textproduct: Eureka

SYNOPSIS

Much warmer and drier than normal conditions will build today and through the weekend. Cooler conditions return next week with chance for wetting rain mid week.

KEY MESSAGES

-Chance for frost in northeast Mendocino and northern Lake tonight.

-Interior highs in the low 80s this weekend.

-Slight chance of wetting rain and thunderstorms mid next week.

DISCUSSION

High pressure has started to build over the area, bringing clear skies and dry weather. Temperatures will rebound today with many interior valleys in the 70s. Overnight low temperatures will be slightly warmer than last night's, with generally 30s to low 40s likely for much of the area. Frost potential has waned slightly with this warmup, but some areas in northeastern Mendocino and northern Lake (the Pillsbury Lake Area, Potter Valley, & Covelo) could still see frost tonight with temperatures dipping into the low to mid 30s. A Frost Advisory has been issued for northeast Mendocino and Northern Lake for this frost potential.

The warming trend continues this weekend with 80s likely for many interior valleys. A shallow marine layer on the coast will support coastal temperatures approaching or exceeding 70 in some areas, especially a couple miles inland.

High pressure weakens going into early next week as a trough digs into the Pacific Northwest and a cutoff low approaches the area. Currently, any potential rainfall looks light, with only around a 60% chance of wetting rain (over 0.1") over a 72-hour time span. Chances for over an inch of rain are around 10-20% in the mountains. Timing and magnitude of precipitation will be highly dependent on the position of this cutoff low. Interior thunderstorms may be possible depending on the position of the low, with NBM showing around 10-20% chances Tuesday to Thursday next week. JB

AVIATION...18Z TAFs

VFR conditions prevail with building high pressure and a relatively dry airmass. A slight increase in surface moisture is noted on the sounding for early Saturday morning. Some shallow ground and inland valley fog was observed Friday morning, so there is a slight chance (less than 30%) for isolated stratus or patchy ground fog around Humboldt Bay Saturday morning. Northerly winds will bring some afternoon gusts before easing and turning light offshore overnight.

MARINE

A westerly swell continues to subside while northerly winds strengthen. Some localized gale strength gusts of 34 kts are likely with an expansion fan around and south of Cape Mendocino and in the far norther waters near the Oregon border. The northerly winds will quickly subside Saturday as a strong ridge of high pressure centers over the N CA waters. Seas are forecast to drop below 10 ft late Friday, and the lingering short period seas will quickly fade going into Saturday morning. Winds and seas will be low through the weekend and into next week. The northerlies will begin trending higher Tuesday. Gale strength northerlies will be possible by Wednesday.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory from 1 AM to 9 AM PDT Saturday for CAZ110- 111-114.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 6 AM PDT Saturday for PZZ450-455.

Small Craft Advisory until 11 AM PDT Saturday for PZZ470- 475.