textproduct: Eureka

KEY MESSAGES

* Very dry conditions with gusty northeast winds focused in Lake County will increase fire danger Thursday and Friday.

* A warming trend peaking Today and Friday with interior highs in the 90s.

* Cold front most likely to cross the area Monday into Tuesday. 50% chance of wetting rain along the North Coast.

SYNOPSIS

A general warming trend will peak today and Friday, even for the coast where marine influence remains weak. Cooler and more moist conditions build by the weekend. Early next week

DISCUSSION

High pressure remains over the area this afternoon bringing warm temperatures that are ten to fifteen degrees above normal. An upper level trough continues to drop south through the Great Basin and towards the southern CA coast. This is expected to bring another round of northeast winds to Lake and Mendocino counties tonight and into Friday morning. These winds are expected to continue to bring drier air to the higher elevations. This offshore flow is expected to keep the marine clouds and fog mostly out of the area, although a few local areas of fog are possible. Hot weather is expected to continue in the inland areas on Friday although the coast will be cooler than today.

For the weekend flow aloft becomes more zonal as a weather system moves by to the north of the area. This will drop inland temperatures each day and the marine clouds are expected to expand. Sunday high temperatures may struggle to reach 80 in the warmer valleys with cooler temperatures close to the coast.

The potential for rain has now pushed back until Monday afternoon or Monday night. There is a 30 to 50 percent chance of a wetting rain in Humbodlt and Del Norte counties by Tuesday morning. Farther south probabilities are lower, but there is still the potential for some rain. Some of the models show an upper level low bringing more rain farther south.

As the previous system moves out of the area high pressure starts to build back into the area bringing a return of dry weather and how warm it will be.

AVIATION...18Z UPDATE

Widespread VFR is expected through the day again. Light winds along the coast will lead to decreased chances of any LLT. Late tonight, some of the higher resolution models are suggesting a rebuild of the marine layer, yet confidence is low (~25- 30 %) leading to only a TEMPO group of LIFR for CEC and SCT coverage at ACV for the time being.

Ongoing breezy winds inland will continue through midday before calming this afternoon. N-NE winds will be the dominate direction, yet the terrain's influence could cause some shifts in direction through the day, especially in more complex areas. Winds are forecasted to calm again tonight in the valleys with breezes up to 15mph continuing near the ridgelines, especially in eastern Lake and Mendocino counties. DS

MARINE

Light winds are expected to continue tonight through Friday morning. The waves will remain dominated by a northwest swell and a more southerly swell. The northwest swell is around 5 feet at 12 seconds while the south to southwest swell is around 3 feet at 15 seconds.

Friday afternoon northwesterly winds are expected to start building into the waters. These are expected to first increase in the southern waters and then expand north Friday night and Saturday. These are expected to be fairly shortlived and start to diminish on Sunday and especially Sunday night. Lighter winds are expected early next week and they may be southerly. Mid-week northerly winds are expected to increase again. MKK

FIRE WEATHER

A warming and drying trend will peak Thursday and Friday. Interior highs will reach near 90 with RH sticking in the the teens. ERC values will return close to the 80th percentile, representing moderate to high fire danger. Said percentiles are near record breaking for the time of year but remain much lower than peak summer.

Beyond just warm and dry conditions, a very positively tilted trough over the central California Coast will promote moderate northeast winds today, mostly restricted to high ridges as far north as central Humboldt County. Winds will be locally strong in southern and eastern Lake County with gusts mixing in the afternoon over 25 mph. These winds will promote areas of critical fire weather with a Red Flag warning in effect. Tonight the winds are expected to continue over the ridges of eastern and southern Lake county so upgraded and expanded the Fire Weather watch for these locations. It looks like the winds will increase earlier than expected so have started the RWF at 10PM. Northeast winds will weaken Friday, but remain gusty along high ridges at least through the morning. Conditions will be exceptionally dry Friday in the wake of the winds with many interior locations seeing single digit RH. MKK/JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... Red Flag Warning until 2 PM PDT this afternoon for CAZ418- 419.

Fire Weather Watch from late tonight through Friday afternoon for CAZ418-419.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 PM Friday to 9 PM PDT Saturday for PZZ475.