textproduct: Eureka

KEY MESSAGES

* Another round of light to locally moderate rain likely Tuesday.

* Warmer temperatures for the end of the week and through the weekend.

* Stronger storms with heavy rain possible starting around November 10th.

SYNOPSIS

Light to moderate rainfall quickly moves through Tuesday. Conditions will then remain mostly dry apart from low chances for additional light rain or showers through the week and weekend for the North Coast. There continues to be indications a stretch of stronger Pacific storms capable of heavy rainfall and strong winds will begin near the 10th.

DISCUSSION

The radar is already showing some light showers drifting toward the coast Monday afternoon. The showers are moving off of an approaching area of low pressure, which will continue generally towards southern Mendocinco. An associated surface low will initially have some stronger southerly winds on approach, but the low will be quickly weakening. Some gusty south winds are still likely, mainly over the ridges Monday night through late Tuesday morning.

Rainfall will generally be light with this feature, particularly north of the King Range where downsloping winds will enhance the drying rain shadow. Of note, there will be instability around the low, bringing a chance for thunderstorms along the Mendocino coast and perhaps into Lake County. This convective activity will bring oportunity for locally high rainfall amounts in the described locations.

Some weak fronts will bring some chances for light rainfall for mainly the Far North Coast through the week and weekend, but chances for over 0.1 inch of rain is only up to 35% for Del Norte county. High pressure will also be building in, allowing for warmer temperatures late week and through the weekend.

Attention remains focused on the extended forecast when models and ensemble clusters are coming into closer agreement on a shift to a more active weather pattern. The threat start after the 9th, likely near of after the 10th. For that period, there is a 40 to 50% chance of exceeding two inches of rain over a two day period, and a 30 to 40% chance of exceeding three inches, respectively. Cluster analysis shows 50% of the members with over 2 inches in a 24 hour period. The possible atmospheric river storm system would be capable of strong southerly winds as well. JJW

AVIATION...18Z UPDATE

Prefrontal conditions are expected through the day today with light, variable winds with a slight south to southeast component. Overcast clouds over 15k ft are present as a weak marine layer exists along the coast. Large breaking waves are increasing the exposure of coastal terminals to hazy, misty conditions down to MVFR status. Tonight, winds will turn more southerly for all areas as a cold front approaches NW CA. Expect weak rainshowers and possible gusty breezes near storms with downbursts possible. Winds near terminals by terrain could be turbulent as well. MVFR is expected through tomorrow morning between 12Z and 18Z. DS

MARINE

An approaching cold front will impact the area over the next 24 hours. Southerly winds increase ahead of the front up to moderate breezes. A narrow area north of Cape Mendocino will likely have localized stronger winds up to fresh breezes. As this front approaches, winds continue to increase overnight into the morning. A brief period of near-gale gusts is possible from around 3AM to 6AM or so for all waters as the frontal boundary passes overhead. A pre- existing long period, NW swell is being recorded with waves of 9- 12ft at 18-20sec. This swell is expected to build through the day. Short period seas will also build as winds increase. This NW swell and the Southerly winds waves will cause a chaotic sea state. A small craft advisory has been issued as a result for the outer waters. Winds weaken slightly after the frontal passage, yet the NW swells are likely to continue through the week. DS

BEACH HAZARDS

A very long period northwest swell is peaking Monday afternoon, but the size and energy will be very slow to subside. This continues to bring an extreme threat for sneaker waves through the evening as winds remain light and other wave groups remain limited. A Beach Hazard Statement is in effect through this evening for this sneaker wave threat.

Sneaker waves are relatively large, unexpected waves with long period between large sets. Up to 30 minutes may pass between waves. Large, unexpected waves can sweep across the beach without warning, sweeping people into the sea from rocks, jetties, and beaches. Avoid jetties, steep beaches, and stay much farther back from the ocean!

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement until 10 PM PST this evening for CAZ101-103-104-109.

Frost Advisory from midnight tonight to 9 AM PST Tuesday for CAZ110-111-114.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 1 AM to 9 PM PST Tuesday for PZZ470.

Small Craft Advisory from 8 PM this evening to 9 PM PST Tuesday for PZZ475.