textproduct: Eureka

SYNOPSIS

More widespread rain and mountain snow is expected Saturday. Sunday the showers are expected to come to an end as the cold air moves in. A chilly start to the week is expected with near- freezing temperatures possible in the colder valleys. Some additional light rain is possible again Wednesday.

DISCUSSION

The next upper level low is rapidly approaching the coast while the current trough continues to bring showers to the area. There are expected to be some showers around in the morning, but a more significant round of rain is expected to move onshore in the afternoon. This is expected to first move onshore on the Mendocino coast and southern Humboldt coast in the afternoon and spread north and east later in the afternoon. This is expected to bring a period of heavier rain. The surface reflection of this upper low is expected to bring some stronger winds as well. Gusts of 35 to 40 mph are expected along the Mendocino coast and over the higher mountains of Mendocino and Lake counties. Coastal Humboldt may also see some stronger winds with gusts of 25 to 40 mph. The showers are expected to continue overnight as the low moves over Mendocino county. There is quite a bit of cold air aloft and this will produce some instability and this may be enough to produce some thunderstorms. The cold air aloft may produce some small hail, also mainly in Mendocino county. Instability is limited so am not expecting too much accumulating hail and it will likely be pea sized or smaller. Snow levels are expected to drop to 3500 to 4000 feet in Mendocino and Lake counties in the evening and overnight. This is expected to be bring 5 to 10 inches of snow over 5,000 feet. The models have slowed down the departure of the low and now the low center isn't expected to move across Mendocino county until Sunday morning.

Sunday night into Monday the low finally moves out of the area with cold air lingering. This is expected to be the coldest morning in the mountains, but there may be quite a bit of moisture around that keeps the valleys cloudy and therefor warmer. Still there will be the threat for a frost or freeze. Monday afternoon high temperatures are expected to mainly be around 60 degrees. Monday night into Tuesday morning will likely be the colder morning for the valleys, although there is still some uncertainty on the coverage of freezing temperatures due to the potential for some lingering clouds.

Wednesday another weather system is expected to bring more clouds back to the area and some light rain mainly in Humboldt and Del Norte counties. This will keep high temperatures mainly in the 50s once again. The NBM is showing around a 50-70% chance for wetting rain (>0.1") for Del Norte and Humboldt Wednesday, with much smaller chances inland and south into Mendocino & Lake. The chance for over 1" is low, around 30% in the mountains of Del Norte, and near zero elsewhere. Drier weather is expected to return for the remainder of the work week. MKK

AVIATION...(06Z TAFs)

Post frontal conditions are expected after the last of convective showers Friday evening. LIFR conditions lingered the longest at KCEC until around 02z which makes sense due to the nature of cyclonic rotation and the southerly winds with storm motion from south to north. KACV has faired a bit better with mostly MVFR and periods of VFR with cloud base 5000-7000ft. For the coastal terminals there is the possiblility of a few hours of LIFR conditions overnight though there is disagreement between models. The timing of the next frontal push will likely be a few hours before noon on Saturday. KUKI saw much action with CB and VCTS as thunderstorms occasionally moved through Mendocino and Lake counties. There is at least a 20% probability for lightning over most of the area Saturday by the late afternoon and early evening hours, particularly in southern Mendocino and Lake counties. KUKI could see more TS activity around 00z Sunday if areas like Sonoma, with higher probabilities of lightning and thunderstorms, lurch into Lake and southern Mendocino from the south/west. /EYS

MARINE

High resolution models are signaling near Gale force winds as the next low fills in behind the exiting low pressure system that brought erratic winds and lightning to the area for the past few days. The timing of the next system could span Saturday morning through late Saturday night into Sunday morning. The southern waters in particular will get most of the wind with some of the wind energy translating into the northern inner and outer waters. A small craft advisory has been hoisted to highlight the hazards. This will be a short duration event so the wind wave response will be minimal. A Marine Weather Statement is also in play to bring attention to erratic gusts and the potential for lightning and small hail. /EYS

EKA WATCHES/WARNINGS/ADVISORIES

CA... Winter Weather Advisory from 5 PM Saturday to 11 PM PDT Sunday for CAZ107.

NORTHWEST CALIFORNIA COASTAL WATERS... None.