textproduct: Eureka

KEY MESSAGES

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

* Locally elevated fire danger for the higher elevations Wednesday.

*Chances for light rainfall for Del Norte or northern Humboldt Saturday.

*Locally elevated fire danger Thursday and through the weekend for southern areas that stay drier.

SYNOPSIS

Much warmer temperatures are likely today through Thursday, with warm temperatures even at the coast. Breezy offshore wind will bring locally elevated fire Wednesday. Cooler temperatures return late this week into the weekend, with some chances for light rain for the northern end of the area.

DISCUSSION

Building high pressure through Thursday will bring much warmer than normal temperatures, both to the interior and the coast. 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- related 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 for the far southern zones, 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...(6Z TAFs)

Drying from increasing offshore flow will continue to maintain VFR conditions. There may be a few instances of ground fog early Wednesday morning, but chances for this are only 10-20%. Surface winds will be light while the interior higher elevations see gusty easterly winds through 15Z Wednesday. Chances for coastal stratus begin to increase again later after 2Z Thursday.

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, there will be some small long period southerly swells up to three feet will exist in the water Thursday and through the weekend. Winds and seas will lower again late Friday and into the weekend with a passing trough.

FIRE WEATHER

Much warmer and drier conditions arrived as high pressure strengthens. 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. Afternoon westerly to northwesterly winds will increase late in the week, and into the weekend, particularly on Saturday. The largest areas of concern through that period will be areas south, such as Lake County, that will remain dry.

EKA WATCHES/WARNINGS/ADVISORIES

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