December 2021

[donsutherland1]

1 hour ago, wdrag said:

In the mean time???  Maybe I'm wrong, but another climate forecaster pointed out what appears to be a developing stratwarm in nw NAM the next couple of weeks (GEFS).  Is it true?  AND,  the impact on USA weather?  Presuming the same delays here as always at least 2-4 weeks after occurrence (late Dec?).  I am curious. Need something to jar this pattern back to something eventually more favorable for winter (after this -NAO disappears next week). 

So far, no such event is showing up on the EPS forecast, which goes out two weeks. At present 1 mb, 10 mb, and 30 mb are all near normal or cooler than normal. Until there is consensus, my confidence in a stratospheric warming event remains low.  That the MJO has been stuck in phases 3-5 (currently 4) for almost all of November isn’t helping things either. I agree with you that we need something to trigger a pattern change that would yield more sustained wintry weather.

[snowman19]

20 minutes ago, donsutherland1 said:

So far, no such event is showing up on the EPS forecast, which goes out two weeks. At present 1 mb, 10 mb, and 30 mb are all near or cooler than normal. Until there is consensus, my confidence in a stratospheric warming event remains low.  That the MJO has been stuck in phases 3-5 (currently 4) for almost all of November isn’t helping things either. I agree with you that we need something to trigger a pattern change that would yield more sustained wintry weather.

@bluewave We are in a very stagnant pattern for sure Don. And all that talk last month of a rapidly dying La Niña were wrong. We are about to see it go into moderate territory: 

 

[MJO812]

Day 5-15  500mb mean on the  0Z EPS

Phase 6 in - ENSO years in December are not warm. 

 

[EasternLI]

Just to be clear. The stuff I'm referencing would be longer term. 2nd half of December. However, could be potential for a fun holiday season if things work out nicely 

[EastonSN+]

Found the NAO forecast interesting. Large spread. Also the PNA looks like it's going to head positive again after a brief dip. MJO doing this?

[bluewave]

5 hours ago, EastonSN+ said:

Found the NAO forecast interesting. Large spread. Also the PNA looks like it's going to head positive again after a brief dip. MJO doing this?

 

Yeah, I think the PNA trying to go positive again is a result of the MJO slowing  in phase 6.  MJO812 posted the composite for a La Niña a few posts back. The link that has the ENSO specific MJO phases is below. The phase 6 during a La Niña in December has more of a +PNA and trough near the Northeast. But since we have such a fast Pacific flow with a +EPO, it may end up favoring New England more while we still remain in phase 6. The big question is how long  the MJO lingers in phase 6? At the very least, it may slow down any transition to a more zonal flow during the 2nd week of December.

https://www.frenchscotpilotweather.com/mjo

 

 

 

 

 

 

 

[Eduardo]

2 hours ago, bluewave said:

Yeah, I think the PNA trying to go positive again is a result of the MJO slowing  in phase 6.  MJO812 posted the composite for a La Niña a few posts back. The link that has the ENSO specific MJO phases is below. The phase 6 during a La Niña in December has more of a +PNA and trough near the Northeast. But since we have such a fast Pacific flow with a +EPO, it may end up favoring New England more while we still remain in phase 6. The big question is how long  the MJO lingers in phase 6? At the very least, it may slow down any transition to a more zonal flow during the 2nd week of December.

https://www.frenchscotpilotweather.com/mjo

 

New run more +PNA around December 7th

Old run

 

 

 

PAC jet is killing any chance for run-to-run consistency though.  Picture holding a piece of paper in front of a water cannon and trying to predict on which side of the stream it would end up.  Total crapshoot.   Barring some odd “white swan event” (like a crazy SSW), it’s gonna come down to whether the Niña overwhelms the MJO progression into the better phases.  It’s a close match and I’d expect some more flipping and flopping before we settle on a solution.  

Any expressions of confidence on any outcome here are mistaken and everything’s on the table. The safe bet IMO is something similar to last year; we’ll have our chances, but there’ll be boring periods too.

[EasternLI]

41 minutes ago, bluewave said:

The La Niña standing wave in MJO 4-6 this fall has been very persistent. The last wave weakened in phase 6 back in October. So the same pattern may be at work now that we are seeing the forecast for it to weaken in phase 6 again.

 

 

I actually view this as a good thing. Lines up better with the good la nina analogs then the bad ones. Bad ones would be like 2011. That was further west into the IO in autumn 2011. Which seems to be a key reason for that winter playing out how it did, according to some reading. Other years look much more similar to what we have this year. I won't post those for risk of being severely weenie'd lol. 

[EasternLI]

6 minutes ago, bluewave said:

Unless we eventually get some substantial help from the -NAO and -AO this winter, the +EPO and Pacific Jet will continue to run the show. You can see the ensemble means back to a flatter PNA ridge by December 7th. So the weakening MJO 6 might not provide enough pushback against the Pacific Jet.

 

I agree with that. I'm not bullish on early December. It'll be really interesting to see how it goes later on. 

[snowman19]

1 hour ago, bluewave said:

Unless we eventually get some substantial help from the -NAO and -AO this winter, the +EPO and Pacific Jet will continue to run the show. You can see the ensemble means back to a flatter PNA ridge by December 7th. So the weakening MJO 6 might not provide enough pushback against the Pacific Jet.

 

 

[MJO812]

1 hour ago, snowman19 said:

 

Let's see how bad DT busts

His worst bust was boxing day 

[Stormlover74]

18 minutes ago, MJO812 said:

Let's see how bad DT busts

His worst bust was boxing day 

I'll take him over joe b

[EasternLI]

Interesting little recurving Invest in the west pacific. Could help explain the MJO Phase 6 interference. Or maybe it doesn't recurve, who knows. Interesting nonetheless.

 

[SnoSki14]

12 hours ago, MJO812 said:

Let's see how bad DT busts

His worst bust was boxing day 

If December doesn't follow the typical Nina narrative then why should the other months follow it. 

That being said you don't want to get completely shut out in a Nina December otherwise it doesn't bode well for the rest of winter. 

[snowman19]

1 hour ago, bluewave said:

It may just be the rapid expansion of the Western Pacific warm pool. The MJO has been lingering in phases 4-6 all fall. We have been seeing this pattern more and more in recent years. The MJO stalled near the Maritime Continent has been contributing to the record rains in Australia.
 

 

The current healthy -ENSO and background state in the PAC strongly supports the MJO continuing to stay stagnant in phases 4-6. Every attempt by the models to advance it beyond phase 6 has failed since September 1st

[Allsnow]

I don’t see much help from the mjo or strat anytime soon. Perhaps some jet retraction mid month? 
 

 

Eps continues to keep that torch look in the 11-15 day  with it not moving up in time. With that said, it’s still a very meh pattern for snow/cold

[EasternLI]

1 hour ago, bluewave said:

It may just be the rapid expansion of the Western Pacific warm pool. The MJO has been lingering in phases 4-6 all fall. We have been seeing this pattern more and more in recent years. The MJO stalled near the Maritime Continent has been contributing to the record rains in Australia.
 

I can totally see that as being a contributing factor to such events. Absolutely. However, the MJO staying in phases 4-6 for the autumn is not surprising for me. As that's a climo location for la nina events in the autumn. The MJO is supposedly dormant during autumn so the la nina base state is that area. Which is what we're seeing there IMHO. 

[bluewave]

9 minutes ago, Allsnow said:

I don’t see much help from the mjo or strat anytime soon. Perhaps some jet retraction mid month? 
 

 

Eps continues to keep that torch look in the 11-15 day  with it not moving up in time. With that said, it’s still a very meh pattern for snow/cold

Yeah, the day 11-15 EPS looks like a classic 0z to 12z run windshield wiper effect. One run tries to pump the Western ridge with more of a MJO 6 influence. The next run leans more on the fast Pacific Jet and tries to flatten the ridge. But the storm track should be similar either way with lows passing through the Great Lakes every several days. Brief warm ups ahead of the lows followed by cool downs behind.

[EastonSN+]

10 minutes ago, bluewave said:

Yeah, the day 11-15 EPS looks like a classic 0z to 12z run windshield wiper effect. One run tries to pump the Western ridge with more of a MJO 6 influence. The next run leans more on the fast Pacific Jet and tries to flatten the ridge. But the storm track should be similar either way with lows passing through the Great Lakes every several days. Brief warm ups ahead of the lows followed by cool downs behind.

Looks very boring and relatively dry. Heck even in 11/12 we already had a 4 to 8 inch snowfall in the books in October.

[MJO812]

14 minutes ago, EastonSN+ said:

Looks very boring and relatively dry. Heck even in 11/12 we already had a 4 to 8 inch snowfall in the books in October.

And we know how that winter turned out to be 

[MJO812]

26 minutes ago, bluewave said:

Yeah, the day 11-15 EPS looks like a classic 0z to 12z run windshield wiper effect. One run tries to pump the Western ridge with more of a MJO 6 influence. The next run leans more on the fast Pacific Jet and tries to flatten the ridge. But the storm track should be similar either way with lows passing through the Great Lakes every several days. Brief warm ups ahead of the lows followed by cool downs behind.

Cmc and gefs show a better pattern and the eps have been trending colder everytime we get closer. Eps have been too warm in the long range.

I still think we will get snow next month.

[bluewave]

4 minutes ago, MJO812 said:

Cmc and gefs show a better pattern and the eps have been trending colder everytime we get closer. Eps have been too warm in the long range.

I still think we will get snow next month.

You can see the gradient favoring New England at least in early December.

 

 

[MJO812]

10 minutes ago, bluewave said:

You can see the gradient favoring New England at least in early December.

 

 

Looks like a SWFE. We need a bigger press for our area. 6z gefs was a positive step .

 

[Allsnow]

7 minutes ago, bluewave said:

You can see the gradient favoring New England at least in early December.

 

 

Yeah, this shot of cold air will favor New England more as the angle is best for them. The eps did a good job sniffing out that cold shot around the 5th

[EastonSN+]

26 minutes ago, bluewave said:

You can see the gradient favoring New England at least in early December.

 

 

Worst part about this look, we are at or slightly below normal on temps (no energy savings) but southwest of the storm track. At least the storms will be weak and fast moving.

[snowman19]

1 hour ago, bluewave said:

Yeah, the day 11-15 EPS looks like a classic 0z to 12z run windshield wiper effect. One run tries to pump the Western ridge with more of a MJO 6 influence. The next run leans more on the fast Pacific Jet and tries to flatten the ridge. But the storm track should be similar either way with lows passing through the Great Lakes every several days. Brief warm ups ahead of the lows followed by cool downs behind.

One thing to keep in mind is an article HM wrote several years ago, A -QBO/Niña combo favors a flat Aleutian Ridge from Dec-Mar. On the other hand, A +QBO/Niña combo favors a poleward Aleutian Ridge from Dec-Mar

[snowman19]

14 minutes ago, snowman19 said:

One thing to keep in mind is an article HM wrote several years ago, A -QBO/Niña combo favors a flat Aleutian Ridge from Dec-Mar. On the other hand, A +QBO/Niña combo favors a poleward Aleutian Ridge from Dec-Mar

@bluewave Here is the discussion on this with Griteater and Don Sutherland from last fall, 2020: https://www.33andrain.com/topic/1959-met-winter-20-21-pattern-drivers-evolution/

[EastonSN+]

1 hour ago, MJO812 said:

And we know how that winter turned out to be 

Yeah only one 3 to 6 in her in January. 

Can't complain only experienced 6 below average snowfall winters this century!

[LibertyBell]

1 hour ago, bluewave said:

You can see the gradient favoring New England at least in early December.

 

 

why is it so hot out west? you'd expect a big trough in the east with so much heat out in Colorado....Denver hasn't seen a single flake yet

 

[LibertyBell]

3 hours ago, bluewave said:

It may just be the rapid expansion of the Western Pacific warm pool. The MJO has been lingering in phases 4-6 all fall. We have been seeing this pattern more and more in recent years. The MJO stalled near the Maritime Continent has been contributing to the record rains in Australia.
 

 

November 1995 being referenced for Australia, we're going to need that kind of blocking this season