Saturday will be one of the windiest days we have seen in months, bringing impacts to recreation and travel and creating fire danger.
Not only is there a Fire Weather Watch up for Saturday, but there is also a High Wind Watch, where wind gusts could top 50 mph for a long period of time.
Wind prone areas could see gusts up to 70 mph. Wind speeds will be strong enough to take down tree branches and cause power outages.
It will already be breezy by sunrise Saturday, with gusts in the 20s. Unfortunately, there is a good chance the balloon races will be canceled on that day as a result of the wind.
However, wind speeds will be lighter Sunday afternoon. There is a possibility it could still be breezy Sunday morning as well, but not as bad.
A trough will expand southward on Friday, followed by an upper-level low on Saturday.
Winds will start to pick up on Friday and then really ramp up on Saturday.
The lows will tighten the pressure gradient with a ridge to our south. Temperatures will drop from the low 90s on Friday to the low 80s on Saturday, and the 70s on Sunday.
Wind is related to temperature and pressure. With the ridge close to the low, the pressure gradient will be tight.
Downsloping winds are also possible with an inversion at 700 mb. An inversion is a layer of stable air, with warm air above cooler air.
This is a key ingredient for downsloping winds. There also needs to be a strong jet perpendicular to the Sierra.
You can think of a downslope wind as water flowing from a sink or a waterfall. With a waterfall, the river water is moving quickly, and then it pours over the cliff with nothing to stop it.
When there is a lot of turbulence in the air, there are also a lot of eddies with rising and sinking motions. As the air sinks, wind speeds accelerate over the mountain.
Stay tuned, as the High Wind Watch will likely be replaced with either a High Wind Warning or Wind Advisory. The latter is not as damaging, but an advisory will still cause problems.
High Wind Watch is in gold, a Wind Advisory is in teal.
The lows will also come through dry, increasing fire danger.
Skies will be clear through the weekend, with the best chance for rain staying well north of Reno.
Relative humidity values will range between 10-20%, with wind speeds being enough to spread fires rapidly.
Most fires are human-caused, so please be extra careful. The winds could also lead to blowing dust.