Sunday Extreme Heat, Fire Weather, Air Quality Update

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The record breaking heat wave is arriving as advertised, with temperatures rising above forecast levels in most areas Saturday, and expected to meet or exceed records for the date, and in come cases all-time temperature records today. An Excessive Heat Warning is in effect through 9PM Monday.

The high at the Sonoma County Airport Saturday was 104. Other locations further inland reached 105 or above and this before the main heat up which is expected today and to a lesser extent Monday.

Here are two model versions of the heat we’re expecting today (Sunday). They vary only in details. Highs pushing to record levels in almost all areas away from the coast. A weak onshore flow will keep stations within a few miles of the coast much cooler.

These show highs in Santa Rosa to be in the 107-108 degree range, and Healdsburg from 108-111 degrees. As we’ve been mentioning, further inland temperatures could reach or exceed 115 degrees. Even the immediate coast (Bodega Bay for instance) should reach into the mid to upper 80s.

Temperatures will be similar on Monday, but may drop by a few degrees, especially near the coast.

FIRE WEATHER

Our attention now turns to the Fire Weather Watch for late Monday into early Wednesday. Models are in agreement that this will be a “moderate” event, with winds rising late Monday and at their highest early in the morning Tuesday at 35-45 mph with some stronger gusts up to 50 mph possible in the usual windy spots like Hawkeye, Mt. St. Helena and Healdsburg Hills North stations.

Here are two forecasts for winds by early Tuesday morning. Generally winds rising to the 30 plus mph range, with some higher gusts. Highest winds to our east, but strongest winds in our area will be in the higher terrain of eastern Sonoma and Napa counties.

A Red Flag Warning will be issued today in preparation for the event. With current fires contained, the focus will be on making sure hot spots do not leave containment lines, and jumping on any new starts, if they occur, immediately. Fire agencies throughout the region are now on high alert and devoting additional staffing to the threat during the Monday-Wednesday period.

POWER

A PSPS Watch is in effect for late Monday through early Wednesday. That means PG&E may shut off power due to the intensity and or location of forecasted winds. Updates to come. Also, heat may require the California System Operator to order some rolling blackouts as the heat event progresses Sunday and Monday.

AIR QUALITY

With a stagnant air mass in place and several new large fires now adding smoke to the atmosphere, our air quality will be worsening. Models show air quality declining due to smoke from residual fires in Northern California and the Creek Fire in Madera County and the Dolan Fire near Big Sur. The Creek Fire in particular is experiencing extreme growth, and that smoke is being sent north as you can see in this satellite picture Sunday.