The pattern is setting us up for a very windy early weekend, raising concerns about the fire danger. A trough of low pressure off the Pacific Northwest will split off some energy and push it onshore Friday night, bringing a cold front that will drop temperatures from the low 90s Friday afternoon down to the low 80s on Saturday. While a shower north of the Reno area isn’t impossible, it’s more likely it will be a dry event. Winds will increase Friday night out of the southwest 10-20 mph with gusts to 35 mph, and will increase Saturday with gusts possible over 45 mph. A Fire Weather Watch kicks in 4 am on Saturday and runs through the day.

night clouds

So how do clouds affect radiational cooling? Clouds don’t only suppress the effect… they eliminate it all together. If the radiation from the ground doesn’t have a free path all the way into space, the ground will not lose any radiational heat, and will just match the temperature of the air. It’s another reason why you almost never see frost on the ground on or after a cloudy night.

If you really want to get into the subject, Google “black body radiation” and be prepared for your eyes to glaze over.

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