We will finish up 2017 on a dry and warm note, although we do finally see a chance of a few showers coming a couple of days into the New Year. High temperatures will peak near record level (low 60s) through Saturday before a weak cold front moves through the region Saturday night. That front isn’t substantial enough to do more than drop our highs back into the 50s and kick up some mild to moderate winds. As we start 2018, we finally get a couple of weak to moderate systems coming through the region, giving us a slight chance for some valley rain and higher mountain snow, but I don’t expect major amounts of either to fall with those systems.

500 mb

500 mb chart valid Wednesday, Dec 27 4 pm PST

So why does the weather in the eastern US seem to be the reverse of ours? First, you have to look at what brings warm and cold temperatures to an area. Although it’s a gross simplification, you will typically get cold air with a trough of low pressure, and warm air with a ridge of high pressure. The deeper the trough (the lower the pressure), the colder it is, and vice versa for the high. But why should cold weather east result in warm weather here? I’ll tell you tomorrow.