Marine Weather and Tide Forecast for Ukiah, CA

DISCUSSION
The approach of a deep upper level trough is evident as high level clouds encroach on the CWA The trough axis is currently at the -140W Longitude with a trajectory that will place the vorticity max somewhere south of the SF Bay area. This open wave pattern trough will deepen and form a split flow low by Friday afternoon, with the leading edge bringing southerly winds and instability as cold air advects/overruns the warm air mass. Leaning more towards a positive tilt with this system, there will be less chance of a severe storm outbreak yet localized convection is expected for the interior mountains. PWAT values increase by the weekend to around 0.8 inches.

This afternoon inland areas are expected to see a number of showers and possibly some thunderstorms as well. CAPE varies quite a bit of model to model, but the HRRR mean is showing around 200 j/kg.
Shear is only around 20 kt and mid level lapse rates are generally around 6.5 to 7c/km. This will likely be enough to generate a few thunderstorms this afternoon and well into the evening.

Tonight into Friday, showers are expected to become more widespread as the upper level trough moves in. There is the potential for some thunderstorms again Friday afternoon. Saturday the upper level low starts to move out of the area, but there is expected to be a resurgence of showers in the afternoon with the daytime heating.
High temperatures across the area expected to struggle to break 60 degrees even in the warmer areas. Overnight lows are not expected to drop too much due to the moisture and clouds around. Any areas that do remain clear Saturday night could see some frost.

Sunday clearing skies are expected and temperatures will start to warm back up again. Inland areas are expected to see highs in the 60s. Sunday night into Monday morning is expected to be the coldest night and frost is possible in the colder valleys. High pressure continues to build in through the week with highs around 80 for the inland areas by Wednesday. /MKK /EYS



AVIATION
High level clouds are forecast to cover the CWA as a low pressure system advances. MVFR flight conditions are expected through the TAF period as ceilings drop to around 1500-2000ft. Both KCEC and KACV will probably see light rain tonight. KACV has already received light rain as of 11z as vertically integrated moisture condenses. Coastal stratus is prevalent this morning but confidence is low for this to effect conditions at KUKI.



MARINE
Seas are dropping early this morning but remaining steep waves keep advisory levels into midday Thursday. There is a pronounced and persistent wind eddy for the far northern inner zone and around Point St George starting tonight around 8 pm. The resulting localized southerly flow will generate southerly winds through most of Thursday.

A weak cold frontal system will move into the area Thursday and weaken the pressure gradient. As a result, winds Thursday afternoon will be lighter than yesterday, with even lower winds and seas of 5 ft on Friday. In the wake of the frontal system, northerly winds will begin to increasing Friday night through Saturday. Winds of up to 25 kts are forecast Saturday evening, and can be expected to persist into next week. There is currently a low probability for gale force gusts over 34 kts (25-35%) through that period, and mainly for the afternoons south of Cape Mendocino and Point St.
George.

EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 5 AM PDT early this morning for PZZ450-455.

Small Craft Advisory until 11 AM PDT this morning for PZZ470-475.