textproduct: Eureka

SYNOPSIS

Warmer and drier conditions continue Monday before another weak cold front with light rain crosses the area around Tuesday. COnditions will then remain mild and mostly dry through the end of the week.

DISCUSSION

Drier air will quickly built across the area today with clear skies allowing interior locations to sea highs near 70. Clear skies and dry air overnight will likely bring a return to frost at least for some interior locations, though dewpoints at the coast remain to high for widespread frost closer to shore. High pressure briefly building into Monday will allow some interior highs to return near 70 for at least one more afternoon.

There is high confidence that a modest cutoff low and cold front will quickly cross the area around early Tuesday. This low shows uncertainty regarding rainfall. Potential is generally higher than the last system but remains low in absolute terms. Most likely rainfall is currently 0.05 to 0.15 inches pretty evenly spread across the area. NBM shows only a 15% chance of any location over 0.25 inches and a 40% chance of little more than drizzle. Moderate south wind is expected along this front with some gusts near 25 mph most likely.

Behind this system, there is much greater forecast uncertainty beyond Tuesday. Most (70%) of ensemble members show weak high pressure through the end of the week with seasonably cool and mostly dry conditions. Temperatures will gradually increase with peak temperatures around Saturday. Similarly, a marine layer near shore becomes more likely as the week goes on. Any potential of rain for the week beyond just coastal drizzle after Tuesday has now evaporated. Long range models suggest the next chance for heavier rainfall is around November 10th with a 50% chance of rainfall over 1.0 inch in that period. /JHW

AVIATION

Dry and unstable air moving in behind a cold front has enabled clear, VFR conditions all day today. Mostly VFR conditions will continue overnight, though a minority of models (20%) show some isolated ceilings near shore of 1 kft early Monday morning. Otherwise, ceilings around 10 kft will gradually build in Monday but otherwise remain VFR.

MARINE

Some moderate winds have built in the southern waters today, but only isolated gusts have reached reach 20 kts with short period seas up to 6 feet. Nearly calm winds return by Monday. A modest cold front is expected to pass early Tuesday with some moderate south winds ahead of the front switching northerly behind the front mid week. With little short period seas in the short term, the sea state will be controlled by a series of swells. Most notably a mild 3 foot, mid period swell from the southwest through mid week. Of larger note, a long period swell will build Monday up to 7 feet at 18 seconds, bringing a risk of sneaker waves near shore. /JHW

BEACH HAZARDS

A very long period northwest swell will begin to arrive this evening and peak near 7 feet Monday. This will bring an extreme threat for sneaker waves as winds remain light and other wave groups remain limited. This swell starts at around 2 ft at 21 secs and builds to around 6 ft at 17 secs by Monday morning. A Beach Hazard Statement has been issued 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 from 6 PM PST this evening through Monday evening for CAZ101-103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 PM PST this evening for PZZ455- 475.