Central Valley and onto the eastern slopes of the Coastal Range. As a result, showers and isolated thunderstorms are possible again this afternoon and evening over Trinity, eastern Mendocino, and northern Lake. There is about a 15 to 20 percent chance of thunderstorms over this area this afternoon, with chances dropping significantly for Monday afternoon as the low continues away from the area. High-res models show areas of moderate to locally heavy rain rates over the higher terrain in eastern Trinity, eastern Mendocino, and far northern Lake Counties. HREF is showing around 50% chance for over 0.25 inches of rain in these areas. Instability currently looks meager, meaning isolated showers are more likely, but isolated thunderstorms could still be a possibility this afternoon/evening. Showers will taper off again overnight.

A Frost Advisory has been issued for the coldest valleys of southern Trinity and southeastern Humboldt counties with lows below 36 likely. Cloud cover may hinder widespread lower temperatures, however. Drier and warmer weather is likely to return by mid next week as ridging redevelops.

AVIATION...18Z TAFs

VFR conditions developed Sunday with some general scattering of the low clouds. Some terrain enhanced stratus to MVFR levels will be possible throughout the day. A light afternoon westerly seabreeze may present some occasional gusts at the coastal terminals through Sunday afternoon, but winds will be light otherwise. Mostly VFR to MVFR conditions expected through this 18Z period. Some light drizzle will be possible late Sunday through early Monday, which would lower VIS at times.

MARINE

Northerlies have weakened from a passing trough. Seas will range from 5 to 7 feet from a mix of lingering short period seas and a small, mid to long period westerly swell. The trough passes east Monday with high pressure building back in behind it. The northerlies will increase in response, beginning Monday afternoon. Northerlies are forecast to reach 20 to 25 kts by Tuesday afternoon. The northerlies will continue to gradually trend higher through the end of the week. There is a 50 to 60% chance for gale strength gusts over the out waters starting Thursday, with higher chances around and south of Cape Mendocino.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory from 2 AM to 9 AM PDT Monday for CAZ106-108.

NORTHWEST CALIFORNIA COASTAL WATERS... None.