Fire danger will be critical Friday through Sunday, especially in the afternoon due to strong winds and dry air. What a difference a week makes. Going from monsoonal moisture one day to critical fire danger a few days later. There is a trough to our northwest, with dry southwesterly flow underneath it, which is well defined on water vapor imagery in orange. The flow around a low is counter clockwise.
The trough will also kick up our winds, making the Washoe Zephyr stronger than it normally is. Fire danger will be critical not because of lightning, but because of strong winds and low relative humidity values. This puts wind gusts in the 30’s over the weekend, primarily in the afternoon and evening hours. The fire threat is also worse in northern California than Reno.
Fire danger will be critical for the second half of the day through the weekend. Not as bad in the morning, but not perfect either. Wind gusts will go from roughly 10 mph in the morning to 35 mph in the afternoon.
Fire danger will be critical through Sunday, but still high much of next week. Mainly in the afternoon and evening hours.
Fire danger will be critical for roughly 3 -9 hours on Friday and Saturday afternoon, and 3 -6 hours on Sunday. Strong winds can be detected on the 700mb chart, on both the GFS and Euro model. Primarily in the second half of the day, and stronger in northern California than the Truckee Meadows.
A Red Flag Warning is up for the Northern Sierra Front from 1 pm -9 pm Friday through Saturday, and a Fire Weather Watch is up for Sunday afternoon and evening. This includes Washoe, Douglas, Storey, Lyon, and Lassen Counties for both the warning and watch. The Surprise Valley is also included in the fire alerts this weekend.
While dewpoints are a good measure for how muggy the air is, relative humidity values are commonly used for fire danger. Humidity values will fall below 15% Friday through Sunday. Which is very very dry! Wind will be the biggest concern, making a fire spread rapidly. During the winter, a trough brings stormy weather, during the summer it usually brings dry, windy weather.
