textproduct: Eureka

SYNOPSIS

Dry weather and above normal daytime temperatures will continue through Tuesday. Overnight and early morning temperatures will remain chilly with patchy dense fog along the river valleys and around Humboldt Bay. Rain chances start to increase for Wednesday this coming week.

DISCUSSION

Offshore, easterly winds, especially in Lake County are currently showing gusts from 25 to 40 mph over the exposed ridges. Winds are expected to diminish throughout the day into Sunday as the surface pressure gradient decreases. Satellite imagery depicts minimal cloud coverage, except for a surge of coastal stratus in southern Mendocino County. Cold, dry air advection alongside generally gentle to moderate offshore winds will continue to promote clear skies and cool temperatures and tonight into Sunday. As a result, strong radiational cooling will become probable across interior portions of NW CA, with some patchy fog development across the river valleys once again tonight. Freezing temperatures are forecast for the interior valleys with lows in the mid 20s to low 30s. Temperatures for the coast look to be in the mid 30s with a small chance (<15%) of freezing temperatures for some coastal valleys tonight.

High pressure is expected to slowly weaken and flatten Sunday into Monday as a weak shortwave trough moves north of the area, bringing and increasing cloudiness. The 500 mb ridge appears to slowly build back early next week, with conditions slightly warming up. Ensembles and WPC Cluster Analysis continue to suggest a pattern shift as this seemingly never-ending ridge finally breaks down and an upper level trough digs southward across the Pacific, approaching the area by mid week. At this time, there is a 30-50% chance of wetting rain by Wednesday. There are no major impacts expected with this weather system; if precipitation does occur, it would be more beneficial than impactful, especially after the recent dry spell. /ZVS/DES

AVIATION...18Z TAFs

VFR conditions firmly took hold after some lingering inland valley fog cleared out. Surface winds will be light and turning easterly overnight. The drying offshore flow will maintain VFR conditions through this 18Z period. Areas of fog may push northward up the Russian River valley through Santa Rosa overnight. This will have to be watched regarding fog chances at UKI. The much drier airmass is currently expected to limit this threat. Lingering surges Surges easterly to northeasterly winds of 30-40 kts aloft through 2000 ft AGL will bring a risk for turbulence and low level wind shear in Lake County through 9Z Sunday.

MARINE

Northerly winds and seas have peaked and are trending lower. Steep seas will continue to lower through Sunday when combined seas are likely to fall below 5 ft by Sunday as winds remain light. A series of small, mid to long period west swells fill in through Wednesday, each peaking at around 5 ft. Winds turn southerly and start to increase early Monday. NBM currently shows about a 50% chance for gale force gusts in the outer waters by Tuesday. A large westerly swell looks to then build in Wednesday night and Thursday. JJW

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None.