textproduct: Eureka

KEY MESSAGES

* Colder temperatures with chances for interior frost this week.

* Chances for isolated light showers and rain this week.

SYNOPSIS

A cold front arrives today keeping temperatures lower for the inland valleys. Coastal areas can expect minimal warming as well through the remainder of the weekend. An area of low pressure will stall off the CA coast and will bring a period of unsettled weather.

DISCUSSION

A trough and area of low pressure will bring a stretch of cooler conditions. Temperatures today will struggle to reach the low to mid 80s. The low bringing the cold front will cutoff from the flow and stall somewhere off the central to southern CA coast through the week. Unsettled weather consisting of some initial light showers and drizzle will arrive with the passing low Monday. Any accumulation from this initial round will be very light.

As the low cuts off and drifts by, wrap around moisture will begin to band northward over the N CA region. Coverage will again be limited, but some rainfall accumulation is possible, particularly south over Lake and southern Mendocino counties. There are a lot of unknown variables from uncertainty in the position of the stalling cutoff low, but the low looks to dip enough south to tap into some subtropical moisture. If this occurs, more productive showers may develop mid to late in the week. There will also be some dynamics with the low that will bring a thunderstorm potential, though chances are currently low, and mainly for the described southern areas.

Seasonably cold overnight lows will return starting Monday morning, brining back chances for interior frost and sub subfreezing temperatures for the interior. There is currently another chance for light rainfall over next weekend.

AVIATION...6Z TAF

A shallow marine layer will continue to bring LIFR conditions with fog. A weak wind eddy off the North Coast will bring another day where clearing may be limited with shallow stratus and LIFR conditions lingering. An approaching area of low pressure will deepen the layer and weaken the inversion late Sunday. This will likely allow for improvement in both VIS and CIGs and perhaps a period of scattering to VFR, through chances for ceilings less than 500 ft are currently 30 to 50% through Sunday night. Inland terminals are expected to have VFR conditions with NW winds funneling through channels or gaps in the terrain through the afternoon.

MARINE

Northerly winds increase across the waters while the northern inner waters north of Cape Mendocino remain light. Short period seas of 7 to 9 ft will bring conditions hazardous to small crafts through Sunday afternoon. An approaching area of low pressure will quickly calm the northerly winds Sunday night. A brief southern wind shift will occur Monday around the low. A mid to long period northwest swell of 10 to 13 ft will arrive Monday night. A small long period south swell up to 3 ft will also exist in the waters through next week. The northerlies will increase some Tuesday for mainly the outer waters.

FIRE WEATHER

An area of low pressure will move down the CA coast early next week and will stall off CEN CA through late will. The pressure gradient will increase in advance of the trough, bringing stronger winds Sunday afternoon, particularly over the ridges and through terrain gaps. The moistening NW flow will quickly improve minimum RH and overnight recoveries. Showers will be possible starting Monday with moisture wrapping northward around the low. Chances of wetting rainfall are currently low, but the position of the stalling low may allow for higher chances early next week. The best chances for wetting rainfall, up to 45% currently exist closer to the low over southern Mendocino through Lake County through late week. There will be instability with the low. Chances for thunderstorms over land are currently low (less than 5%) for the described southern zones, but the forecast will have to be watched if the low tracks farther south and taps into some sub tropical moisture.

BEACH HAZARDS

An incoming mid to long period swell is forecasted to arrive Monday evening into Tuesday night. While the swell is not the usual signal of a sneaker wave threat due to its mid-period characteristic (14-16sec). That said, an increased threat of sneaker waves is possible due to minimal short period seas in the waters. These conditions could allow for a larger signal of set behavior allowing for long breaks in wave groups that could rush up the coastline. DS

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 PM PDT this afternoon for PZZ470-475.