Terpeast

First mention of dec 2 system from LWX Forecast confidence decreases markedly by Tuesday. On the synoptic scale a shortwave embedded within a much broader longwave trough encompassing much of the CONUS is expected to lift northeastward out of the base of the longwave trough and interact with what should be a sharp baroclinic zone in place along the East Coast. Various sources of both deterministic and ensemble guidance show a large amount of spread with respect to what will ensue with this system. Some solutions show large precipitation totals, while others show little precipitation at all. Some show snow, some show a wintry mix, and others show plain rain. As is typical, temperatures look to be colder the further north and west one goes, so those locations have a greater chance to experience wintry precipitation if it were to occur. It`s too early to get into details at this point, but this system will be one to monitor over the next several days, as it has at least a chance to bring portions of the area their first wintry precipitation event of the year.

Hit 70 today. Probably the last one for a while.

It's early and cold air is iffy down here, but the midwest storms today and Nov 30 will pay a role in laying down snow cover and reducing modification of cold air setting us up for the threat next week.

It will be interesting to see whether this split forcing, if it happens, is a continuation of the VP standing wave over the MC, or is a second wave propagating eastward from MJO 6>7>8>1. There is agreement that the first (current) wave is going to propagate into 8 and 1 in the coming days (according to both GEFS and EPS hovmoller charts), which makes sense as we're already tracking some wintry threats on the way next week. (and when I say wintry threats, I'm not saying it's going to snow imby, just talking generally over a broad area in the E and NE)

Nice looking runs, but let's not get too excited until we get within 5 days. It's not even December yet, so let's hold until Black Friday. If the models are still doubling down then, this may be a real threat to contend with.

I think it might be later than that, if we even see sustained phase 8.

It looks like this is our first window (I'm on the very very southern edge of it so not expecting much). After this first window, the PNA looks to go pretty deeply negative then rise back to neutral-ish by mid-month. Then we should get another window sometime after that.

The return of the blob? Btw, thanks for posting the model forecast change loops. If you look to the left at the north pacific, notice the lines tightening meaning the models underestimate the pac jet and it gets stronger as it gets closer in time. That nudges north pac ridging to the north and east into the EPO domain, which means more cold for midwest and possibly the east. The SST change map also seems to reflect this tendency.

Yeah, I saw that. It’s actually “ahead” of the euro now.

That's the dream ain't it?

And so is the tropics. Same run tries to brew a hurricane in the Caribbean in fantasy range.

Same page, I'm still thinking January is the cold month for the east. Best chance for MA snows before Feb torch. Dec isn't really in play for us down here imho

Here’s hoping for the best case scenario - current wave propagates east, lays down tracks for warmer surface/subsurface waters for the next mjo wave going well into 8 and 1 in jan/feb, while confining the nina to east based. Could turn out to be a fun winter if that happened. EPS tries to do this, but GEFS has been better with MJO. We shall see

Careful, we don’t want the nina to fade too fast. Winters with a nina that quickly fades to neutral by Jan tend to be less snowy than those that fade more slowly.

As I said, we will also want to see GEFS as comparison, not just the EPS

Yeah, gefs is slower and stronger going into 7, but I don’t really pay attention to what happens after that (the purple part) - too far out to have any real skill. But the gefs hollmover shows forcing weakening over the MC and moving east quickly through the pac basin past the dateline over the next week, and then cycle back to 6-7-8 soon after.

For future reference, based on MJO verification over the last 30 days, GEFS is really the one to watch when MJO is medium to high amplitude. And it’s not even competitive.

For future reference, based on MJO verification over the last 30 days, GEFS is really the one to watch when MJO is medium to high amplitude. And it’s not even competitive.

Same in ashburn

And the lake effect belts should be in for a fun time with the waters still being pretty warm

This isn’t true. For every example a pattern started in dec and persisted, I can come up with a few counter examples when the pattern changed in January.

0.17”, 51 degrees

Don’t know why people are jumping off the ledge a week before Thanksgiving. Acting like it’s game over for the whole winter when models are still struggling to get the longwave trough and ridge placements more than 10-12 days out. We will still get our chances/patterns. Maybe not the first half of dec, but I didn’t think that was ever in play to begin with. And I’m saying all this as someone who is calling for a “mid” kind of winter where we may only barely break double digits. And FWIW last winter the PV was stronger than normal, and we still got our cold air and snowfall.

I think the differences are mainly noise on such a forecast product like the weeklies that far out.