textproduct: Eureka

SYNOPSIS

Cool and breezy conditions are expected again today with frost possible again tonight in the colder locations. High pressure is expected to bring warming inland temperatures with highs in the 80s by early next week. More clouds, slightly cooler temperatures and a chance of rain is expected in northern Humboldt and Del Norte counties Friday and Saturday.

DISCUSSION

High pressure is starting to build in, but remains fairly flat with a weather system moving by to the north of the area. There is expected to be some clouds in Del Norte and northern Humboldt counties tonight, although these will mainly be high clouds. Farther south clear skies and a cool airmass will likely allow some frost to form in the more protected valleys of Mendocino and coastal Humboldt counties as well as northern Lake county. So have issued a frost advisory for these areas. This may need to be expanded slightly if temperatures start cooling more quickly than expected. Cold temperatures are also expected in interior Humboldt and Trinity counties, but the official growing season has not started so will not issue any advisories. Wednesday morning is expected to be the coldest morning of the week. Wednesday high temperatures are expected to warm a few degrees over today. Del Norte county may see some high or middle clouds as a shortwave moves by to the north. This may even bring a stray shower or two to Del Norte county. Wednesday afternoon most areas are expected to several degrees warmer than today.

Wednesday night and Thursday a warmer airmass starts to slowly build in. There is the potential for a return of coastal stratus overnight, but confidence is low on this. Frost is looking less likely Thursday morning. Most inland areas are expected to see 5 to 10 degrees of warming over Wednesday. Del Norte county may be the exception if there are clouds lingering. Friday and Saturday a shortwave moving by to the north drags a decaying frontal boundary across northern Humboldt and Del Norte counties. This may cool temperatures a few degrees in these areas or at least slow down the warming. Some rain or drizzle is possible along the northern Humboldt coast and in Del Norte county. Farther south in southern Mendocino county and Lake county the warming trend is expected to continue.

The warming trend is expected to spread across the rest of the Sunday and into early next week. This may expand out of the coast on Sunday and possibly Monday. Offshore flow is expected to weaken starting on Monday and this may keep the coast cooler than expected. Inland areas, especially in interior Mendocino and Lake counties may see some of the warmest temperatures so far this spring. There is a 50 to 60 percent chance of Ukiah and an 80 percent chance of Clearlake exceeding 85 degrees on Monday. Monday is expected to be the hottest day in the next week, although Tuesday could be just about as hot in Lake county. MKK

AVIATION

Gusty N-NW winds expected til 03z, otherwise VFR conditions expected through the TAF cycle. Shallow turbulence over the coastal mountains, specifically 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 and a hazardous seas warning has been hoisted for PZZ455 for later tonight. Wind and seas will drop below criteria for warnings on Wed but winds and seas will remains sufficiently elevated to warrant advisories for small craft 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.

Gale Warning until 9 PM PDT this evening for PZZ455.

Hazardous Seas Warning from 9 PM this evening to 3 AM PDT Wednesday for PZZ455.

Gale Warning until 3 AM PDT Wednesday for PZZ475.