It’s going to sound a lot like yesterday’s forecast. A flat ridge of high pressure will keep us dry through the weekend, while allowing variable amounts of cloudiness to drift across the region for the next several days. High temperatures will very gradually increase from the low 50s Wednesday to the upper 50s by Friday, and will hover in that range through the weekend.

Taking a peek ahead, there is some indication that come Thanksgiving week we could get our (nearly) annual Holiday week storm. Stay tuned.

water cycle

So just how does a “rain shadow” stop rain and snow from making it to our side of the mountains? In order to see what stops the rain, you have to understand what makes rain (and snow) in the first place. Water vapor in the air has to first condense in order to make a cloud, and to condense the air has to cool. If you take moist air and force it upwards, the decrease in pressure makes it colder (it’s called adiabatic cooling). So in oversimplified terms, if you take moist air and make it go up, you get clouds and rain.

Tomorrow, I’ll tell you how mountains play into that.