textproduct: Eureka

SYNOPSIS

Near-freezing to freezing overnight low temperatures are expected again Saturday morning, although most areas will be slightly warmer. Increasing clouds are expected Saturday afternoon with rain returning Sunday afternoon or evening and continuing into next week. Drier weather is expected for late in the week.

DISCUSSION

High pressure is over the area and winds are starting to diminish as the ridge axis moves overhead. Tonight as the ridge axis moves overhead and then off to the east. This will diminish easterly winds and may allow some coastal stratus to develop and move onshore later tonight. This is expected to keep temperatures in the upper 30s and should limit the potential for frost. Farther inland in Trinity county as well as portions of Mendocino and Lake counties temperatures will likely be closer to freezing. Saturday afternoon temperatures may warm a few degrees more than Friday.

An upper level low approaching the area will start to increase high clouds Saturday afternoon and evening. This low slowly moves towards the area Saturday night and Sunday. At some point this will push a front onshore and bring some rain to the area. Now it looks like this will be point Sunday afternoon at the north coast and move farther inland in the evening and overnight. The has been trending slower, but for the last couple runs it seems to have settled on Sunday afternoon and evening. Rainfall is expected to be heavier on Monday and Tuesday. Rainfall totals are expected to range from a low end (10th percentile) of 0.25 to 1.5 inches to a high end (90th percentile) of 1.25 to 4 inches. The highest amounts will be over the higher terrain from Cape Mendocino south into northern Mendocino county and inland to South Fork mountain. Tuesday afternoon the low is expected to move over the area bringing the potential for afternoon thunderstorms. Southerly winds with this system are expected to increase as well, gusts to 30 to 35 mph are possible. They could even be slightly higher over the higher terrain. Snow levels generally are expected to remain over 5,000 feet, but this still may bring snow to the Trinity Alps and other mountains.

Thursday dry weather is expected to return. There may be a few showers in the morning if the low slows down anymore. Frost or freezing conditions are possible Thursday and/or Friday morning with the cold air associated with the upper low. Temperatures are expected to gradually warm up into the weekend. MKK

AVIATION...(18Z TAFs)

VFR conditions are likely at least through this evening at all terminals. Gusty northerly winds are possible again at the coastal terminals, with gusts possibly exceeding 15 kts. These winds will ease shortly after sunset. Depending on how much offshore flow weakens tonight, stratus may form near the coast. Some models are showing a southerly wind reversal developing off the Del Norte coast tonight, which would push any stratus towards CEC. NBM shows around a 40% chance for at least MVFR conditions at CEC and a 20% chance at ACV. Should stratus develop and impact the terminals, LIFR conditions are likely. Any stratus and fog will likely lift shortly after sunrise. JB

MARINE

Northerly winds have generally subsided today, though some areas of 15 to 20 kt gusts are possible in the outer waters and the lee of Cape Mendocino through this evening. Seas remain steep at around 6 to 8 ft at 8 seconds. These will continue to subside as winds ease tonight into Saturday. A frontal system moves through the area Sunday morning. Winds will increase and turn southerly. Wind gusts are forecast to peak at around 20 to 25 kts, but there is a low-end chance (20%) for gale force gusts Sunday and Monday in the outer waters. Wind speeds and direction is highly dependent on the track of the low, which is currently forecast to move near or through the waters Monday into Tuesday. A mid-period west swell will also arrive Monday, peaking at around 8 to 10 ft at 12 seconds. Winds and seas gradually subside late Tuesday into Wednesday as the low moves out of the area. Stronger northerly winds return late next week behind this low. JB

EKA WATCHES/WARNINGS/ADVISORIES

CA... Freeze Warning from 1 AM to 8 AM PDT Saturday for CAZ108- 116-117.

Frost Advisory from 1 AM to 8 AM PDT Saturday for CAZ110- 114-118.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until noon PDT today for PZZ470.

Small Craft Advisory until 6 PM PDT this evening for PZZ475.