textproduct: Eureka

SYNOPSIS

Dry weather continues through Saturday. Unseasonably warm afternoons and chilly mornings are likely Thursday. Rain and high elevation snow likely returns to the area Sunday.

DISCUSSION

Another warm afternoon is expected today. While high temperatures may get close to daily records for the North Coast, offshore flow will be just weak enough to have those high temperatures fall just short of the records. Coastal areas could see temperatures in the upper 60s or even low 70s a little farther away from the direct coastline. Overnight temps are forecast to be chilly with lows in the 20s and 30s in the valleys and lower elevations with the higher elevations above a stable inversion remaining fairly warm over 50F in some spots.

Agreement is growing on the high pressure/ridging pattern ending Friday. A deep, elongated trough is forecasted to move through the area. Increased cloud cover and a deeper marine layer will lead to more moderated temperatures over NW CA Friday and Saturday. A return of rain is forecasted to arrive sometime between Saturday night and Sunday midday. Generally, rainfall amounts are likely to be minor, but precipitation rates could briefly be moderate to locally heavy. NBM is showing around a 40 to 80% chance for over an inch of rain from Sunday morning through Tuesday morning. The highest probabilities are focused more for the higher elevations in Humboldt, Trinity, and Del Norte counties. Mendocino and Lake counties show less confidence in rain with a 30-60% chance of rain over 0.5" and a 10-25% chance that there is no rain at all, especially for Lake County. Winds for this frontal system do not look to be very impactful, with only a 10-20% chance for southerly wind gusts greater than 30 mph for wind prone areas in Lake County. Snow levels are also likely to remain above 6,000 ft until Sunday night before dropping to ~4,000 ft Monday morning, bringing light snow to the highest passes on Highway 3 and Highway 36.

Forecast uncertainty grows early to mid next week. Some ensemble members are showing a break in precipitation, while others are showing continued pulses of precipitation. That said, the forecast is fairly certain this change in weather will bring much colder temperatures, increased rainfall (which won't be hard after all this dry weather), and mountain snowfall to the area. JB/DS

AVIATION

VFR conditions are expected to prevail for all aerodromes at least through Thursday night. However, a period of visibility reduction with haze will be possible at KCEC and KACV in the afternoon due to the sea spray. Winds will continue to be light offshore flow, shifting to SSW early in the afternoon. There is the potential for a shallow marine layer developing along the coast late Thursday night into Friday as a cut-off low well offshore the California Coast track southward. This will bring increasing mid to high level clouds across NW California on Friday. /ZVS

MARINE

A mid period westerly swell around 8 to 10 feet at 13 to 14 seconds continue building into this morning. A larger westerly swell with longer period near 17 seconds will build Thursday night into Friday, resulting in hazardous conditions to small craft through Friday night. Light to gentle winds are expected to shift to southerly this afternoon, before increase over the weekend in advance of a front, primarily on Sunday. /ZVS

BEACH HAZARDS

A Beach Hazard Statement is in effect from Thursday evening through Friday night due to a moderate risk of sneaker waves along areas beaches. A large swell is forecast to build into the coastal waters Thursday into Friday, with heights around 10-12 feet at 15 to 16 seconds. These high energy will bring a moderate risk of sneaker waves on Thursday, resulting in the potential deadly waves that unexpectedly surge much farther up the beach than previous waves, overtaking unaware beachgoers. Remember to never turn your back to the ocean, and to avoid steep beaches, jetties, outcroppings, and rocks during these events./ZVS

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement from this evening through Friday evening for CAZ101-103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 PM this evening to 3 AM PST Saturday for PZZ450-455-470-475.

Small Craft Advisory until 10 AM PST this morning for PZZ470.