textproduct: Eureka

KEY MESSAGES

- Northerly breezes near the coastline through the weekend.

- Hotter temperatures over the holiday weekend.

SYNOPSIS

Northerly breezes will persist along the coastline through the weekend into the first half of next week. Temperatures will warm into the weekend with interior valley high temperatures in the mid to high 90s.

DISCUSSION

High pressure is strengthening through the Four Corners region and into Northern California. Temperatures for the interior will warm to the mid to upper 90s, and locally up to 100 through the weekend. This will bring some minor to isolated moderate heat risk through the holiday weekend.

Some moisture from tropical system Douglas off Baja, California will be drawn northward Sunday and perhaps Monday as a trough nudges down from the Pacific Northwest. The elevated moisture available for thunderstorm development still looks to stay mainly east of Trinity County through the Sacramento Valley and mid-level lapse rates are weak. This will still bear watching if higher moisture is forecast, or a farther west extent is modeled. Northeast pacific troughing will then weaken the SW high and lower temperatures some.

Low clouds and fog potential are depicted for portions of the coast on July 4th. There are some indications effective diurnal mixing may delay the stratus onset around Humboldt Bay, but there are strong indications the stratus will indeed form through the night at some point. Along the coast, in general, there is a 20% chance of ceilings falling below 500 feet by sunset while chances of ceilings below 1000 feet is around 40%.

AVIATION

Stratus was much more widespread along the Northwest California coast this morning with ceilings in LIFR at CEC and ACV. Some clearing at the coast is now occurring but this should be short lived at any coastal terminal with stratus redeveloping/expanding through the evening hours. LIFR is likely as the marine layer inversion strengthens in response to the building ridge. Inland, VFR will prevail except for areas where stratus propagates up near coastal valley locations. /RPA

MARINE

Northerly winds along the coast remain strong as a thermal trough strengthens over the interior keeping the pressure gradient tight. Thus, small craft advisories remain in place over the outer waters zones. The gradient will tighten slightly Saturday night into Sunday and gusts to near gale will be possible in the northern outer waters for a 18-24 hour period. Otherwise, a deepening trough off the Pacific Northwest will finally disturb the pressure gradient enough that small crafts may be able to fully end early next week. /RPA

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 PM PDT Sunday for PZZ470-475.