textproduct: Eureka

SYNOPSIS

Dry weather and above average daytime temperatures will continue through much of this week. Overnight and morning temperatures will remain chilly with patchy dense fog along river valleys and around Humboldt Bay. Chances of precipitation return late in the week or weekend.

DISCUSSION

Quiet weather conditions continue across Northwest California with dry weather and above average temperatures through much of this week as a resilient high pressure ridge remains over the Western CONUS. A shallow marine layer, around 2000 feet, is expected to continue to blanket the coast through late this morning. While daytime warmth continues, expect chilly mornings with patchy dense fog along the river valleys and around Humboldt Bay through much of the upcoming week.

The anomalous 500 mb ridge is expected to weaken by midweek. The pattern shifts late in the work week as the ridge breakdown. Ensemble guidances and cluster analysis show a weak system bringing increasing chances of precipitation late in the week or weekend. There is a 15-45% chances of wetting rain (0.01 inch or more) across the forecast area this weekend, with the highest probabilities along the coastal range in Del Norte and Humboldt counties. The latest WPC/CPC 6-10 day outlook (Jan 23-27) indicate a tilt toward above normal precipitation (33-40% chance). High uncertainty remains regarding the specific details at this moment. A cooling trend is expected as well; however, daytime temperatures are forecast to remain generally above average through the end of the month and into early February. /ZVS

AVIATION

The marine layer remains in place along much of the coast. Around ACV the clouds are firmly in place and it is likely it will remain LIFR early this morning. It may even drop below 1/4 mile at times. KCEC is a bit more patchy with the clouds. It will likely continue to see periods of LIFR conditions, but there may be some breaks in the clouds at times. This morning clouds are expected to lift slightly in the morning and may break out to VFR in the afternoon. However this will likely be shortlived with the HREF showing a quick return of lower cigs and vis in the evening along the coast. Inland areas are expected to see low clouds and fog return to many of the northern valleys, likely in the areas where there was fog on Sunday. UKI is not expected to see much fog, although a few brief periods of it are possible. MKK

MARINE

Northerly winds remain around 10 to 15 kt south of Cape Mendocino with local areas of 20 kt winds south of Cape Mendocino. This will generally bring wind driven waves of 3 to 5 feet. Local areas of 6 foot waves are possible just downwind of Cape Mendocino. North of Cape Mendocino northerly winds remain around 10 to 15 kt. are expected to increase to around 10 kt tonight. These conditions are expected to persist through Monday evening and diminish Monday night.

Monday night and Tuesday the GFS wave model is showing a long period west to northwest wave moving in and building to around 5 to 6 feet at 16 seconds. This is expected to combine with a 3 or 4 foot wave of 12 seconds.

Lighter winds are expected Tuesday and Wednesday before strong to near gale force winds are expected to return late in the week. MKK

BEACH HAZARDS

A moderate risk for sneaker wave will arise during the early Tuesday morning hours. A Beach Hazard Statement, BH.S, has been issued for two separate arrival times of a westerly swell 4- 6ft with a period around 16-17 seconds. The earliest estimated arrival is 12z on Tuesday January 20th for Coastal Del Norte, Northern Humboldt Coast, and Southwestern Humboldt ending around 04- 05z Wednesday. The sneaker wave threat for the Mendocino beach zones will arrive around 15z on Tuesday January 20th, ending around 05-06z. /EYS

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement from late tonight through Tuesday evening for CAZ101-103-104.

Beach Hazards Statement from Tuesday morning through Tuesday evening for CAZ109.

NORTHWEST CALIFORNIA COASTAL WATERS... None.