Cape Mendocino to Point Arena CA out 10 NM Marine Forecast
|Tonight...N Winds 10 To 15 Kt. Waves N 7 Ft At 6 Seconds...And Sw 2 Ft At 19 Seconds. Patchy Fog.|
|Tue...Nw Winds 10 To 15 Kt. Waves N 6 Ft At 5 Seconds...And Sw 2 Ft At 18 Seconds.|
|Tue Night...Nw Winds 5 To 10 Kt. Waves Nw 5 Ft At 11 Seconds... And Sw 2 Ft At 17 Seconds.|
|Wed...S Winds 5 To 10 Kt. Waves Nw 5 Ft At 10 Seconds...And Sw 2 Ft At 16 Seconds.|
|Wed Night...S Winds 5 To 10 Kt. Waves W 7 Ft At 13 Seconds... And Nw 3 Ft At 18 Seconds.|
|Thu...Nw Winds 10 To 15 Kt. Waves W 13 Ft At 15 Seconds.|
|Fri...Nw Winds 10 To 20 Kt. Waves Nw 12 Ft At 14 Seconds...And Sw 2 Ft At 18 Seconds.|
|Sat...N Winds 15 To 25 Kt. Waves N 7 Ft At 8 Seconds.|
| Area Forecast Discussion|
National Weather Service Eureka CA
248pm PDT Monday September 21 2020
Light rain is forecast to spread across Del Norte and northern Humboldt counties Wednesday night into Thursday, with much lower rain chances expected elsewhere. Late in the week, warmer and drier weather will develop across the region and persist into early next week.
A minor upper disturbance was located offshore from NWRN CA during Monday afternoon and was yielding patches of high clouds spreading downstream across the coast. Farther northwest, a strong upper low was centered over the western Gulf of Alaska. A piece of that feature is forecast to dig southeastward toward coastal OR/WA by Wednesday night, which will aid in driving a surface frontal boundary toward NWRN CA. Frontal rains will develop and spread across Del Norte and northern Humboldt counties Wednesday night into Thursday. At this time, storm total rainfall is expected to range from a quarter inch near Humboldt Bay to 0.75 inch in north-central Del Norte county. Farther east and south, very little if any rainfall is expected over Mendocino and Lake counties north into eastern Trinity county.
Rain is forecast to dissipate during Thursday afternoon followed by clearing skies across the interior. Radiational cooling accompanying the clear skies may support Friday morning temperatures sufficient for locally patchy frost across wind sheltered areas in Trinity county. Otherwise, a tightening surface pressure gradient late in the week will support breezy north winds...particularly on Sunday. In addition, model guidance is in good agreement showing a large upper ridge developing over the western CONUS this weekend into early next week. Interior valley highs in the 90s to around 100 will subsequently be possible Sunday and Monday.
While winds and seas have continued to gradually diminish across most of the area, have hoisted a short fuse Small Craft Advisory for the outer waters S of Cape Mendocino to account for residual borderline wind and seas downwind from the cape. This is also a better fit with the ongoing advisory from MTR. Winds in this zone will eventually diminish as well, but not until later tonight and early Tuesday. Winds are expected to back to southerly N of Cape Mendocino by Tuesday afternoon ahead of an approaching front, with southerlies area-wide by Wednesday. These winds will increase to advisory-level speeds by midday Wednesday across the N outer waters. Winds will shift back to northerly by Friday.
A large, early season swell is expected to move into the waters on Thursday. The forerunners will move in Wednesday evening and overnight with wave heigheights peaking on Thursday. This could bring a threat for sneaker waves, but they will be coincident with the stronger southerly winds, so it is not expected to be a big threat. Models are remaining quite consistent in these waves peaking around 14 feet at 15 seconds. The waves may have more run- up than normal due the summer beach bathymetry. /SEC
.EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...None.