Weather Is (Quite A Yarn)

Good Evening:

It's quite easy to spin a really good yarn (story) out of model uncertainty.  One of my correspondents has described one of forecasts he saw as a stark reminder of the December 2013 snow storm.  Another has pointed out that the global models are all showing a big (winter) change next week.

Yesterday's GFS brought a prolonged period of cold and snow several days out.  However, the GFS ensemble shows about a 20% chance of a big rain event, with between a 10 or 20% chance of snow in the higher elevations, depending on which ensemble run you look at.

So, it's potentially very big, but it's also (more) potentially just ho-hum.

In the meantime, it should be mild through Monday before temperatures drop off substantially on Tuesday into Wednesday.  Rain is possible on Friday and if we go by the 00 GMT GFS snow will also arrive on Friday.  However, I wouldn't take down the snow boots because the latest 6 GMT update shows nothing. Moreover, the GFS ensemble shows heavier rain early the following week, not this week.

What does it mean? It means that the winter signal is not at well resolved by the models.

One further note: remember the forecast change in the Atlantic Oscillation? It was suppose to turn negative in early January.  Well, it keeps flipping from forecast to forecast. This means that we really don't know what the weather is going to be beyond the next few days as the atmospheric circulations that "count" are not well resolved or predicted.  It may not be satisfying, but it is suspenseful.

Barry Lynn