Key messages
- Very dry conditions with gusty northeast winds focused in Lake County will increase fire danger today.
- A warming trend peaking today 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 , even for the coast where marine influence remains weak. Cooler and more moist conditions build by the weekend and into early next week.
Discussion
High pressure remains over the area today bringing warm temperatures to the interior 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 this 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 today although the coast will be cooler than yesterday.
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
Mostly VFR conditions are forecast to continue for terminals of Northwest California over this TAF period. Some of the higher resolution models are suggesting a rebuild of the marine layer early this morning, yet confidence is low (~25-30 %) leading to only scattered low level cluds. Winds are forecast to continue to be calm into the morning for the valleys with breezes up to 15mph continuing near the ridgelines, especially in eastern Lake and Mendocino counties. A more robust coastal stratus layer may develop tonight and into Saturday morning.
Marine
Light winds are expected to continue through this 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 Today. 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.
Early this morning, the winds are expected to continue over the ridges of eastern and southern Lake county so the Fire Weather Warning will conitnue for these locations. Northeast winds will weaken later today, but remain gusty along high ridges at least through the morning. Conditions will be exceptionally dry today 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 11 AM PDT this morning for CAZ418>420.
NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 9 PM this evening to 9 PM PDT Saturday for PZZ475.
NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed.
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