textproduct: Eureka

SYNOPSIS

Heat peak today with Minor to localized Moderate HeatRisk. There is a chance of isolated mountain showers on Friday. A weak and shallow marine layer will hang along shore. Temperatures will trend lower this weekend weekend. Chances of rainfall returns on Monday as a cold front approaches the forecast area.

DISCUSSION

High clouds continue to stream across the area overnight, while low clouds and patchy fog has developed around the Humboldt Bay and vicinity, and extended along the Eel River Valley. Expect any low clouds and fog to lift and clear out this afternoon.

A broad upper level ridge with above normal 500 mb heights continue to builds into the Pacific Nortwest today, dominating the weathern pattern for Northwest California. Heat peak today across the interior with Minor to localized Moderate HeatRisk as high temperatures climb into mid 90s. The heat will have impacts on anyone without effective cooling and/or adequate hydration. Coastal areas will remain generally in the upper 50s to mid 60s with the breezy northwest winds.

A weak shortwave disturbance will push through from the north late Thursday and Friday. Some ensembles are generating shower activity over east Trinity Friday afternoon. These types of setups usually bare watching for thunderstorm development; however, the mid to lower level environment will be very dry and this will inhibit convective development. There is up to a 10% chance for a thunderstorm over the Yolla Bolly area Friday afternoon. A couple light showers may form otherwise, but no precipitation would likely reach the ground.

High pressure weakens over the weekend, and daytime highs will trend cooler. The combination of light northwesterly flow and a shallow marine layer will present a setup for more persistent coastal stratus with some fog likely through the weekend. Most ensemble members continue to show a trough dipping across the Pacific Northwest early next week. Very light showers to light drizzle will be possible. There is currently 20 to 35% chance for 0.1 (wetting rainfall) over northern Humboldt through Del Norte. This will be dependent of how far south the low tracks, and if it ends up farther north, little to no rainfall will fall through the already dry antecedent environment. / ZVS & JJW

AVIATION...(06Z TAFs)

MVFR ceilings around 1200 feet at KACV, while VFR conditions at KCEC and KUKI with high-level clouds streaming across the area. Well offshore, a shallow marine layer will continue to slowly approach the nearshore through this morning. Nearshore southerly winds should push the low clouds into KCEC overnight and into early morning. Expect MVFR to IFR conditions for the coastal terminals overnight, lowering to LIFR conditions after 12Z. Low clouds and fog/mist are expected to gradually lift and scatter out with the diurnal heating and increasing NW winds, first at CEC after 15Z and after 19Z for KACV.

Short-term model guidance suggests low clouds redeveloping after 22/01Z around Humboldt Bay and vicinity. This should promote MVFR ceiling impacting KACV again. Meanwhile, VFR conditions are expected to prevail at KUKI. Winds will be lighter compared with the last couple of days, but expect NW winds around 10 kts with highest gusts developing during the afternoon, especially at KCEC. /ZVS

MARINE

Northerly winds begin to slowly diminish across the waters as the pressure gradient will shift slightly during the next few days. However, strong to gale-force gusty winds persist across the outer waters through Friday night, with the strongest winds in the northern outer waters. Gale-force gusts are anticipated to redevelop closer to the coast each afternoon in the lee of Pt St George and Cape Mendocino. These winds will continue to generate steep to very steep, hazardous seas across the waters into the weekend.

Northerly winds are expected to diminish this weekend as the high pressure shifts eastward and the pressure gradient relaxes. Seas will also subside this weekend and into early next week, and could be below 5 feet across the waters by Sunday night.

Monday, winds shift to west-northwest as a cold front from the Northeastern Pacific (NEPAC) moves through. Wind shifts to northerly and increase in the wake of the front Monday night through Tuesday. There is a 50-70% chance of gale-force gust winds across the waters on Tuesday, with the highest chances for south of Cape Mendocino. /ZVS

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PDT Friday for PZZ450.

Small Craft Advisory until 10 AM PDT Thursday for PZZ455.

Gale Warning until 11 PM PDT Friday for PZZ470.

Gale Warning until 10 AM PDT Thursday for PZZ475.

Hazardous Seas Warning from 10 AM Thursday to 11 PM PDT Friday for PZZ475.