textproduct: Eureka

SYNOPSIS

Dry conditions will persist through the weekend. A slight chance of rain will return Monday and Tuesday with better chances for widespread rain over the region Tuesday night into Wednesday.

DISCUSSION

Northwest California will remain wedged between a building ridge over the southwestern US and a developing trough off the west coast today through this weekend. Gradually the trough will begin to win out resulting in the warmest high temperatures today and a cooling of temperatures through the weekend. However, with gradually increasing moisture across the region, overnight lows will also warm and tonight should be the last night of frost formation in areas where the growing season has already begun. Thus, one last frost advisory has been issued for northern interior Mendocino County Saturday morning.

Dry conditions will persist through Sunday. Sunday night a trough will approach the region bringing a 20-40% chance of showers Monday and Tuesday , with the highest chances over the interior during afternoon heating. A more potent front is likely to approach the area Tuesday night into Wednesday with the potential for gusty ridge line winds and a quick burst of moderate to heavy precipitation. Overall, rainfall this rain is expected to be generally beneficial to the region and impacts should be minimal. However, depending on the rain rates, isolated flooding of poor drainage areas could occur. Additionally, snow levels will fall with and behind the front to below 5000 feet on Wednesday and down to 3500 feet for northern areas by Thursday morning. Light accumulating snow is possible as showers linger into Thursday and enough snow over 5000 feet in northern Trinity County could necessitate a winter weather advisory for Scott Mountain Pass.

AVIATION

Aside from very localized marine stratus around Humboldt Bay, VFR conditions have quickly built all across the area today under sunny skies and gentle to moderate north wind. VFR conditions will continue into the evening, though weaker winds and increased moisture may help for a shallow and weak marine layer on the coast. All told, there is a roughly 20% chance of IFR conditions at CEC late overnight and a 40% chance of IFR conditions at ACV. Regardless of overnight conditions, VFR conditions will quickly return Saturday. /JHW

MARINE

Northerly winds will decrease through the weekend as an area of low pressure off the coast weakens surface high pressure over the eastern Pacific. This will allow the steep, short-period seas to subside and eventually for all headlines to expire for a brief period Sunday. Northerlies will increase again behind a weak front that moves through the waters Sunday night with more small craft advisories likely needed, especially in the outer water zones. Confidence is increasing in the potential for strong southerlies ahead of another front sometime Tuesday night into Wednesday.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory from 4 AM to 9 AM PDT Saturday for CAZ110- 111.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 6 AM PDT Saturday for PZZ450-455.

Small Craft Advisory until 6 AM PDT Sunday for PZZ470-475.