textproduct: Eureka

KEY MESSAGES

* Dry weather is expected this afternoon through Friday. Rain chances return over the weekend.

* Frost and near-freezing overnight temperatures possible for the interior valleys and possibly near the coast each night through the weekend.

* Minor coastal flooding at high tide expected through Thursday around Humboldt Bay.

SYNOPSIS

Cool and dry weather is expected through Friday with additional chances for light rain over the weekend. High tides are likely to cause areas of coastal flooding for areas around Humboldt Bay through Thursday.

DISCUSSION

Dry and cool air continues to build into the area as we remain under a troughing pattern. This is bringing near to slightly below normal temperatures, with most areas seeing highs in the 50s and 60s. A stray 70 is possible in the warmest valleys of Mendocino and Lake Counties. Temperatures this morning ended up slightly above forecast, especially in interior Humboldt and Trinity, as extensive valley clouds filled in. Cloud cover is expected to diminish tonight outside the near-coast river valleys with a similar to slightly colder night possible. Cold nights continue for the coming days with chances for frost and near-to- below freezing temperatures possible for the interior valleys, and even close to the coast. The troughing pattern remains in place for the remainder of the week, but conditions remain dry through Friday. Onshore flow will most likely help a weak, diurnal marine layer reform, especially around Humboldt Bay, as soon as Wednesday night.

The only exception to a dry Friday would be in Del Norte County, where there is roughly a 20% of light rain that currently may only amount to a hundredth or two with the bulk of precipitation to the north. This low off the coast of Oregon moves southward this weekend, though there is some uncertainty on just how much moisture will arrive and how far south the low will drop. There is a widespread 30-50% chance of any measurable rain on Saturday and Sunday for all of NW California. The chance for wetting rain (over 0.1") is around 20%. This system is a cold system, and snow levels may drop to around 4500 to 5500 ft. Moisture is limited by the time snow levels drop, but a dusting of snow in the higher terrain may be possible, including along Highway 3 at Scott Mountain Pass.

While over a week out, long range ensemble members are continuing to signal a shift towards a wetter pattern. Today's model runs are less bold than yesterday's and the highest potential for heavier rain has moved into late next week and into the weekend. Still, some models do show some rain mid next week with about a 50% chance for any measurable rain and a 20% for over a tenth of an inch. This pattern will continue to be watched over the coming days. Stay tuned! /JB

AVIATION...(18Z TAFs)

VFR conditions are being observed at all terminals early this afternoon with interior valley clouds quickly dispersing. Weak offshore flow is expected to hinder a widespread return of marine clouds tonight. Still, some models do show a deep marine layer returning in areas tonight, with around a 30% chance for MVFR ceilings at CEC and ACV. Chances are higher around Humboldt Bay and over the Eel River delta. Some interior valleys may see some intrusion of clouds again tonight, however this will be less widespread than this morning. /JB

MARINE

Strong northerly winds have built into the southern outer waters with gusts near gale force. Winds will remain strong and intermittently push into the inner waters through Thursday evening. Short period seas of 8 to 10 ft are expected with these winds. North winds have remained much more moderate in the northern waters. North winds will persist until early Friday when they diminish into the weekend. Beyond short period seas, various minor mid period westerly swell will augment the sea state through the week. /JHW

COASTAL FLOODING

Water levels Wednesday reached 9.12 ft above MLLW at the North Spit. This brought some minor flooding to low lying areas of King Salmon and the Arcata bottoms. This was with an anomaly of about 1 foot above astronomical tides. The surge models are showing a slightly higher anomaly during the high tide Thursday (at 1:59 PM), and with an astronomical tide of 7.88 ft, this would again push levels near or above 9.0 ft. A Coastal Flood Advisory will be reissued for the high tide on Thursday.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory from 1 AM to 9 AM PDT Thursday for CAZ101>106-109-112.

Coastal Flood Advisory until 3 PM PDT this afternoon for CAZ103.

Freeze Warning from 1 AM to 9 AM PDT Thursday for CAZ110- 111-114.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory until 3 PM PDT this afternoon for PZZ415.

Small Craft Advisory until 3 AM PDT Thursday for PZZ455.

Small Craft Advisory until 9 PM PDT Thursday for PZZ475.