textproduct: Eureka

SYNOPSIS

A weakening frontal system will bring isolated showers to the region through Tuesday. Widespread rain is expected Tuesday night into Wednesday followed by lingering showers into Thursday. Mountain snow and coastal small hail is possible Wednesday night and Thursday morning.

DISCUSSION

Rain showers have arrived to the area, with a band of precipitation focused primarily on northern Humboldt and Del Norte being observed. Rain rates have remained light to locally moderate. High resolution models show showers continuing tonight into Tuesday, mainly for Del Norte, Humboldt, and Trinity counties, though a few isolated showers are still possible for Mendocino and Lake. These showers are likely to remain light, and little to no impacts are expected.

A stronger frontal system moves through the PacNW Tuesday night into Wednesday. Southerly winds will increase ahead of the main frontal passage Wednesday morning. Much of elevated terrain of Del Norte and the higher terrain in Humboldt have over 50% chances to see gusts over 40 mph. Localized gusts of over 50 mph are possible over the highest terrain. Lake County may also see strong gusts, with a broad 20% chance for gusts over 40 mph at lake level. The higher elevations, including the Cobb area, have much higher probabilities.

Widespread light to moderate rain is likely across the area. Periods of heavy rain are possible for the North Coast, and especially in the King Range and the mountains of Del Norte and northern Humboldt. Total rain amounts range from around 2.0-3.0" in Del Norte, 1.0-2.0" in Humboldt and Trinity Counties, and 0.25-1.00" in Mendocino and Lake Counties. This will largely be beneficial rain, but some minor impacts (flooding in poor drainage areas and mud/rock slides) are possible in Humboldt and Del Norte with the heaviest rain. Snow levels will drop with this system, down to 5,000-5,500 ft Wednesday morning during the period of most precipitation. This will bring some snow down to Scott Mountain Pass. Snow totals there range from around 2 to 6 inches, depending on how low snow levels drop.

Stratiform rain turns showery Wednesday night into Thursday. Snow levels continue to drop into Thursday, and could be as low as 2,500 ft. While precipitation is likely to be meager by this point, some light snowfall is possible on the highest passes of Highways 3, 36, 199, and 299. Additionally, with much colder air aloft, instability will increase, particularly along the coast. Showers capable of producing accumulating small hail are possible, along with isolated thunderstorms.

Much cooler temperatures are expected Friday morning with widespread near-freezing or freezing temperatures. Temperatures will generally trend warmer as high pressure begins to rebuild into the weekend. JB

AVIATION

VFR conditions continue across much of the area this afternoon. There are a few showers in Humboldt and Del Norte counties this afternoon, but these are mainly staying VFR as well. This is generally how conditions are expected to stay over the next 24 hours. Later tonight there increasing probabilities near KCEC for lower CIGS. However confidence is low on this. The may be a slight increase in showers activity Tuesday afternoon as well. MKK

MARINE

Northerly winds are diminishing this afternoon as a frontal boundary approaches the area. These are expected to gradually turn to the west and then the southwest Tuesday afternoon and evening. Tuesday night into Wednesday these winds increase as the frontal boundary approaches and moves through the area. Models are starting to come into better agreement that the winds will peak in the morning, possibly as early as around sunrise. Currently it looks like there will be some gale force gusts right with the front as it moves through. For now will continue to hold off on any gale watches as it looks very marginal. Wednesday afternoon and overnight winds are expected to remain elevated after they switch to the northwest.

The north to northwest winds are expected to diminish on Thursday briefly before building again on Friday. Generally lower winds are expected for the weekend. Also on Thursday a northwest swell is expected to build into the water bringing waves around 12 feet at 12 seconds out of the northwest. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 7 PM PDT this evening for PZZ470.

Small Craft Advisory until 4 PM PDT this afternoon for PZZ475.