Marine Weather and Tide Forecast for Westhaven-Moonstone, CA

DISCUSSION
An upper level low with a frontal boundary ahead of it is approaching the area Saturday morning. This is expected to move across the area early int he morning bring a round of light rain. Later in the morning and into the afternoon the instability increases some and there is the potential for showers and thunderstorms in the afternoon. This will mainly be north Mendocino county with areas farther south seeing a lower potential for showers and thunderstorms. In Mendocino and Lake counties in the morning there is 300 to 500 j/kg of CAPE on the HRRR, but at the same time there is quite a bit of CIN which is likely why the model Reflectivity shows so few showers. As the boundary moves to the northeast and heating increases through the day. It looks like there is a fairly brief wind in the late morning and afternoon for thunderstorms. In Weaverville the HRRR increase surface CAPE to over 300 j/kg and CIN drops. This may be enough for some thunderstorms to develop. The NAM sounding shows a quick increase of deep cape in the early afternoon for a few hours before it drops back down again.

Saturday night into Sunday morning the showers are expected to diminish, although there will likely still be a few around. Sunday afternoon and evening the shower coverage is expected to increase again and there is the chance for thunderstorms over the interior. This is due to the upper level low moving over the area.
Instability and lapse rates look less favorable for thunderstorms than on Saturday, but they are still possible north of Mendocino county.

Monday high pressure starts to build into the area and showers are expected to come to an end in the morning. Valley fog is likely in many areas due to the recent rain. Dry weather is expected to continue through most of the Tuesday. The next chance for rain is expected Tuesday night and Wednesday. Rainfall amounts are expected to be fairly light, however snow levels are expected to drop to around 5000-6000 feet Wednesday morning. Dry weather is expected to return for Thursday. MKK

AVIATION
(6Z TAFs)...Outside of brief LIFR to IFR impacts due to stratus and/or ground fog, conditions are likely to remain VFR for the next 24 hours. A fast moving cold front approaches Saturday morning increasing the North Coast's chance of showers beginning at 15Z (+/- 2 hrs). A very slight chance of lighting is possible for terminals as well beginning around 18Z (+/- 1 hr). VFR conditions are expected through this frontal passage with a chance (20-40%) of MVFR due to decreases in visibilities.

MARINE
A mid period northwest swell has arrived and has likely peaked at around 8 to 10 ft. A small craft advisory remains in effect for the northern outer waters through 10 AM today for combined seas of over 10 ft. Other areas could briefly see seas over 10 ft as well, but generally this swell will be subsiding through the day Saturday.

A weak cold front moves through the area today, bringing a quick burst of northwesterly winds. Even the high end models are showing gusts peaking at 20 to 25 kts. Some locally gustier winds are possible around the strongest showers, along with an isolated thunderstorm. After this passage, winds will diminish again into Sunday. Winds and seas are likely to remain mild through at least Wednesday of next week before northerlies build in as a fairly weak thermal trof set up looks to form over the waters. JB/DS

COASTAL FLOODING
A nearing full moon phase will bring higher than usual tides over the next several days. The worst case forecast tide levels over Saturday and Sunday are high, possibly reaching as high as 8.3ft, but will remain below advisory and impact level for Humboldt Bay.

EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 10 AM PST Saturday for PZZ470.