textproduct: Eureka

SYNOPSIS

Another cold night is in store as clear skies persist. A marine layer will likely build along the coast early Sunday with coastal drizzle by the evening. Cool and dry weather will return Monday and Tuesday.

DISCUSSION

WEATHER PATTERN OVERVIEW: Clear skies overnight promoted cold conditions. Just enough fog formed near shore to prevent widespread frost, but many interior valleys saw near freezing conditions despite low cloud and fog formation. Very similar conditions will be expected tonight for far interior locations with lows in the mid 30s once gain, though valley fog will continue to make true frost formation patchy at lower elevations.

Winds quickly turning onshore ahead of a weak trough passage to the north will most likely promote a coastal marine layer to form early Sunday morning. The marine layer lifting through the day may allow for light rain and drizzle just along the immediate coast Sunday afternoon and evening. Rain chances are greatest in Crescent City where there is a 25% chance of wetting rain (> 0.1 inches) and a 90% chance of at least light drizzle. Chances drop by Humboldt Bay where there is only a 50% chance of even light drizzle.

Clearer skies and offshore flow will quickly reassert themselves early next week with another 50% chance of light frost in the interior by Monday morning. Most ensemble members continue to show a cold, cutoff low pressure system impacting the area mid to late next week, though potential timing is very uncertain. At least some rain is very likely, but the range is large (most likely 0.5 to 2.0 inches) because many models focus the system north. Compared to previous model runs, more now show the system staying north of the area (about 50%). Should rain occur, it will focus on the North Coast. NBM shows snow levels of 3000 to 4500 feet on the back end of the system into next weekend, which could bring some of the lowest elevation (albeit very light) snow of the season so far. There is little ensemble support (less than 20% over 45 mph) of any impactful winds with the system. /JHW

AVIATION...(18Z TAFs)

Northwesterly winds have filled in as of 18-19z with VFR conditions expected to prevailing at the coastal terminals. A reduction in visibility from haze/mist at KCEC and KACV brought periods of MVFR/IFR late this morning and could return at intermittent intervals later tonight as cloud cover fills in and ceilings lower. There is a 50% probability that ceilings will be less than 6500ft before midnight at KCEC and 56-60% for KACV. Cloud cover will likely begin to fill in before midnight as well. Look for light rain or drizzle tomorrow by the late afternoon as the marine layer lifts for KCEC and to a less of a chance at KACV with only a 50% chance of light drizzle for the Humboldt bay area, as mentioned in the general discussion. /EYS

MARINE

Northerly winds continue at a moderate rate for the Northern waters and a few knots higher in the Southern waters this afternoon but will build as the fetch moves south. Small Craft Advisory still remains in place for all area waters through the end of the weekend with gusts of 20-30 kts in the Southern outer waters, peaking tonight. Seas remain elevated as steep wind waves combine with large long period WNW swells. Combined seas may reach 12-15 ft this afternoon and evening. Winds ease Sunday as a weak front passes through the area, but northerly winds return behind the front Sunday night into Monday. Combined seas may temporarily drop below 10 ft Sunday night, but are forecast to exceed 10 ft again as winds build. Milder conditions return by Tuesday evening and continue through midweek. /JB /EYS

BEACH HAZARDS

A series of long-period WNW swells will fill in starting Saturday morning. These will pose a moderate risk of sneaker waves through the day Saturday and Sunday. Breaking wave heights may reach 17-19 ft. Be cautious visiting beaches and jetties and remember to never turn your back to the ocean!

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement through Sunday evening for CAZ101- 103-104-109.

Frost Advisory from 2 AM to 9 AM PST Sunday for CAZ103- 106>108-110-111.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until noon PST Sunday for PZZ450.

Small Craft Advisory until 6 PM PST Sunday for PZZ455-475.

Small Craft Advisory until 11 PM PST Sunday for PZZ470.