textproduct: Eureka

KEY MESSAGES

* Light to moderate rain is expected today, mainly in Humboldt and Del Norte counties.

* Valleys of eastern Mendocino and Lake counties are forecast to see near freezing or freezing temperatures again this morning.

* Minor coastal flooding expected Monday through Thursday at high tide, mainly around Humboldt Bay.

SYNOPSIS

A weak front will continue to bring some light to moderate rain to mostly Humboldt and Del Norte counties today. Farther south chilly temperatures are expected again this morning in the eastern valleys of Mendocino and Lake counties. Cool and mainly dry weather is expected Tuesday and Wednesday with another chance for rain late Thursday and Friday.

DISCUSSION

A weak cold front will clip Northwestern California this morning. Light to moderate rain will move through Del Norte and Humboldt counties this morning with frequent to intermittent showers continuing into the afternoon. Showers are anticipated to linger into Monday. It is possible there will be a thunderstorm or two with these showers early this morning, but the instability looks pretty limited. Rainfall amounts are expected to be the highest in Del Norte County with over 0.75 inches expected in the mountains. Rainfall is expected to be less than a quarter inch by the time it makes it to the Humboldt Bay region and the King Range. Farther inland, the Trinity River Valley from Orleans to Hoopa and Willow Creek is expected to see less than a quarter inch. This rain band is forecast to quickly dissipate as it moves further inland. Only a trace to a few hundredths is expected in Trinity, Mendocino and Lake counties, although the northern mountains of these counties may see a bit more. The cloud cover and cool airmass associated with this trough and front is expected to keep highs in the 50s to low 60s.

Monday night and into Tuesday, the upper level trough remains in place, however most of the rain showers are expected to come to an end. Tuesday and Wednesday, the upper low is forecast to remain stationary bringing a mix of sun and clouds. It is possible that a few showers will develop in the afternoons if a shortwave happens to be moving around the trough. High temperatures are expected to remain in the upper 50s to low 60s both Tuesday and Wednesday. Some frost is possible in the valleys if any of them manage to remain clear overnight. Fog is likely in many of the areas closer to the coast.

Thursday through Saturday the upper level trough is expected to remain over the area. This is expected to keep temperatures cool, generally in the 50s to low 60s for the interior valleys. Some rain is expected, but at this point the probabilities for a half inch in 48 hours remains less than 50 percent. The Atmospheric River Ensemble tools also hold off on any strong moisture plumes until the 3rd or 4th of November. MKK

AVIATION...06Z

A band of light to moderate rain will move through Northwest California early this morning. Rain will mostly just affect terminals of Del Norte and Humboldt counties today, with MVFR ceilings and diminished visibility during rainfall. Showers then will affect these same coastal terminals through most of the day with more frequent showers for Del Norte County. MVFR ceilings will lift into the afternoon for most coastal terminals with generally westerly winds in the afternoon and evening. General cloudiness will move across the region through today with mostly westerly winds dominating. VFR conditions are anticipated for most interior terminals.

MARINE

Southerly winds along an incoming front will continue and expand along shore south of Cape Mendocino early this morning. A northwest swell is also building to around 7 feet at 11 seconds tonight. Winds gradually become more westerly early this morning as an area of low pressure moves by to the north. Winds turn northerly again this afternoon and overnight strengthening Tuesday and Wednesday. Northerlies are anticipated to reach 15 to 25 kt by Tuesday afternoon. These are expected to be strongest in the southern waters. North winds look to peak early on Wednesday before starting to diminish once again late in the week. MKK

COASTAL FLOODING

Water levels this morning only reached around 8.7 ft above MLLW at the North Spit. This fell below the 8.8 where flooding typically starts. This was with an anomaly of 1.1 to 1.2 feet above astronomical tides. The surge model shows a similar anomaly on Monday, although the southerly winds could increase this slightly. So with an astronomical high tide of 7.8 feet on Monday, expect water levels will reach 9.0 or 9.1 and cause some minor flooding. So have issued a coastal flood advisory.

Tuesday the winds start to turn back to the north. This may start to diminish the anomaly or keep it steady. This will be the highest astronomical tides, and highest chances for coastal flooding, are forecast to be on Tuesday and Wednesday of next week at 8.04 ft and 8.06 ft, respectively. This will likely bring at least minor coastal flooding and possibly moderate coastal flooding. This will mainly be around Humbodlt Bay with little expected outside the bay unless there are large waves. Arena Cove is also expected to see water level reach the highest astronomical tide levels. Waves are only expected to be around 6 to 7 feet at 11 seconds so am not expecting impacts on the Mendocino coast at this point, but this will need to be monitored. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... Coastal Flood Advisory from 10 AM this morning to 2 PM PDT this afternoon for CAZ103.

Frost Advisory until 9 AM PDT this morning for CAZ110-111- 114-118.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 10 AM this morning to 2 PM PDT this afternoon for PZZ415.