textproduct: Eureka

SYNOPSIS

Cloudy skies and light showers continue through the evening. Ridging fills in behind the low with warmer temperatures and clearing out skies by mid week.

DISCUSSION

As low pressure proceeds south and inland, diffluent flow is being observed on a synoptic scale with a high amplitude ridge filling into the PACNW behind the large scale troughing pattern. The anticyclonic motion, in sync with the low over our area is pulling moisture through the mid levels. This has resulted in layered cloud cover for much of the CWA with some light showers but most of the precip accumulating in the southern regions, Lake and Mendocino. Chances for thunderstorms on the Trinity horn are around 20% through the evening. There could be a few pop up thunderstorms with lightning tonight. Precipitation is expected to ease with the passing of the exiting low before noon Tuesday.

Drier conditions will quickly return by Tuesday. That said, there is a very slight (< 10%) chance of some weak lingering thunderstorms over the interior on Tuesday. Benign and weak high pressure will build late in the week, bringing slightly warmer than average temperatures but otherwise dry, seasonable, and calm weather. There is chance for the marine layer to finally clear out around Wednesday before rebounding later in the week as a marine inversion reforms under the interior heat.

AVIATION

Fairly widespread MVFR clouds remain across the area. Some showers continue in southern Mendocino and Lake counties. Showers and a few thunderstorms are developing in northeast Trinity county. These should end as the daytime heating diminishes this evening. At the coast and in the valleys CIGs are expected to slowly diminish tonight to IFR. A few pockets of lowers conditions are expected, but these aren't expected to be widespread. Tuesday CIGs are expected to slightly lift, but remain MVFR or possibly even IFR at the coast. MKK

MARINE

Winds are starting to become westerly south of Cape Mendocino, but currently remain south or southwest farther north. These are expected to become more northwest and eventually north tonight and early Tuesday. For these time periods the waves are expected to remain below 10 kt. The waves are dominated by a northwest swell around 7 feet at 14 seconds. There is also a wave around 5 feet at 9 seconds.

Tuesday afternoon northwest winds are expected to increase to around 10 to 15kt. The waves remain dominated by a 3 to 4 foot wave at 12 seconds and a 2 to 5 foot wave around 5 to 8 seconds. This may mix with the local wind driven waves. The winds are generally expected to remain around 5 to 15 kt out of the north through the workweek. Late in the week a system moving by to the north may briefly switch the winds to the west or southwest. Over the weekend high pressure returns and near gale to gale force northerly winds are expected to return. The waves are expected to remain fairly small, around 3 to 5 feet at 10 seconds, through Tuesday. A new swell is expected to build to 4 to 6 feet at 14 seconds on Wednesday. MKK

EKA WATCHES/WARNINGS/ADVISORIES

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