textproduct: Eureka

SYNOPSIS

Calm weather will continue this weekend. Persistent light to moderate rain will arrive Monday and Tuesday, mostly focused on the northern half of the area. Stronger rain spreading further south in likely later in the week.

DISCUSSION

Broad high pressure and gentle offshore flow will continue through the weekend. This will promote a very shallow but patchy marine layer along shore with shallow fog overnight. During the day, unseasonably warm conditions will continue.

There is high ensemble confidence that a wetter pattern will finally return early next week, bringing the first wetting precipitation for December across NW California. A weak to moderate but consistent atmospheric river will most likely (80% chance) impact the area beginning late Monday through mid week. There does remain a 20% chance that rain will remain north of the area with little precipitation for the North Coast, but this chance has consistently decreased in recent model runs.

There is strong indication that conditions will remain much warmer than normal during the wet period, eliminating any winter weather concerns and generally limiting the thunderstorm or higher end rain rate potential. Rain will be mostly focused along the North Coast. Although much more rain than recently, rain amounts will be very typical for this time of year. Most likely rainfall at lower elevations along the North Coast between Monday evening and Wednesday will be between 1 and 2 inches with enhanced rain amounts at higher elevations of 2 to 4 inches. Rain amounts will be much less for the southern half of the area with less than 0.5 inches of rain most likely in Lake County and around the Russian Valley. Given recent dry weather, even rain rates aligning with model outliers will most likely result in little flood risk.

Beyond rain, enhanced southeast wind will briefly arrive alongside the rain. Similar to the rain though much windier than any conditions over the past several weeks, conditions will generally be typical for December. Peak wind gusts at lower elevations will most likely be 25 to 35 mph with only a 20% chance of impactful gusts over 45 mph on high coastal ridges. Winds gusts will most likely be strongest Monday and Tuesday.

There is generally high (80% of ensemble members) that a wetter pattern will continue through the end of December. Long range forecasts have placed a higher risk for a moderate to strong atmospheric river near the end of next week. This could translate into heavy rainfall of 2 to 6 inches and wind gusts over 60 mph. There remains, however, very high ensemble variability with a large possibility that any stronger storms continue to stay north of the area. /JHW

AVIATION...(06z TAFs)

MVFR visibility persist at ACV, while prevailing VFR conditions at CEC. A southerly stratus surge is expected early this morning(10Z), with low clouds and patchy fog charging up near the coastal area. Expect IFR conditions at the coastal terminals between 11Z-15Z, followed by MVFR/VFR with visibility reduction in BR/HZ. VFR condition is expected to prevail at UKI. Winds remains light./ZVS

MARINE

Wind shift to southerly overnight. Generally light to gentle southerly winds is expected today, before gradually increasing on Sunday. Conditions are expected to worsen Sunday night through Monday as a cold front moves through, especially north of Cape Mendocino. Moderate to strong southerly winds are likely north off Cape Mendocino, with the strongest over the northern outer waters. Lighter winds are expected south of Cape Mendocino. Winds will gradually to diminish in the wake of the front Monday evening. A mid-period westerly swell around 8 to 10 feet is expected to build in Monday night into early Tuesday morning. /ZVS

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None.