Warm and dry conditions will cover our region through the rest of the week, with high temperatures reaching the 60s starting Wednesday. A broad ridge of high pressure will keep the storm track to our north, sending very wet conditions into the Pacific Northwest. We will catch some mid and high level cloudiness breaking over the ridge, but it’s very unlikely we will see any precipitation out of the deal. We stay dry through Sunday, after which some weak storm systems will bring back a slight chance of showers by the first of next week.

rain shadow 1

When you are talking about a rain shadow, many people mistakenly think that the Sierra “block” or “stop” the moisture from getting over the mountains. That’s not really how it works. Just as lifting air causes condensation/clouds/precipitation, descending air heats up, which evaporates the clouds and suppresses precipitation. As the air flows up the west side of the mountains, it increases rain and snow, but as it flows down the back side into western Nevada, it heats up and kills the precipitation producing process, unless some other lifting process is strong enough to overcome the backside drop. So the mountains don’t block the moisture… it just turns back into vapor and stays in the air, bypassing us until it gets lifted by some other process further to the east.