A much cooler weather pattern will settle into the region over the weekend. Saturday’s high will drop into the 50s and then into the 40s for Sunday and Monday. A cold low pressure center is moving down out of the northeast and will sweep through the eastern side on Nevada, and as it pushes down it could bring a few snow showers into our area on Sunday, although most of the precipitation is likely to stay on the eastern side. Unfortunately, it is not a good precipitation pattern for the mountains, although the eastern slopes could get some enhancement on Sunday.

We’ve been talking about jet streams of late. And even though we often talk of the jet stream as a single entity, there are really four of them typically circling the globe. There’s a polar and a sub-tropical jet stream in each hemisphere, each generally following a sinuous path from the west to the east. The polar jets are lower in the atmosphere (generally 25-35,000’ altitude vs. 35-60,000’ for sub-tropical jets), and they tend to be stronger in the winter when the contrast of the polar and tropical airmasses is the greatest.

And at times you can get other types of jet streams, including one in the summer that goes the opposite direction (east to west) down in the tropics, and low-level jet streams can affect the strength of winter storms hitting the west coast. That’s one kind of jet stream that the land does have a large effect on.