A Difficult Forecast

Monday, November 6, 2011
12:55 P.M.

Forecasting is generally a low-stress profession, but there are times when you know everybody is watching your every keystroke, and this is one of those times. The models look a little bit warmer today, but not much. I seriously doubt that we will see lowland snow with this storm, though. The foothills of the Cascades could get some, and the mountains will be hammered, but at this point, I think the snow level will stay above 1,000 feet or so. But never fear, the latest model run from the Euro showed some extremely cold air diving down from the arctic beyond next week. I’ll get to that later.
The European model still points a cold scenario, although today’s 12z run isn’t quite as cold as the one from yesterday. Let’s compare the two. Here’s yesterday’s plot for hour 168.
Valid 04:00 am PST Sun, 13 Nov 2011 – 168hr Fcst – ECMWF (Euro) 12z 500mb height and SLP

Here’s the one from the 12z run this morning.

Valid 04:00 am PST Sun, 13 Nov 2011 – 144hr Fcst – ECMWF (Euro) 12z 500mb height and SLP 
The low looks significantly weaker in the most recent run, but I’m not sure if this is actually the case. The European model has frames every 24 hours, which is really annoying. The low was probably around 975-980 millibars or so, but this frame shows it at a time when it is starting to weaken. You can get more detailed information from the ECMWF, but it costs lots of money. The NOAA models are free. Still, I recently found a website that has some good model information for the ECMWF model, which you can find here. I have it labeled on the side as “Allan Huffman’s Weather Model and Data Page.”
The GFS models show a strong front dropping from our north, which is a totally different scenario than what the ECMWF is showing. The ECMWF has been much more consistent, so I am leaning toward it as opposed to the GFS. Still, here is the GFS from the UW this morning.
Valid 10:00 am PST Sat, 12 Nov 2011 – 126hr Fcst – UW 36km 12z WRF-GFS 3-hour precip, SLP
This model shows that low heading up into the Queen Charlotte Islands. I’m sticking with the Euro for now.
The location of the low will be crucial. South of us, and we will get a cold rain with low snow levels. If it was January, I’d be worried/excited about a major snowstorm, but alas, it is only November. If it goes slightly north of us, we could have our first windstorm of the season.
I said I’d brush on a possible arctic outbreak in the extended, and that is what I will show you. The Euro has been fairly consistent with this feature, and the latest 12z run was very exciting.
Valid 04:00 am PST Tue, 15 Nov 2011 – 192hr Fcst – ECMWF (Euro) 12z 500mb height and SLP 
 
Look at all those low heights! That would be something. But alas, it is in the extended, and that means it is up for grabs. The models have definitely been trending toward a colder pattern though, particularly the Euro, so it bears watching.
I have to head off to class now, I did all of this in 25 minutes. I was in warp speed mode!
Charlie
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