textproduct: Eureka

KEY MESSAGES

* Above normal temperatures likely through Thursday, including along the coast.

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

SYNOPSIS

Much warmer temperatures are likely today through Thursday, with warm temperatures even at the coast. Breezy offshore wind will bring locally elevated fire danger today and Wednesday. Cooler temperatures return late this week into the weekend.

DISCUSSION

Building high pressure today through Thursday will bring much warmer than normal temperatures, both to the interior and the coast. Today, 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 or slightly above 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 valleys are likely to see overnight lows also trend upwards into the 50s or low 60s. Temperatures this low is providing enough cooling at night to lower the HeatRisk which has also kept conditions below advisory criteria. Still, 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 on Wednesday. Offshore flow weakens Wednesday night into Thursday, which may support more coastal stratus to form or move onshore. Currently, stratus is likely to clear again by the afternoon and relatively light sea breezes will still support a pleasant day in the mid to high 60s.

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 may bring light rain to Del Norte and northern Humboldt Counties on Saturday, but confidence remains low. There is around a 50% chance for any measurable rain for Del Norte and 20% for northern Humboldt. Chances for a tenth of an inch are around 20% in Del Norte County. /JB

AVIATION...(18Z TAFs)

Offshore flow largely kept coastal stratus from forming early this morning and VFR conditions are being observed at all terminals. Offshore flow continues tonight and is likely to prevent widespread stratus formation again, but some patchy ground fog around sunrise may bring periodic and brief LIFR impacts. Any low clouds will lift and scatter shortly after sunrise. /JB

MARINE

Northerly winds have eased and wind-driven seas have started to subside. 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/JJW

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 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. Elevated to locally critical fire weather conditions are possible in the highest elevations of Del Norte, Trinity, and Humboldt Counties tonight into Wednesday morning with these breezy winds. Troughing late this week into the weekend will return cooler temperatures and a deeper marine layer.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 6 AM PDT Wednesday for PZZ470.

Small Craft Advisory until 6 PM PDT this evening for PZZ475.