textproduct: Eureka

SYNOPSIS

Some weak clipping fronts will bring small chances of very light coastal drizzle or a few showers between periods of rebounding warm temperatures. Northerly winds will remain gusty, particularly through the early work week. Chilly morning conditions are forecast early to mid week.

DISCUSSION

A cold front will continue through Northwest California keeping temperatures cooler and more in line with averages for this time of year. Also, this weak front will bring light to occasional heavy drizzle this morning, resulting in trace amounts of accumulation. The marine layer is also expected to deepen this morning. Afternoon temperatures will continue to be slightly warmer than average for inland locations in eastern Trinity, eastern Mendocino, and Lake counties.

Northerly winds will remain breezy. A cutoff low to the south will further tighten the pressure gradient against the restrengthening ridge Monday and Tuesday. Northerly winds will increase in response and will be quite gusty this afternoon, in particular. Forecast soundings indicate well-mixing through the boundary layer through this period, allowing for efficient downward momentum transfer and gusty surface winds along the coast. NBM holds a high chance (60%- 80%) for maximum wind gust of 30 mph or higher Monday for areas along the coast and higher terrain areas of interior Del Norte and Humboldt counties. There is a moderate to high chance (40%-60%) for gusts to exceed 35 mph over some of the exposed coastal headlands and over coastal Del Norte and around Cape Mendocino. Winds will ease some Tuesday, but will remain breezy through Tuesday afternoon.

Chilly, and potentially frosty, morning conditions could occur in the wake of the passing front Tuesday and Wednesday mornings. However, on Tuesday morning, lingering elevated winds along with generally overcast skies could result in morning temperatures above 36 resulting in no frost development. As of now, Wednesday seems like the best bet for frosty conditions. For both mornings, NBM indicates that coastal locations from about Albion in Mendocino County to the Oregon border have about a 60 to 80 percent chance of lows below 40 degrees (this includes areas around Humboldt Bay and Crescent City). There is also about a 50 to 70 percent chance for morning low temperatures 36 degrees or less for some regions of interior Del Norte, interior Humboldt, Trinity, and NE Mendocino counties. The growing season has begun for Mendocino, Lake, coastal Del Norte, and the northern Humboldt coast, so a frost product could be applicable for just NE Mendocino (including Legget, Laytonville, Willits, Potter Valley, and Covelo) for one or both mornings.

A strong Pacific ridge will generally remain in control as additional weak fronts attempt to briefly flatten it, introducing more very slim chances for light showers, mainly in Del Norte County. Chances for a wetting rainfall (0.1 inch or higher) only reach 25% to 35% late this week and increase some this coming weekend. There will be periods of rebounding high temperatures between the fronts. /JLW & JJW & EYS

AVIATION...6Z TAFs

Stratus has established itself over a good portion of Humboldt and Trinity counties. IFR levels will persist as a cold front passes through. Chances for LIFR and light drizzle will remain before frontal passage near 12Z Monday. probabilities quickly lower thereafter with lifting ceilings and scattering stratus.

Northerly winds will increase throughout the day Monday, and the coastal terminals will receive wind gusts of 30 kts, and up to 40 kts Monday afternoon before subsiding into the evening.

MARINE

Northerly winds are strengthening in all waters Monday behind a cold front. This round of northerly winds will be on the stronger side, with gusts to 40 to 45 kts. Gale conditions will remain in all zones through Monday night before beginning to slowly subside. Gale conditions will remain in the southern waters throughout the day Tuesday. Large steep and hazardous seas will build 13 to 15 ft Monday evening through Tuesday. Northerly winds will greatly ease Wednesday, but will remain 15 to 20 kts around and downwind of Cape Mendocino through the week and likely longer.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 AM PDT early this morning for PZZ450-470.

Gale Warning from 5 AM early this morning to 4 AM PDT Tuesday for PZZ450-470.

Gale Warning until 10 AM PDT Tuesday for PZZ455.

Gale Warning until 5 AM PDT Wednesday for PZZ475.