textproduct: Eureka

SYNOPSIS

Dry weather and above normal daytime temperatures will continue through much of the upcoming week. Overnight and morning temperatures will remain chilly with patchy dense fog along the 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 normal temperatures through much of the upcoming week as a resilient high pressure ridge remains over the Western CONUS. Visible satellite imagery depicts sunny to partly cloudy skies across the interior, with high- level clouds streaming southeast this afternoon. Coastal stratus continues to lift and scatter out, bringing a period of sunshine to much of the coastal areas. A shallow marine layer around 2000 feet is expected to redevelop again tonight and into Monday. 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 shows 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 normal through the end of the month and into early February. /ZVS

AVIATION...(18z TAFs)

Despite an encroaching marine layer overnight, the persistent high pressure will improve flight conditions as the day continues. LIFR conditions will linger a bit longer at KACV with some improvements by 00-01z, according to model guidance. KACV has a 40-43% probability of <500ft ceilings by 05z, so a short lived MVFR/VFR period of flight categories. Northerly winds will also have an easterly component at KACV by 05z as well. Northerly winds at KCEC under 7-10kts for the TAF period at their max. Prevailing VFR conditions at KUKI through the evening. /EYS

MARINE

Northerly winds will continue to build tonight with wind waves around 3-5ft and a westerly swell around 4ft at 13 seconds. The strongest winds will develop late tonight around 20kts gusting 25-28kts, south of Cape Mendocino. This will generally bring wind driven waves of 3 to 5 feet. Near shore waters could see areas of 6 foot waves just downwind of Cape Mendocino and likely perpendicular to the Cape with a slight northern proximity. North of Cape Mendocino northerly winds are expected to increase to around 10 kt tonight. These conditions are expected to persist through Monday evening and ease 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/EYS

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 16-17seconds. 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 Monday night through Tuesday evening for CAZ101-103-104.

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

NORTHWEST CALIFORNIA COASTAL WATERS... None.