textproduct: Eureka

SYNOPSIS

Some light showers will linger Thursday behind a front. Building high pressure will dry bring dry weather, above average interior daytime highs, and chilly overnight lows.

DISCUSSION

Moderate to locally heavy rainfall (0.3 inch per hour) ended late Wednesday with the passing of the front. Winds will be much lighter today, but some gusty northerly winds will develop this afternoon in Mendocino and Lake County. A chillier airmass has moved in behind the front. Overnight lows will bring chances for interior frost and some freezing temperatures, but values will be close to climatological norms. After the recent rains, and building high pressure, the environment will be favorable for poorly modeled radiational fog over at least the next couple of mornings. The interior valleys that see this fog will have less chances for frost/freeze. The ridge nosing in from the west will warm temperatures nicely, especially in the interior. Chances for daytime highs greater than 65F are high for interior valleys are highest on Saturday (80-90%).

An additional system is possible early next week, but ensembles continue to trend this system northward. Even high- end precipitation amounts (75th percentile) are only showing 0.25 amounts clipping Del Norte County. After the passage of an associated cold front, cooler overnight lows will return Tuesday morning. Precipitation chances are currently not forecast to trend higher until Mid to late next week. JJW

AVIATION...(06Z TAFS)

The heaviest rain continues to taper off early Thursday morning. Winds will also continue to diminish for area terminals. MVFR conditions are mostly expected for coastal terminals into late morning with the chance for some lingering showers into mid morning. Lower clouds (high MVFR to VFR) may also linger for interior valleys into early Thursday afternoon. Mixing and cloud cover should limit the risk for IFR due to fog; however, periods of IFR/LIFR ceilings could occur for interior valleys, such as KUKI. Rain will completely leave the region by late morning.

MARINE

Winds over the coastal waters will continue to diminish and turn westerly and northerly through Thursday. A large W-NW swell will begin to build through the day and reach 15-17 feet at 13-15 seconds Thursday afternoon and evening. This swell may combine with short period wind waves and seas will once again become quite hazardous. A warning for seas may be necessary. At this time, the wind waves appear to dwindle and the swell looks to be the dominant energy. For the remainder of the week, northerly winds and steep wind waves are generally forecast to prevail. Near gale wind gusts are certainly possible downwind of Cape Mendocino. Another large W- NW swell group will propagate into the waters this weekend and may pose a threat for sneaker waves once the shorter period wave groups subside.

BEACH HAZARDS

A large W-NW swell will bring a risk for dangerous surf Thursday afternoon through Friday morning. Breakers from 16 to 20 feet are expected assuming an ideal and average beach profile. Larger breakers will be possible if the swell ends up coming bigger than forecast by GFSwaves. Continuing to call attention to this risk via weather story post and on social media. The swell is too large for sneaker wave criteria and too low to warrant a high surf advisory. A longer period W-NW swell group from 8-12 ft with dominant periods near 16 seconds is forecast to build over the weekend. This swell may pose a greater risk for sneaker waves and continued erosion of beach profiles. Stay tuned.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 AM to 3 PM PST Thursday for PZZ450-455-470-475.

Hazardous Seas Watch from Thursday afternoon through Friday morning for PZZ450-455-470-475.