We have another warm low pressure system coming up from the south, but it appears that it will fall short of getting close enough to bring us a repeat of the showers we saw Monday. We will likely see some clouds out of the deal on Friday (before clearing out Saturday), and it’s not impossible the mountains well south of Lake Tahoe could see an isolated shower, but any substantial precipitation should be contained to the southeastern third of Nevada. Temperatures will start out Friday in the mid-50s and could climb to the mid-60s by the middle of next week.

Cloud seeding tower at the summit of Alpine Meadows ski area near Lake Tahoe, California. (Lauren Sommer/KQED)

Cloud seeding tower at the summit of Alpine Meadows ski area near Lake Tahoe, California. (Lauren Sommer/KQED)

Yesterday, I mentioned that clouds need a nucleation site in order to kick start the precipitation process. Cloud seeding provides that. Silver iodide (AgI) is an ideal nucleation site. Generators stationed on the mountaintops burn a propane/silver iodide mixture which injects microscopic particles of AgI into clouds that are already saturated and are cold enough to contain the supercooled water droplets. Any clouds which meet those criteria are probably already producing some precipitation. Cloud seeding is designed to make those clouds more efficient at producing precipitation.

 

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