WidreMann

Oof, 00z GFS sucks for us. We get a couple days of really cold air, but otherwise just rain storms.

Euro is moving in that direction a little bit too, but not nearly as much. It seems that the key to the GFS behavior is that it brings down a lot of northern stream energy and phases it with the southern stream. The earlier runs had a great deal of stream separation. I've seen the models happily phase at this range, only to reverse later on (usually to slow down the southern stream). So I think we actually have a good shot at having the southern energy amp up as or after the cold is arriving. Or it could get crushed. We'll see.

Might be the GFS northern stream bias, or might be a real trend, but the coastal developing along the Arctic front has disappeared on 18z and looks that way on 00z as well. It's still so far out that I don't feel concerned either way.

No need to use the 540 line in the modern era.

What are the snow totals? That's insane enough that I don't believe it'll happen as such, but I believe we will get something.

How does it look at the surface? Weather.us no longer has the free maps...

1052 is much more likely in the new pattern.

12z GFS continues to show ridiculously cold temperatures in the LR. A low of 20 in Pensacola, FL on the 25th? Insane. It also seems to agree with the Euro on the rain-to-snow scenario in the 8-9 day range. With that much cold air coming down, I absolutely believe the possibility of a backside snowstorm. We just gotta keep the moisture.

GFS seems pretty locked on a cold pattern starting next week. Euro is less bullish as it's got a lot of garbage in the Pacific. I think despite the failure of the SSW to cause a full split and reversal of the zonal mean winds, it has weakened all that substantially and that may be enough to give us a wintry pattern for a while. I have no idea what the MJO will contribute since it's about to go into the COD and then maybe loop back (we can hope). I'm appreciating that this cool down we're having now has been more robust than it looked last week. I was not expecting lower 20s any time soon.

Great Lakes low says NO.

The fact that we had a 70 degree day in early December doesn't really indicate that the pattern for the storm was worse. We had much stronger confluence over SE Canada and the NE US and the HP center was much further south and stayed longer.

We had a much better pattern in December than we do now.

This is not a good pattern for a winter storm here. There is some cold air around and there is a storm system, but the heights are high over most of central and eastern North America. There's a big ridge right on the tail of this thing. While there is a cold high, we have limited confluence and a progressive pattern. More likely than not, we'll see the FV3 18z solution or worse.

About 28".

That may be true now, but there have definitely been events, even since 2000, where the CAD expanded much further south and east.

Amazing how so many positive factors can be off by just enough to result in a terrible pattern for the foreseeable future.

I don't follow SH weather patterns. What do you think is the cause?

If the vortex doesn't split, then it won't matter. What we're looking at is that the vortex may split briefly, but then it recongeals. That's what the GFS shows. If that's what happens, then I don't think it'll help us much.

I don't know why anyone was forecasting an epic winter. But they did generally agree that December would be the warmer month. I think the warmth was just delayed and so now it extends into January. MJO is looking quite healthy and not in any risk of heading into the zone of death. It's very likely to make it to phase 8 and 1 with some strength. I think we're just going to have a crappy start to January.

Depends on what parameter. I wouldn't trust them on exactly how much rain/snow will fall or the exact temperature, but they've actually improved enough over the past decades that they're not usually too far off even in the 6-10 day range. Remember how the models had the December 9th storm more than a week out?

The GFS is moving towards showing a split PV, with the weaker lobe in SE Canada (approximately). GEFS ensemble mean has dropped 10mb zonal mean wind at 60 N for the past few runs. Euro has wavered the last 4 days, but still shows a minimal split of some sort. We are having an SSW of some sort, but whether it will be big enough and propagate downward enough to give us a cold January and February remains to be seen. Euro and GFS LR are seasonable, which in these very warm years, is probably pretty good.

We live in the south. Wall-to-wall cold has never been the norm.

EPS average has some snow depth, but less than half an inch in Raleigh. I think it's too early for this to happen.

But it's 384. The 384 from yesterday's GFS (which is now 360) had significant ridging on both the east and west coasts, with a minimal trough in the middle.

I don't know what y'all are looking at. All of the indices except the PNA are going in the wrong direction or are neutral. CFS is blowtorch across most of the continent as we head into January. The SSW probably won't result in a full PV split and may not propagate downward. The models are slowly backing off that solution. There's a chance of a cold January, but it's far from likely TBH.