Marine Weather and Tide Forecast for Ukiah, CA

DISCUSSION
A weak cold front is visible on satellite offshore far northern California early this morning, and will move onshore late morning or early afternoon. Some drizzle or light rain showers are possible ahead of the front along the coast, particularly north of Cape Mendocino. Some increased precipitation chances also exist in the Trinity Horn in the afternoon, but chances remain less than 15%. Instability is also meager and thunderstorms are very unlikely (less than 5%).

Weak ridging will begin building in behind the trough. Inland valley temperatures are likely to warm into the low to mid 90s, with some upper 90s in Lake County on Wednesday. Temperatures will trend lower next Thursday as another weak shortwave trough passes to the north.
Initial analysis of this trough does not show much chance for convective impacts, but features as this always bear watching this time of year. The main impact appears to be stronger northerly winds behind the front, particularly in Trinity, Mendocino, and Lake Counties. NBM probabilities for gusts over 35 mph Friday are around 40-60%. Ridgetops are likely to have higher gusts. This could be a fire weather concern if it pans out, as afternoon relative humidities remain dry in the eastern portions of our area.

A seasonally anomalously strong trough is then forecast to dive south into the region next Friday. There is currently a low chance for some light showers with a cold upper low and front. There is the potential some of this precipitation may be in the form of thunderstorms with steep lapse rates and elevated instability. One of the more "extreme" scenarios (20% chance) is over a half inch of rain in Del Norte and perhaps a few snowflakes over the highest peaks. Chillier low temperatures are possible behind the system as well, with lows in the 30s likely in most of Trinity and the coldest valleys of Mendocino and Humboldt. JB/JJW



AVIATION
16/06Z TAFs...Ceilings have already come down to 1500ft as of 4z at KCEC. Ceilings could come down even more with NBM suggesting ceilings below 2000ft near 80% probability. Flight categories could degrade to IFR by 11z and lift by the daylight hours. KACV will have similar fate as ceilings are due to drop sooner. Expect IFR at KACV with periods of LIFR in the early morning hours. Gusty northerlies are likely at KUKI by Monday afternoon, lasting into the evening hours with VFR prevailing. /EYS



MARINE
Winds are forecasts to ease from the northern outer waters, reducing small craft advisories to inner and outer waters south of Cape Mendocino. The sea state will be largely dominated by steep short period wind waves. Winds are forecast to gradually decrease and retreat to the southern waters early in the week. As the winds die down, a small mid-period NW swell enters the area waters early Tuesday morning.



FIRE WEATHER
An additional shortwave moving through the area today will bring a low chance for showers in NE Trinity county. The thunderstorm setup does not look great in Trinity, as instability remains meager, but probabilities hover around 5%.

Northerly winds are forecast to increase today, with the strongest winds in southern Mendocino and Lake Counties. These mainly diurnally driven afternoon winds will trend slightly lower Tuesday, but will increase again late next week behind a stronger trough and front. Minimum RH values will trend lower early to mid next week, with some values in the mid to upper teens Wednesday. Locally elevated to some brief critical fire weather conditions will develop with these afternoon wind pulses and lowering RH. JJW/JB



EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 10 PM PDT this evening for PZZ455-475.