textproduct: Eureka

SYNOPSIS

After a chilly Wednesday morning, temperatures will strongly rebound to begin an extended period of warmer temperatures. Northern Humboldt and Del Norte counties will occasionally see chances for light showers and mainly light drizzle from clipping weather systems. More significant warming is likely late this weekend and next week.

DISCUSSION

Lightening winds and clearing skies allowed for cool to cold temperatures and the formation of frost, including over areas where the official growing season has begun. Frost advisories have been issued over portions of coastal and interior Humboldt and Mendocino counties where the growing season has begun.

Wednesday morning is the coldest of the extended forecast. A weak weather system will clip the area Wednesday through Thursday, increasing cloudcover and brining chances for a few light showers over Del Norte and light coastal drizzle through the Humboldt coast.

A dominant ridge of high pressure will also be building over the west through the week. Another weak, clipping front will temporarily weaken the ridge and will bring more chances for light rainfall or drizzle late Friday and Saturday. Chances for only 0.1 inch or more of rainfall are a little higher for this system from Northern Humboldt and mostly Del Norte (50-75%), but only trace amounts may be recorded for most.

There is high confidence the ridge will begin to greatly amplify through the end of the weekend and next week. Some Minor to locally Moderate HeatRisk conditions are even possible early next week over the interior, mainly south through Mendocino and Lake counties. NBM chances for maximum high temperatures increase to moderate to high (60 to 90%) Sunday for these southern zones. Probabilities are higher early to mid next week. Chances for high temps over 85 are highest Monday, particularly over Lake County (85%).

AVIATION

VFR conditions expected through the TAF cycle. Shallow turbulence over the coastal mountains, specifically for SW Humboldt, remains possible til 08z. Otherwise, lighter winds are expected to prevail into Wed. Chance for coastal stratus with ceilings < 1000 feet AGL increases to 60% Wed night. Lower chances (20%) for IFR vsby n mist/fog by early Thu at coastal terminals (KACV and KCEC).

MARINE

Lingering gale gusts and large steep waves are forecast in the southern waters through this evening as a frontal systems departs to the southeast. Steep waves may continue past the end of the gale warning for the outer waters and a hazardous seas warning has been hoisted for PZZ455 through this morning. Wind and seas will drop below criteria for warnings on Wed but winds and seas will remains sufficiently elevated to warrant advisories for small crafts for PZZ455 and PZZ475. North winds are expected to diminish tonight and Wed for the northern water and remain below advisory level through Fri. Northerly winds increase throughout on Saturday as a frontal boundary lifts out to the NE and high pressure builds to the NW. A short to mid period NW swell around 7 to 9 tonight and Wed is forecast to slowly decay Thu and Fri. Long period SW swell is forecast to build to 2 ft Thu and Fri.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Frost Advisory from 3 AM to 9 AM PDT Wednesday for CAZ103- 109>111-114.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PDT Wednesday for PZZ450- 470.

Hazardous Seas Warning until 3 AM PDT Wednesday for PZZ455.

Small Craft Advisory from 3 AM to 11 AM PDT Wednesday for PZZ455-475.

Gale Warning until 3 AM PDT Wednesday for PZZ475.