textproduct: Eureka

KEY MESSAGES

* Strong northeast winds will persist Sunday 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 in Trinity 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 event he coast clear. Conditions will clam Monday allowing for a widespread frosty morning.

DISCUSSION

A strong cold front has passed east of the area over the last 24 hours. As the upper level trough associated with the front continues to dig south, a strong pressure gradient has formed along shore. Strong north winds are ongoing close to shore with gusts near 30 mph. More stable air will allow winds to weaken overnight. In the calmest valleys, some isolated frost is possible by early morning Sunday, but winds will limit its extent. Frost is most likely around Hayfork and some sections of Highway 36.

Winds will turn more northeast and rapidly reform during the day Sunday. The highest exposed ridges in Humboldt and Del Norte and areas along shore will again see gusts around 35 mph with calmer winds in sheltered terrain. Cool but dry air will continue to stream into the area with highs mainly in the 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 in the morning by Monday (60% chance of a freeze for eastern interior valleys). Even the coast has good chances of lows in 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 likewise form back up with some shallow stratus possible by Tuesday. Ensembles remain dry throughout the extended forecast period (next 10-14 days), though much weaker high pressure will generally result in more seasonable temperatures. /JHW

AVIATION...06z TAF

Strong north winds gusts up to 30 kts at coastal terminals have kept marine clouds scattered out, allowing for VFR conditions all across the area. Winds will weaken overnight but resurges tomorrow afternoon with gusts again over 30 kts by late afternoon. Some low level windshear is possible along the coast with northwest winds at the surface but northeast winds around 1 to 2 kft. Otherwise, VFR conditions will persist. /JHW

MARINE

Gale conditions are ongoing in all waters with some gusts as high as 40 kts in the lee of Cape Mendocino. North winds may briefly pull back from inner waters this morning but even then gusts will remain strong. Winds will resurge and push back close to shore by late 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 next 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 day Sunday. Much weaker winds 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 build through Sunday, peaking Sunday 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 Sunday 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, Sunday, and Monday.

North Spit high tide estimates: Today: observed to peak at 8.57 ft at 12:12 P.M.; Sunday: 8.8 ft at 12:32 P.M.; Monday: 8.6 ft at 1:01 P.M.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement from 4 AM PDT early this morning through Monday afternoon for CAZ101-103-104-109.

Freeze Warning until 9 AM PDT this morning for CAZ108.

NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 4 AM PDT early this morning for PZZ450- 455.

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