Cobb, CA Weather

Key messages

* Dry weather through Friday. Light 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 Saturday.

* 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 stream 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 are again close to frosty conditions. That said, clouds building from the south as well as a reforming marine layer will likely inhibit any widespread frost formation by morning. The troughing pattern remains in place for the remainder of the week, but conditions remain dry through Friday. Increasing upper level clouds will likely aid in particularly cool interior highs barely reaching the 60s. Onshore flow will most likely help a weak and diurnal marine layer form through the end of the week.

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% focused on the North Coast. 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. Essentially every day between November 14th and 90th currently show a 30% chance of wetting rain, suggesting high confidence in a wetter pattern but high timing uncertainty. This pattern will continue to be watched over the coming days. Stay tuned! /JB, JHW

Aviation

Weak onshore flow and slightly less instability has allowed for a weak and inconsistent marine layer to form overnight. This layer will bring a variable 50/50 chance of IFR ceilings to coastal terminal through sunrise. QUick clearing to VFR is expected early Thursday morning followed by a slightly stronger marine layer overnight. Otherwise VFr conditions persist for the interior aside from some patchy valley fog. /JHW

Marine

Strong northerly winds persist in the southern outer waters with some steep waves up to 8 feet pushing closer to shore. Winds will remain strong though more isolated to the outer waters through Thursday night. 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.

Watches, warnings and advisories

CA: Frost Advisory until 9 AM PDT this morning for CAZ101>106- 109-112.

Coastal Flood Advisory from 1 PM to 4 PM PDT this afternoon for CAZ103.

Freeze Warning until 9 AM PDT this morning for CAZ110-111- 114.

NORTHWEST CALIFORNIA COASTAL WATERS: Coastal Flood Advisory from 1 PM to 4 PM PDT this afternoon for PZZ415.

Small Craft Advisory until 9 AM PDT this morning for PZZ455.

Small Craft Advisory until 9 PM PDT this evening for PZZ475.