textproduct: Eureka

KEY MESSAGES

* Strong northeast winds will persist this afternoon/evening with gusts over 30 mph along exposed ridges and headlands in Humboldt and Del Norte.

* Clear skies and cool air will enable extensive frost and freezing conditions for Trinity, Northeastern Mendocino, Northern Lake, and interior Humboldt Monday morning.

* More seasonable conditions this week, but no wetting rain forecast for the next 10 days.

SYNOPSIS

Strong north winds will persist today, helping to keep even the coast clear. Conditions will calm Monday allowing for a widespread frosty morning.

DISCUSSION

An upper level trough continues to dig south, continuing a strong pressure gradient along shore. Winds have turned more northeasterly today, especially inland. The highest exposed ridges in Humboldt and Del Norte and areas along shore will again see gusts around 30 to 35 mph with calmer winds in sheltered terrain. Cool, but dry air will continue to stream into the area with inland highs mainly in the 60s to 70s. Winds will also keep marine air scattered out near shore, allowing for mostly stratus free skies.

As winds weaken, clear skies and dry air may allow for freezing conditions Monday morning. A Freeze Warning has been issued overnight tonight into early Monday morning for southern Trinity County, NE Mendocino County, and northern Lake County due to models indicting a 60 to 80 percent chance of freezing morning temperatures for Hayfork Valley, the Hwy 36 corridor from Mad River to about Forest Glen and down to Ruth, Round Valley (including Covelo), and Northern Lake (around Gravelly Valley Airport). A Frost Advisory has also been issued for northern Trinity County, interior Humboldt and northwestern central Mendocino with many colder valleys in the region showing a high probability for low temperatures of 36 degrees or less by early Monday morning. Even the coast has good chances of lows near 40, the coldest of the year so far.

Conditions will gradually warm through the week under the influence of weak high pressure. A marine layer will likely reform by Tuesday morning with some shallow stratus possible. Ensembles remain dry throughout the extended forecast period (next 10-14 days), though much weaker high pressure will generally result in more seasonable temperatures. /JLW /JHW

AVIATION

VFR conditions are anticipated for terminals in Northwest California. Gusty northwesterly winds will continue into this evening for coastal to near coastal terminals. General offshore flow overnight will aid in keeping stratus from forming around coastal terminals, keeping conditions VFR.

MARINE

Gale conditions are ongoing in all waters with some gusts as high as 40 kts in the lee of Cape Mendocino. Winds have surged back close to shore and will continue late this afternoon and into the evening. Short period seas remain steep and hazardous in excess of 12 feet. Winds will quickly pull back from shore by early Monday morning with gentle winds build close to shore and moderate winds in the outer waters by Monday afternoon. Short period sea will gradually fall in response. In addition, a long period swell up to 5 feet at 20 seconds is building through the day Sunday and adding to a chaotic sea state. /JHW

FIRE WEATHER

After a prolonged heat wave last week, cold air has helped quickly drop fire danger with ERC values approaching the 60th percentile by early this coming week. That said, heavier fuels remain dry and gusty northeast wind along side still dry RH will maintain enhanced fire danger at least through the rest of today. Much weaker winds are anticipated for the rest of the week, alongside generally seasonable conditions will limit fire danger.

BEACH HAZARDS

The first long period swell of the season is currently building in. The west-northwest swell has arrived to Northern California with a period around 22 seconds. The swell will continue to build today, peaking this afternoon and evening at around 5 feet at 19 seconds. This very long period swell will result in a heightened chance for sneaker waves and run-ups of unusual size through Monday evening. A beach hazard statement has been issued for Sunday morning through Monday midday as a result.

While the threat for sneaker waves will be persistent throughout today and Monday, the highest risk is expected during periods of incoming tides. With high tides along the California coast at around 11am to 1pm Sunday and Monday along N CA coast. A positive tidal anomaly is yielding tides around 1-1.5 feet higher than predictions on top of higher than usual tides, adding to the threat.

COASTAL FLOODING

A new moon lunar cycle is causing higher than usual tides. A positive tidal anomaly of 1-1.5 feet will yield high tides that will be near or even reach advisory levels of 8.8 ft for Humboldt Bay today, and Monday.

North Spit high tide estimates: Today: peak was 8.71 ft at 12:24 P.M.; Monday: 8.6 ft at 1:01 P.M.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement through Monday afternoon for CAZ101- 103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 9 PM PDT this evening for PZZ450-455.

Gale Warning until 2 AM PDT Monday for PZZ470-475.