textproduct: Eureka

KEY MESSAGES

* Moderate sneaker wave risk continues today south of Cape Mendocino.

* Much above normal temperatures likely Tuesday through Thursday, including along the coast.

* Locally elevated fire danger for the higher elevations Tuesday and Wednesday.

SYNOPSIS

The moderate risk of sneaker waves continue south of Cape Mendocino through this evening. Much warmer temperatures are likely Tuesday through Thursday, with warm temperatures even at the coast. Cooler temperatures return late this week into the weekend.

DISCUSSION

Generally mild, near normal conditions are likely today as high pressure begins to rebuild over the area. Interior high temperatures are forecast to be in the high 80s to low 90s. Coastal stratus eroded late this morning bringing sunny conditions even to the coast. Coastal areas are likely to see high temperatures in the mid to high 60s.

Tonight, light offshore flow may keep coastal stratus from reforming. The highest chances will be around Humboldt Bay, but this will likely not be widespread and perhaps only for a few hours. Offshore flow will bring warmer low temperatures as high pressure and warmer air aloft continue to build, with even the coldest interior valleys in the 40s or low 50s.

Building high pressure Tuesday through Thursday will bring much warmer than normal temperatures, both to the interior and the coast. On Tuesday, temperatures are forecast to be in the high 80s to the mid 90s for most interior valleys, while the immediate coast could break 70. Wednesday and Thursday, the ridge strengthens, bringing near triple digit temperatures to most of the interior valleys. This includes valleys close to the coast which may not have experienced temperatures this high so far this year, including Garberville and the Eel River valley. Interior areas will see widespread Moderate HeatRisk which corresponds to a moderate risk for heat-releated illness to those without proper cooling. Drink plenty of water and stay safe out there! Coastal areas also continue to warm as offshore flow continues to inhibit coastal stratus formation with 70s possible at the immediate coast and 80s possible just a few miles inland.

Subtropical moisture from the remnants of Hurricane Marie arriving Wednesday will complicate the forecast somewhat. Instability continues to be modeled near zero with a less than 5% chance for MUCAPE over 100 J/kg. Still, cloud cover could bring slightly lower high temperatures than currently expected Wednesday, along with a few virga showers.

Troughing rebuilds late this week into the weekend, returning near normal temperatures and coastal stratus by Friday. By this weekend, much of the interior is forecast to be in the 70s and 80s with the coast in the low 60s. A weak front moving north of the area may bring a few light rain showers to Del Norte County this weekend, but chances remain low (around 20%). /JB

AVIATION...(18Z TAFs)

Stratus has cleared along the coast and only a few high clouds are being observed across NW California. Offshore winds developing overnight is expected to limit stratus reformation tonight. Still, HREF is showing around 20% chances for IFR to LIFR stratus to form around Humboldt Bay which may affect ACV. Any stratus will likely lift and scatter shortly after sunrise on Tuesday. Otherwise, VFR conditions are expected for the next 24 hours. /JB

MARINE

Northerly winds build today and peak this evening. Near-gale force gusts are possible in the lee of Cape Blanco and Cape Mendocino late this afternoon and this evening. Steep seas of 6 to 10 ft are possible with these winds and may propagate into the nearshore waters. Both winds and seas ease Tuesday as the pressure gradient weakens. Breezy northerly winds return Thursday and are likely to continue south of Cape Mendocino through the weekend. Along with wind driven seas, a long period south swell from Hurricane Marie at around 3 to 5 ft will persist through the week. /JB

FIRE WEATHER

Much warmer and drier conditions are expected as high pressure rebuilds this week. High temperatures in the interior valleys will climb in the high 90s to just over 100 Tuesday through Thursday. Afternoon relative humidities will fall into the teens or single digits in the eastern portions of the area. Offshore flow developing overnight will result in poor overnight recoveries for the higher elevations and winds may be locally breezy. Near-critical to locally critical fire weather conditions are possible in the highest elevations of Del Norte, Trinity, and Humboldt Counties Tuesday night and early Wednesday morning with these breezy winds. Troughing late this week into the weekend will return cooler temperatures and a deeper marine layer.

BEACH HAZARDS

A long period southerly continues in waters, only slowly losing energy through the week, but 15 to 16 second periods are still being recorded. Thus, there is an ongoing risk of sneaker waves today for south facing beaches in Mendocino and Southern Humboldt counties, including the Lost Coast Trail.

Sneaker waves are a unique hazard, with up to 30 minutes between waves. Large, unexpected waves can sweep across the beach without warning, sweeping people into the sea from rocks, jetties, and beaches. These sneaker waves can also move large objects such as logs, crushing anyone caught underneath. Even ankle to knee deep water can knock you down and drag you out when a sneaker wave hits. Pay attention and stay above the high water line and any wet sand to stay safe. If the ground is wet, waves have surged there recently. Stay safe and never turn your back on the ocean!

EKA WATCHES/WARNINGS/ADVISORIES

CA... Beach Hazards Statement until 11 PM PDT this evening for CAZ104-109.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 6 AM PDT Tuesday for PZZ455.

Small Craft Advisory until midnight PDT Tuesday night for PZZ470.

Small Craft Advisory until 6 PM PDT Tuesday for PZZ475.