9 P.M. Tuesday, Jan. 14, 2020
Mild weather continues a few more days
I don’t know how many times over the past six months, our forecast models have predicted a reversal in the upper air pattern over North America, but it’s been often. Only once (November) did it actually happen. Now, it’s seems like it will reverse for a second time, starting Sunday.
The shift to west coast ridge/east coast trough is underway. The strong northwesterly winds aloft will definitely put us into below normal temperatures. When pattern reversals occur, they generally persist at least 2-3 weeks. But, this has been unusual winter, to say the least. When the “cold phase” hit us in November, it lasted about 3 weeks before the “warm phase” took over. And the warm phase has been around ever since. Since November 25, we’ve only had six days with below normal temperatures. For those keeping score, that’s 45 above normal days and only 6 below.
So, are we going to have a “3 week” winter, or will be longer? Good question. Answer unknown.
Old rule of thumb: After 3 weeks, if the upper air winds over us are stronger than when the cold regime began, it will persist another 3 weeks. If the winds are weaker than originally, the warm regime will return quickly.
Rest of this week
Official forecast gives Louisville a chance for rain tomorrow. I’m not buying that although some light rain will be possible over southern KY.
Another midwestern storm is likely late Friday, but it’ll be much weaker than last week’s storm. We’ll probably see periods of rain from Friday into Saturday.
Then, winter arrives Sunday! Next chance for snow comes from a weak clipper next Tuesday.