Marine Weather and Tide Forecast for Mendocino, CA

DISCUSSION
Mostly clear skies will continue overnight after a warm, breezy day. Northerly wind gusts along coastal headlands will gradually diminish overnight, turning northeasterly and keeping the marine stratus layer at bay along the northern Humboldt and Del Norte Coasts. Low stratus ceilings are more likely to develop around Humboldt Bay and the Eel River Valley overnight.

Wednesday still appears to be warmest day of the weak as high pressure continues to build ahead of an approaching upper shortwave.
Warm and dry conditions with highs in the mid to upper 80's are expected across the interior while the coast is slightly dampened by marine stratus. Hottest temperatures will be in the mid 80's in UKI and Covelo. RH values will dip into the 20-30% range east of the Coast Ranges. Breezy conditions with 10 to 20 mph gusts possible in UKI Wednesday afternoon will enhance fire weather conditions, but do not meet Red Flag criteria, especially with current status of fuels.

Cloud cover will increase Wednesday night into Thursday an upper shortwave and weak surface low clips northern California. NBM still only holding 10 to 20% chance of rainfall in far northern Del Norte County, mostly north of the Oregon border. The forcing of this system may be enough to allow drizzle to develop within the marine stratus layer. Thursday and Friday broad/weak troughing will drift by to our north, but will not have much more effect than mid level cloud cover and cooler temperatures, especially in interior valleys.
High amplitude ridging expected to return Saturday and Sunday, allowing temperatures to briefly rebound into the 70's and 80's - minor heat risk is possible. Long range model clusters becoming more confident in lowering upper heights overnight into Monday, although rainfall potential is still very uncertain.

AVIATION
Overall wind speeds/gusts will decrease with time overnight, with a secondary peak occurring close to 22Z Wednesday along the coast. Even at UKI wind gusts in the afternoon are forecast by the NBM mean at 18 KTS from 300 degrees. The greatest chance of LIFR ceilings along the coast at CEC will be between 11Z and 15Z with a 30% chance of LIFR ceilings. Lower than VFR ceilings are even more favored after 00Z Wednesday (except for LIFR) with a 50% chance of ceilings below 2K feet between 03Z and 06Z Wednesday at CEC (40% at ACV). NBM advertises a 20% chance of light precipitation Wednesday afternoon/evening. Wind gusts up to 20KTS from around 300 degrees are still within the first standard deviation from the NBM at CEC near 22Z. There is also about a 30% chance of MVFR visibility along coastal terminals 12-17Z Wednesday, but not strong enough of a signal to throw into the forecast for now. /MH

MARINE
Hi-res models predict north wind gusts to 34-36KTS overnight for over half of the area of the southern outer waters, with the typical fan of stronger winds south of Cape Mendocino, thus the gale warning will persist into Wednesday morning, with a small craft advisory likely to follow up on Wednesday with continued steep waves. Coverage appears minimal to support a gale warning for the northern waters at this time. Steep northerly waves of 6 to 8 ft in the northern waters and 9 to 11 feet in the southern waters on top of a NW swell around 7 to 9 ft will yield combined wave heights of 9 to 11 ft in the northern waters and 11 to 14 ft in the southern waters tonight through Wed AM. Small craft advisories are in effect and inexperienced mariners should avoid going out in these wave conditions. Seas are forecast to remain higher and steep on Wednesday due to this same wave combination, though northerly winds should be less than yesterday. Wind and waves are forecast to ease toward the end of the week and perhaps into the weekend. It will not take much of a gradient for wind gusts to reach 25-30 kt and for steep wind waves to reach 6 ft for the southern waters and advisories for small craft may still be warranted. A couple of long period swell groups arrive over the weekend; one from the SW and another from the WNW. These swell groups do not appear all that energetic to pose a moderate or extreme risk for sneaker waves at least in our waters over the weekend. It will need to be monitored for possible beach hazards for S and SW faces shores. Otherwise, quieter and fairly tranquil marine conditions are expected over the holiday weekend. DB/MH



EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 9 AM PDT Wednesday for PZZ450.

Small Craft Advisory until 3 AM PDT Thursday for PZZ455.

Small Craft Advisory until 9 PM PDT Wednesday for PZZ470.

Gale Warning until 9 AM PDT Wednesday for PZZ475.