Cape Mendocino to Point Arena CA out 10 NM Marine Forecast
|Tonight...Se Winds 5 To 10 Kt. Waves W 6 Ft At 11 Seconds...And Nw 4 Ft At 16 Seconds.
|Thu...Se Winds 10 To 15 Kt. Waves W 5 Ft At 10 Seconds...And Nw 4 Ft At 15 Seconds.
|Thu Night...Se Winds 5 To 15 Kt. Waves Se 5 Ft At 6 Seconds...And W 6 Ft At 14 Seconds.
|Fri...N Winds 5 To 10 Kt. Waves W 9 Ft At 14 Seconds.
|Fri Night...Ne Winds 5 To 15 Kt. Waves W 8 Ft At 13 Seconds.
|Sat...Ne Winds 5 To 10 Kt. Waves N 3 Ft At 5 Seconds...And W 5 Ft At 13 Seconds.
|Sun...S Winds 5 To 10 Kt. Waves N 3 Ft At 6 Seconds...And Nw 7 Ft At 17 Seconds.
|Mon...N Winds 15 To 20 Kt. Waves Nw 8 Ft At 7 Seconds...And Nw 9 Ft At 15 Seconds.
| Area Forecast Discussion
National Weather Service Eureka CA
248pm PST Wednesday Feb 21 2024
Lingering showers will dissipate through the afternoon leading to partial clearing overnight. Valley fog is likely through the next several nigheights as interior temperatures drop and skies clear. Mostly dry conditions are expected through the remainder of this week heading into the weekend. A shift in pattern is likely to begin Sunday night as the next storm system approaches Northern California with the potential for more impactful precipitation.
Diurnally driven showers across the CWA (County Warning Area) will continue to dissipate as a weak ridge builds into Northern CA. Coastal areas from the King Range through Crescent City were caught in some training bands of showers this morning and early afternoon, producing an additional few tenths of an inch onto several inches of accumulation over the past several days. Otherwise, conditions are effectively winding down - flood prone rivers including the Eel and the Russian are decreasing below monitor stage, while southerly winds are diminishing. Much drier air at the surface helped to lift low cloud ceilings for some clearing this afternoon.
Aside from some high cirrus sifting into the region from offshore, conditions will remain partly cloudy through this evening. Residual moisture trapped in interior valleys will allow low ceilings and widespread fog to develop overnight and early tomorrow morning as radiational cooling surface temperatures. Low ceilings and fog are expected to lift as much needed sunshine and a surge of WAA (Warm Air Advection - the movement of warm air) drives temperatures into the mid-50's, nearing 60 in coastal areas on Thursday.
Nor PAC water vapor imagery indicates a col point situated between a weakening low off the western CA coast and a deepening cold low developing further west. Highly zonal flow in the central Pacific will inhibit eastward migration of this low. As the upper level low strengthens and becomes cutoff from the parent trough, a dance of the double barrel surface lows will begin in the northern Pacific as the two low centers spin around each other. Outlying bands of frontal instability reaching through the elongated low axis may approach the coast Thursday into Friday, but models are indicating precipitation will remain largely offshore. As mentioned, high clouds are likely to be the only effects of this system, setting the stage for a drier weekend.
High pressure will build in behind this low as it reverses direction and backs offshore. Temperatures are forecast to exceed 60 degrees along the coasts and inland valleys Friday into the weekend, a much needed break to dry out soils. The next chance for precipitation is expected around Sunday night into Monday as a cold upper trough and surface low drops into northern California, indicating the next shift to a more active pattern. Model Quantitative Precipitation Forecast still has some uncertainty on timing, but both the GFS (Global Forecast System) and the Euro are hitting on higher precipitation totals in northern Humboldt and Del Norte counties. Both models are also indicating a rapid drop in mid level temperatures as the trough digs into the PNW. Snow levels will be monitored closely as this system develops.
Southerly wind and seas have generally calmed today with combined seas below 8 feet and gusts below 15 kts. A weak low pressure system stalling over the eastern Pacific will bring a band of stronger southerly wind to the outer waters Thursday into Friday. There is forecast uncertainty depending on how close the low will get, but even higher end models don't show gusts anywhere above 25 kts. Elevated winds will likely persist just long enough for short period seas in the outer waters to reach 6 feet. Otherwise, the sea state will be dominated by weak, mid period northwest swells. A steeper northwest swell up to 10 feet at 13 seconds is expected to build Friday into the weekend just as winds and short period seas fall. Otherwise moderate northwest winds are expected this weekend with another storm with southerly wind possible early next week. /JHW
.EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from noon Thursday to 3am PST Friday for PZZ470-475.