Marine Weather and Tide Forecast for Westhaven-Moonstone, CA

DISCUSSION
A scan of the early morning satellite imagery revels a weak front departing to the south out of the forecast area. A better defined shortwave is also observed working its way southward well offshore of British Columbia. The shortwave will accelerate southward today, working its way over N CA late tonight and through Saturday. Mid to high level clouds will increase throughout the day, while low-level stratus will likely linger near the coast due to weak onshore winds and limited surface heating. This feature and associated cold front will have little impacts other than a few light showers/drizzle and a quick shot of cooler temperatures. A brief window of elevated moisture and instability will pass over Trinity County Saturday morning, but any thunderstorm activity is expected to stay outside the county, with timing falling outside of peak heating hours.

Northerly winds will increase behind the front on Saturday, and gusts to 35 mph along the coast and up to 40 mph in the southern inland areas are probable and forecast. Similar winds can be expected Sunday as a secondary shortwave trough positions southward over the Great Basin region before quickly ejecting to the Four Corners area.

Temperatures will drop some behind the cold front, and low temperatures for some of the interior valleys may reach frost- developing levels Sunday morning and perhaps Monday morning. For Sunday morning, frost will be conditional to the effective clearing of cloudcover and dewpoint temperatures after any light showers that manage to occur. Mid level heights will be on the rise Sunday night with a building ridge, but with drying and clear skies, Monday morning may end up being the colder of the two for some select interior valleys.

A warming trend will develop next week as high pressure builds back in. NBM is showing a 30 to 50 percent probability of the inland valleys exceeding 90 degrees. A couple mostly dry fronts make make it over the ridge next week with little impacts other than some enhanced northerly winds, and perhaps very light precipitation closer to the Oregon border or coastal, light drizzle. JJW



AVIATION
Despite isolated areas of low marine stratus visible on satellite early this morning, all coastal terminals have remained VFR through the night. That said, a short period of IFR ceilings for at least a couple hours this morning remains likely (50% chance)
especially around Humboldt Bay. Any marine influence that does form this morning should clear out to VFR early in the afternoon.
Clearing may be a bit delayed compared to recent days thanks to weaker winds near shore. High resolution models generally imply a stronger but elevated marine layer will form late Friday night into Saturday with possible light drizzle right along shore. /JHW



MARINE
North winds have generals moderated through the night with only very isolated areas maintaining gusts over 21 kts. Winds will continue to calm through the day, especially in the northern waters.
Much stronger winds and isolated marginal gale force conditions will return by late Saturday afternoon and through the end of the weekend. During this whole period, the sea state will be almost exclusively controlled by short period waves with only a very minor northwest swell up to 3 feet. A similar pattern of short periods of calm broken up by periods of moderate to strong north winds will most likely continue through most of next week. /JHW



EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 3 AM PDT Saturday for PZZ455-475.