AbbyJr

It is but there is also less data inputted into it if I’m not mistaken.

So your saying the Spire has access to more data in the North Pacific than the other models?

Agreed. This is timeframe we normally see a rug pull. Sometimes it's temporary and sometimes not. But it's a complex pattern.

At first I thought it was something the GFS just made up. But its concerning that the Euro trended in the same direction.

Unfortunately, that strong low might be a feature the models did not pick up on earlier. If that's the case then it's game over for the top tier arctic blast. Still time to revert to the colder solutions but latest trends have me worried.

You could be right but there is no reason to believe that as of now. There's also no reason to believe the models won't revert back to the colder solutions next run. There's really no way of knowing what's going to happen. But it's concerning seeing the Euro trend towards the GFS on the 500mb pattern shift. Maybe you're not as concerned as I am and that's fine. But this arctic blast is not yet a lock.

But the surface stuff is reflected by the 500mb stuff so it's ultimately the most important factor. The Euro was only still somewhat good because it only shifted the polar lobe slightly further east. Shift it much more east and the arctic air misses us entirely. So you can't just focus on the surface details. You must first be concerned with the upper level pattern that drive the surface details. There's more than one factor at play.

Where do I find the graph cast model?

Really? While it wasn't as bad as the GFS, it certainly trended towards it. Here is the run to run change for both the GFS and Euro:

Seems like that deepening low north of Alaska is shifting south and resulting in a weaker GOA block and shifting it southeast. Less amplification and the polar vortex taking an eastward shift is the result. Actually, the 00Z Euro looks identical to the GFS. This happened last December around leading up the arctic blast. After one or two bad Euro runs, it reverted back to the cold solution and eventually the GFS followed suit. Who knows if that will happen this time. It's a very fragile setup to say the least.

Is this a bad trend or just the typical temporary rug pull?

What do you mean by under-dispersed?

If the 00Z Euro holds strong tonight, I won't be worried. But if it falls apart then I'll start to get nervous.

But it is certainly trending the polar low further east. Looks very similar to the operational. But it's the GFS so who cares.

Not necessarily. The Euro backed off for a run or two last winter and then reverted back to the cold solution. It's a fragile setup.

The GEM has been the warm outlier between the Euro and GFS. Out of three, the Euro is statistically the best performing model. Not sure what the 00Z Euro will do tonight. If it holds strong, then I'm not worried.

Especially since the 18Z Euro control looked better at 144 hours than the 00Z GEM at the same timeframe. It's really a game of inches here where the slightest adjustments to the GOA block and polar lows can be the difference between extreme cold and a milder outcome. Time will tell but I'm not yet buying the GEM solution at all.

Good chance it's a warm outlier but I'll start to get nervous if the Euro follows suit tonight. The 00Z GFS was much improved. Looked similar to the 12Z Euro today. The model ride continues.

This block looks sketchy? Not sure what you're talking about. Looks pretty strong and solid to me.

Of course it can happen but we are 7 days out. It's hard enough to predict snow around here within 48 hours.

But did anyone actually believe that there would be 4 days straight of snow?

December 28, 1968 is on the list.

If we do then you can thank the SSW. There’s no chance we get sustained cold this winter without it given the strong El Niño state.