The forecast hasn’t changed much. We’re still looking at several days of foggy, cool mornings with sunny and mild afternoons. A small disturbance will pass to our north on Friday, and there is the possibility the slight increase in winds will help mix the air up a bit, and scatter the pollution away from the ground. The PAC-12 Championship looks dry, but a little chilly. You’ll probably want to either dress in layers, or take a blanket for the last half. Here’s the break down:
In the long term, our next change in the weather will likely be Tuesday, Wednesday, and/or Thursday of next week. Yesterday, the GFS was the only model dropping a very cold trough in by overnight Tuesday into Wednesday. Today, the ECMWF (Euro) model is also pushing a trough in, but not until Wednesday night into Thursday. The GEM (Canadian) is still undecided as to whether the model will actually fall south.
Now, the reason for the title of this post. The GFS is pulling ridiculously cold temperatures in with the mid-week storm. The origin of the storm is Canada, rather than the milder Gulf of Alaska. So cold air is a real possibility. I’d buy the -1 degree temps at 850 for Tuesday, and even the -5 temps at 850 for Wednesday. That would mean mid to upper 30 high temps at the surface for those days. However, for Thursday, it is pulling 850’s down to -14 degrees! That would mean mid to upper 20 degree highs. That, I’m not buying. GFS historically overreacts with cold air more than 5 days out. Not to mention, if the trough passes to the north, we may never see a drop of rain or a change. So for right now, I’m taking temps down a little and adding some cloud cover. I’ll keep watching the models to see how they trend, but consider today’s discussion a more, “Hey this is interesting” kind of post, rather than, “wow, record cold on the way.”
— Meteorologist, Megan Taylor