The damaging winds from Friday should moderate Saturday, but will still be very brisk. Scattered rain showers and southwest winds 15-25 mph (gusts could be as high as 45) will be the operative Saturday forecast. Snow levels will probably stay above 8,000’. There will be a slight break Saturday night before another storm system comes through Sunday afternoon into Monday. That second storm system will be a little colder, with snow levels dropping down to near Lake Tahoe.

Damonte Ranch. Courtesy Steve Shifferdecker

Damonte Ranch. Courtesy Steve Shifferdecker

Not everybody minded the wind. Photo courtesy Taylor James (and Benson the dog.)

Not everybody minded the wind. Photo courtesy Taylor James (and Benson the dog.)

Surf's up! Courtesy Martin Gollery

Surf’s up on Tahoe! Courtesy Martin Gollery

Our present storm notwithstanding, I don’t need to remind anyone how dry it has been. Steve moved here from Las Vegas, and something surprised him” “Upon moving to Reno, I noticed my skin started to “crack” and a couple of minor nosebleeds. I said to myself, “There ain’t no way it could be drier here than the ……”desert”. But apparently it is MUCH drier? Less humidity? How is this possible?” Actually, it is a fair bit drier here than in Vegas. But relative humidity doesn’t really tell the story as much as dewpoint. Before our rains started, our dewpoint was in the low teens. Las Vegas had a dewpoint of 39 at the same time. They just have more water in their air, a function of their elevation and proximity to the moister air in Mexico.

Yep... it's dry here.

Yep… it’s dry here.

I mentioned the dewpoint. That’s the temperature at which the parcel of air you are measuring will become saturated (100% relative humidity). The more moisture in the air, the less you have to cool it to become saturated, so it is a much better measure of the amount of water vapor in the air than relative humidity. Air that has a dewpoint of 20 degrees F needs to cool to that temperature before condensation (saturation) occurs, and dew forms (hence the name). If the dewpoint is 40 degrees F, it means it has more moisture in it than air with a dewpoint of 20.

How is dewpoint more useful than relative humidity? If you have a parcel of air where the dewpoint is, say, 20 degrees, the relative humidity can go from 100% at sunrise (if the temperature is 20 degrees) to about 25% in the afternoon when the temperature rises into the 50s… all without changing the amount of water in the air. It’s one of the reasons that we don’t generally “forecast” the humidity, because it changes so much in any 24 hour period.

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