Marine Weather and Tide Forecast for Philo, CA

DISCUSSION
Latest satellite imagery depicts a fast moving upper- level shortwave trough moving into the Pacific Northwest and clipping the northern portion of the area. An associated decaying front is bringing light rain to Del Norte and portions of Humboldt this afternoon. Trinity County and portions of Mendocino are only expected to see a few sprinkles with Lake county likely staying dry or seeing a few sprinkles in the northern mountains.
The aforementioned cold front will exit the area late in the afternoon/early evening. Any rain is expected to tapper off this evening. Northwest onshore flow is expected to keep significant low level moisture in the valleys and along the coast. Fog may also develop in the northern valleys.

High pressure is expected to build into the West Coast downstream in the wake of the upper-level trough on Sunday. This will allowed dry east-northeasterly winds developing across the area.
Gusty easterly winds are expected to develop over the higher terrain across the interior Sunday evening into Monday morning.
Gusts from 25 to 40 mph are possible over the higher terrain, with the strongest winds over the eastern portion of Lake County.
These winds are expected to diminish throughout the day on Monday, with another round of gusty offshore winds over the higher terrain Monday night into Tuesday, although not as strong as Sunday night-Monday.

Cold, dry air advection over the next couple days alongside generally offshore winds will promote mostly clear skies and cool temperatures Sunday into Monday. As a result, a strong radiational cooling will become probable across interior portions of NWRN CA, with fog development across those shelter valleys Sunday night. Offshore flow also keeps the air at the coast dry.
Gradually warming temperatures are expected on Monday. Tuesday increasing clouds may keep temperatures slightly cooler.

Wednesday, ensemble cluster indicates the high pressure will begin to weaken and shift eastward, with an upstream upper level trough and embedded cutoff trough approaching the area. There is a lot of uncertainty about the evolution of this system across the area.
Now, all ensemble and deterministic models are trending drier on Wednesday and Thursday. Clusters are indicating there is just a 35% chance of precipitation on Thursday across the area, and 25% chance for Friday.

Next weekend, the ensemble models are showing the potential for moderate to heavy rain with the ensembles showing increased probabilities of higher IVT. The NBM is showing the 75th percentile (higher end) of 1.5 to 4 inches for a 24 hour period ending 4pm Saturday. The 25th percentile (lower end) range from few hundreths to 1 inch for the same time frame. This time frame will need to be watched as it gets closer. -ZVS



AVIATION
A weak front has moved through the area early this afternoon, bringing light rain and deteriorating conditions to the terminals. Conditions are expected to swing between VFR/MVFR and IFR/LIFR as rain bands come on shore. The front will move out of the area this evening, and conditions will improve to VFR with mostly clear skies into tomorrow. Mendocino and Lake counties are not expected to see participation, so UKI is forecast to remain VFR for the next 24 hours. Some patchy fog is possible at all terminals early Sunday morning, but confidence on there being significant impacts is low. JB



MARINE
Northerlies are expected to pick up this evening as a front moves out of the area. Winds are forecast to peak Sunday afternoon with gusts of 25-30 kts possible nearshore and gales possible in the lee of Cape Mendocino. Steep wind waves will be associated with these winds. At the same time, a large mid-period westerly swell will build in, increasing significant wave heights to 14 to 15 ft. Conditions will improve early next week. JB



BEACH HAZARDS
A long period westerly swell is forecast to fill in Tuesday, peaking around 8 ft at 16 seconds. This will result in a moderate risk of sneaker waves Tuesday into early Wednesday. Be cautious visiting beaches and jetties Tuesday, as relatively large and unexpected waves could sweep in without warning. Stay much farther back from the water and never turn your back on the ocean.
JB



EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory from 9 PM this evening to 3 PM PST Monday for PZZ450-455-470.

Small Craft Advisory from 9 PM this evening to 3 AM PST Sunday for PZZ475.

Gale Warning from 3 AM to 9 PM PST Sunday for PZZ475.