There is still no appreciable change to the forecast over the next week or so, as a massive ridge of high pressure stays put nearly right on top of us. Cold air pooling under clear skies will give us cold mornings in the teens through Friday with afternoon highs reaching the low 50s by Friday both in the valley and up at Lake Tahoe. The similar mountain and valley temperatures reflect a strong temperature inversion which will also trap pollutants in the valleys, so hazy conditions are likely to increase over the next several days.

Yesterday I mentioned that closing foundation vents could result in trapping moisture under your house. Moisture isn’t the only reason to keep the vents open. If you live in an area with high radon concentrations, and there are many areas here in western Nevada and the Tahoe Basin where radon is a real issue, you must keep your crawlspace well ventilated all year long. It’s another good reason to insulate your sub floor instead of the foundation.

By the way, if you haven’t ever tested your house for radon leakage (it occurs naturally around here, but in widely different concentrations), then I’d highly recommend you get a self-testing kit. They are readily available and worth the minor expense.