textproduct: Eureka

KEY MESSAGES

- Temperatures will warm quickly with minor to moderate HeatRisk expected Thursday through the weekend

- Elevated fire weather conditions in Lake County with low afternoon relative humidity and gusty winds Wednesday through Thursday.

- Breezy winds are expected along the coast Wednesday and Thursday afternoons.

SYNOPSIS

Clearing skies and temperatures below seasonal normals are expected Tuesday. Temperatures are expected to warm to the upper 90s to around 100 late week into the weekend with a moderate heat risk. Breezy winds are expected Thursday and Friday afternoon.

DISCUSSION

Clouds across the area have been slowly clearing out as high pressure builds in. Today is expected to be the coolest day for quite some time across the interior. Breezy north winds have developed along the coast this afternoon. Tonight mostly clear skies are expected, although there may be some clouds in the river valleys near the coast. Tonight will be the coolest night for some time as well with lows in the low 40s in the cooler interior valleys. It is possible some of the coldest spots such as Hayfork will see temperatures briefly hit 35 or 36 and some frost could form. Northeast winds over the higher terrain is expected to help keep the coastal areas clear tonight. Wednesday temperatures are expected to start warming in earnest. Most inland areas are expected to see highs well into the 80s with the warmer locations around 90. As high pressure continues to build in the higher terrain will see the dry air start to filter in. This is expected across the area, although the lowest RH is expected in eastern Lake county. Breezy north to northeast winds are expected Wednesday night into Thursday morning and this will elevate fire danger early Thursday morning. See fire weather section for details. Thursday afternoon high temperatures in the warmer valleys are expected to be around 100. This is expected reach areas fairly close to the coast such as Gasquet, Garberville and Boonville with these areas potentially seeing highs in the mid to upper 90s. The heat risk is moderate across the interior areas of Mendocino and Lake counties starting on Thursday and lasting several days. So have decided to issue a heat advisory starting Thursday afternoon. This may need to be expanded as it gets closer.

Friday and into the weekend high pressure is expected to remain strong over the area. The big question is when the marine layer will start to influence the near coastal areas. The current forecast has the influence starting on Friday in the areas fairly close to the coast and expanding the slightly cooler temperatures over the weekend. There is low confidence on how how quickly this marine influence will move inland. Friday the heat risk remains moderate in eastern Mendocino and Lake counties and also expands into eastern Trinity county. So a heat advisory may be needed in portions of Trinity county starting on Friday, but will hold off on that for now. For now have the heat advisory ending on Friday in portions of Mendocino and Lake counties, but this may need to be continued into Saturday. Some gradual cooling is possible Sunday morning, but this may be limited to the near coastal areas such as Ukiah, Garberville and Gasquet. MKK

AVIATION

VFR conditions are in place across much of the area with some MVFR conditions in the Humboldt and Del norte interior areas. Skies are expected to be generally clear tonight with some offshore flow. However there is the potential for some of these clouds over the hills to linger and these may impact KACV later tonight. KCEC is expected to have more offshore flow and this should limit the potential for clouds. Any lingering clouds Wednesday are expected to clear fairly quickly with breezy coastal winds. Northwest winds are expected with gusts to 20 to 30 kt in the afternoon. MKK

MARINE

High pressure is building in and northerly winds are increasing across the area. These have slightly slower than expected to increase near the coast. Meanwhile the northwest swell continues around 7 feet at 10 seconds. This is also combining with a 22 second southerly swell that is around 3 feet. These winds are expected to increase tonight through Wednesday night. Gales look on track to start in the southern outer waters by midday and gradually expand closer to the coast farther north through Wednesday evening. At this point gales are expected to make it into the northern inner waters so have a small craft advisory to highlight the near gale force gusts. By this point the waves will be dominated by short period wind driven seas. The only other wave that may be noticeable would be some southerly waves on protected south facing beaches from the long period wave energy.

These near gale or gales are expected to continue through the day Thursday. They may diminish some overnight near the coast, but are expected to increase again in the afternoon. Friday the models are starting to show the winds push farther off the coast in the southern waters. Confidence is low on this and it is possible the gales will need to be extended.

FIRE WEATHER

High pressure is build into the area and bringing warmer and drier conditions. Nearly 10 degrees of warming is expected on Wednesday over today with nearly that again on Thursday. Along with this very dry air is expected to move in and this will lower RH each day. The ridges are expected to see poor RH recoveries by Thursday morning. This will combine with some northerly winds over many of the higher ridges. The strongest winds are expected to be in the Yolla Bolla's and down into the higher terrain of eastern and southern Lake county. This will increase the fire danger so have issued a red flag warning for Thursday morning. Fuels are likely still marginal, but winds of 15 to 30 mph and RH is only expected to increase to 20 to 40 percent. This is solidly into the red flag warning criteria. Thursday afternoon RH is expected to drop into the low teens in much of the interior valleys, but the winds are expected to diminish by the afternoon so have ended the Red flag warning in the morning. This may need to be extended if the winds are expected to remain elevated longer.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory from noon Thursday to 10 PM PDT Friday for CAZ113-114-118>120.

Red Flag Warning from 11 PM Wednesday to 9 AM PDT Thursday for CAZ419-420.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 2 PM Wednesday to noon PDT Thursday for PZZ450.

Small Craft Advisory until 2 PM PDT Wednesday for PZZ455.

Gale Warning from 2 PM Wednesday to 3 AM PDT Thursday for PZZ455.

Small Craft Advisory from 7 AM to 9 PM PDT Wednesday for PZZ470.

Gale Warning from 9 PM Wednesday to noon PDT Thursday for PZZ470.

Small Craft Advisory until 10 AM PDT Wednesday for PZZ475.

Gale Warning from 10 AM Wednesday to noon PDT Thursday for PZZ475.