textproduct: Eureka

SYNOPSIS

Midlevel clouds and moisture will continue to build overnight with light drizzle near the coast Monday morning. Conditions will clear again Tuesday with light rain later in the week.

DISCUSSION

Widespread fog has been steadily forming in the valleys of NW CA. Onshore winds have pulled moist but cool air all across NW California as evidenced by the building midlevel clouds and robust interior valley fog.

A weak trough is currently passing to the north of the area providing enough lift for light rain and potential drizzle along the coast and in some near coastal valleys. No precipitation (or even much cloud cover) will be seen in Mendocino and Lake Counties, with drizzle focused further north. There is little chance of any wetting rain (>0.1"), yet some rain has already been reported at this point in and around Crescent City. Clearer skies will bring another chance (50% or so) of frost for interior Valleys early Tuesday, but valley fog will continue to make any frost patchy at best.

Ensembles have come into better agreement concerning a potential system later in the week and now generally show the bulk of the system staying further north of the area and weaker than early runs suggested. Most deterministic models now have only a week cold front crossing the area around Thursday or Friday with minimal agreement between the Euro and the GFS models. While such a front would likely pull moisture and light drizzle onshore, ensemble spread now shows only a 20 to 40% chance of light wetting rain along the North Coast with less than a 10% chance of 0.5 inches of rain anywhere. A moist and drizzly pattern will likely continue into the weekend, but potential for meaningful wind or precipitation remains low. Long range outlooks from the CPC show warmer and drier than normal conditions are most likely to persist through the first week of December. /JHW

AVIATION

A weak frontal boundary is bringing some light rain or drizzle to the Oregon coast this morning and at times this may extend down into Del Norte and even briefly into Humboldt county. This is bringing mainly MVFR conditions. Inland valleys are seeing widespread low clouds and fog including KUKI. Monday the coast is expected to clear out fairly quickly, but the inland valley fog is expected to be stubborn once again. This will likely take until mid to late morning to clear. Breezy northerly winds around 10 kt are expected Monday afternoon along the coast. Monday night there is expected to be some valley fog again, although confidence is low on how widespread it will be and if it will make it into KUKI. The coast is expected to remain clear with offshore flow. MKK

MARINE

Winds have diminished as a very weak frontal boundary approaches the area. In the north winds have turned southerly, but remain generally less than 10 kt. Monday the front moves through and northerly winds return and increase across the area. Models have trended slightly weaker with these winds, but they still look to be around 15 to 20kt. The swell is gradually dropping, but looks to be dropping slower than expected in the southern waters. So have extended the small craft advisory through Monday evening to highlight the northerly winds as well. There may be a short break between these two, but at this point it looks like the waves will remain close to ten feet until the winds increase.

Tuesday and Wednesday are generally expected to see fairly light winds. Wednesday afternoon these are expected to start becoming southerly again as a frontal boundary approaches the area. The models continue to struggle with the strength of the system on Thursday and how far south it will come. In general it looks like the models have shifted it slightly to the north making the southerly winds a bit lighter. They generally look like they will still peak around 20 kt in the northern outer waters with lighter winds farther south. Some of the models to show a lighter scenario than this. Friday stronger northerly winds are expected to return and models are in fairly good agreement on this. For the weekend the models have trended towards keeping the northerly winds in place. Some of the models show these northerly winds fairly strong at around 30 kt.

The swell is expected to continue to diminish Tuesday to around 6 feet at 12 seconds. Wednesday these swell heights drop to around 4 to 5 feet at 11 seconds. The wind driven waves are expected to diminish Tuesday night setting up a very calm day on the water for Wednesday. Total wave heights look to be around 4 feet with a dominant period of 12 seconds. The next swell is expected to build in Thursday morning, but this is now looking fairly small. MKK

BEACH HAZARDS

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PST early this morning for PZZ450-470.

Small Craft Advisory until 2 AM PST Tuesday for PZZ455.

Small Craft Advisory until 1 AM PST Tuesday for PZZ475.