2024-2025 La Nina

[bluewave]

The Euro weeklies changed a few days ago following the record block near Europe. My guess is this wave breaking event helped to shift the mean ridge position across the Northern Hemisphere from around 40N to 60N. So this lifting of the ridge axis changed the whole forecast for the 2nd half of November. I don’t have much confidence in the weeklies beyond 15 days so we’ll need to see what the first week of December forecast looks like in a few weeks once it get within the more reliable EPS week 1 to week 2 range.

What we want to see happen is for early October MJO indicator to work out where the strong MJO in October is followed by a weaker MJO influence in December like we got back in 2020. This allowed other factors to win out leading to the +PNA mismatch for the -PDO and La Niña. But if the MJO comes out of the gate into the warm phases during December and the pattern begins reverting back to the stronger mid-latitude ridges we have seen all fall, then we’ll know the early indicator didn’t work out due to the La Niña being much weaker than the 2020 and earlier La Niña mismatch Decembers. We should have a good idea which one of these ideas wins out by the first week of December.

 

[GaWx]

 Here’s the latest chart showing the Euro ensemble mean’s forecasted US pop weighted HDD (on left)(green is normal): the 0Z (purple) lost 5 HDD vs yesterday’s 12Z (yellow), which helped to cause NG prices to drop moderately (now down ~4% vs yesterday)(edit: ended ~6% down at close). As Chuck knows, NG price trends are often a good barometer of changing trends of the forecasted upcoming E US wx (especially in the E US out 7-14 days): coldest days of this period still look to be 11/23-6:

[40/70 Benchmark]

39 minutes ago, brooklynwx99 said:

functionally, I feel like that composite acts like a +NAO. Atlantic flow is fast there

Yep...save ofr maybe March.

[mitchnick]

If we're ever going to get an official Niña, Gfs and Cfs2 say the cool down starts now. We'll see.

[snowman19]

2 hours ago, mitchnick said:

I meant to add this yesterday.  Euro Weeklies even bolder with placing troughing over or near Japan past week 1.

https://charts.ecmwf.int/products/extended-anomaly-z500?base_time=202411130000&projection=opencharts_eastern_asia&valid_time=202411250000

I mention it because if close to accurate, it often translates into a trough over the eastern US down the road, it brings in cooler air to help with cooling Eastern Pac sea surface temps already in decline , and it fires up @snowman19.  lol

God speed and good luck with your forecast!! I hope it works out for you

[snowman19]

56 minutes ago, bluewave said:

The Euro weeklies changed a few days ago following the record block near Europe. My guess is this wave breaking event helped to shift the mean ridge position across the Northern Hemisphere from around 40N to 60N. So this lifting of the ridge axis changed the whole forecast for the 2nd half of November. I don’t have much confidence in the weeklies beyond 15 days so we’ll need to see what the first week of December forecast looks like in a few weeks once it get within the more reliable EPS week 1 to week 2 range.

What we want to see happen is for early October MJO indicator to work out where the strong MJO in October is followed by a weaker MJO influence in December like we got back in 2020. This allowed other factors to win out leading to the +PNA mismatch for the -PDO and La Niña. But if the MJO comes out of the gate into the warm phases during December and the pattern begins reverting back to the stronger mid-latitude ridges we have seen all fall, then we’ll know the early indicator didn’t work out due to the La Niña being much weaker than the 2020 and earlier La Niña mismatch Decembers. We should have a good idea which one of these ideas wins out by the first week of December.

 

The MJO is forecast to emerge in warm phases by early December. We’ll see

[brooklynwx99]

3 minutes ago, snowman19 said:

The MJO is forecast to emerge in warm phases by early December. We’ll see

i could see a warm spell in mid December, but even the colder years like 2013 had such a spell. the beginning of Dec 2013 was a torch

we’ll have to see how the end of Nov plays out

[snowman19]

1 hour ago, brooklynwx99 said:

if we do end up going the colder route this winter (which i do not expect is the case as of now), then something like a 2021-22 / 2013-14 blend looks reasonable

general tendency towards +PNA, a -WPO that encroaches on the -EPO domain, a largely -NAO, and an elongated PV in SE Canada

If you have time, look up the 5 driest falls on record, since this fall is at #2 of all time, and see how those winters turned out. Snowfall and temps

[GaWx]

3 minutes ago, snowman19 said:

If you have time, look up the 5 driest falls on record, since this fall is at #2 of all time, and see how those winters turned out. Snowfall and temps

For NYC during La Niña (which will likely verify on RONI basis), the Dec snowfall was a very good indicator for the rest of the season’s snowfall there as @bluewaveand/or @donsutherland1showed. So, it will be quite interesting to see where their Dec snowfall ends up.

[bluewave]

27 minutes ago, snowman19 said:

The MJO is forecast to emerge in warm phases by early December. We’ll see

One of the issues the EPS has is the barrier effect. So it underestimates the longer range convection over the Maritime Continent. This is why the more amped GEFS MJO forecasts often do better when the MJO is phase 1-4 and its forecast to go into 5-6. So unless we get some type of mismatch pattern in December like 2020, then EPS will probably be playing catch up with a milder pattern since it often underestimates the long range MJO 4-6 amplitude. 

[mitchnick]

21 minutes ago, bluewave said:

One of the issues the EPS has is the barrier effect. So it underestimates the longer range convection over the Maritime Continent. This is why the more amped GEFS MJO forecasts often do better when the MJO is phase 1-4 and its forecast to go into 5-6. So unless we get some type of mismatch pattern in December like 2020, then EPS will probably be playing catch up with a milder pattern since it often underestimates the long range MJO 4-6 amplitude. 

Idk. I always look at the JMA MJO forecast as I find it's usually closer in the end to being correct than either the Gfs or Euro suites. Fwiw, JMA looks very similar to Euro vs Gfs. PRoblem with the JMA is the plots only have the ensemble JMA out 10 days vs the longer range ensembles of the Euro and Gfs suites. So there's no much of a clue for December attm.

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[snowman19]

23 minutes ago, bluewave said:

One of the issues the EPS has is the barrier effect. So it underestimates the longer range convection over the Maritime Continent. This is why the more amped GEFS MJO forecasts often do better when the MJO is phase 1-4 and its forecast to go into 5-6. So unless we get some type of mismatch pattern in December like 2020, then EPS will probably be playing catch up with a milder pattern since it often underestimates the long range MJO 4-6 amplitude. 

It was really terrible with that last winter. And in December with a negative ENSO, MJO phases 3 through 7 are all warm in the east 

[mitchnick]

50 minutes ago, snowman19 said:

God speed and good luck with your forecast!! I hope it works out for you

Gee thanks. And to think I figured you'd respond with something disingenuous. 

[GaWx]

27 minutes ago, snowman19 said:

It was really terrible with that last winter. And in December with a negative ENSO, MJO phases 3 through 7 are all warm in the east 

I have found the GEFS and Euro Ens to be the best for MJO predictions and the CFS and BoM (which were often way too amplified last winter) to be the worst. JMA/CMC in between/harder to tell since don’t go out as far. I know JB likes to look at the JMA as gold standard for MJO forecasting, which has bitten him a number of times.

[Daniel Boone]

1 hour ago, brooklynwx99 said:

i could see a warm spell in mid December, but even the colder years like 2013 had such a spell. the beginning of Dec 2013 was a torch

we’ll have to see how the end of Nov plays out

True. I think most probably don't remember that. 

[mitchnick]

24 minutes ago, GaWx said:

I have found the GEFS and Euro Ens to be the best for MJO predictions and the CFS and BoM (which were often way too amplified last winter) to be the worst. JMA/CMC in between/harder to tell since don’t go out as far. I know JB likes to look at the JMA as gold standard for MJO forecasting, which has bitten him a number of times.

I haven't read JB in years, so I was unaware of his JMA laments. Notwithstanding, I routinely see the other suites follow it. I agree with you on the CFS and BoM fwiw...they suk. But as you and I both mentioned, it would be nice if the JMA ensembles went out further. 

[mitchnick]

End of the Gefs and Geps take us to the morning of 11/30 with no real furnace in sight, US or in Canada, but Geps is surprisingly colder. 

[snowman19]

6 minutes ago, mitchnick said:

End of the Gefs and Geps take us to the morning of 11/30 with no real furnace in sight, US or in Canada, but Geps is surprisingly colder. 

What is EPS showing?

[George001]

2 hours ago, snowman19 said:

If you have time, look up the 5 driest falls on record, since this fall is at #2 of all time, and see how those winters turned out. Snowfall and temps

Im not making any claims about the result (mainly because I don’t know, I haven’t looked at this yet), but I would expand it out to top 30 driest falls. 5 is too small of a sample size. 

[mitchnick]

54 minutes ago, snowman19 said:

What is EPS showing?

It wasn'tout yet when I posted. +1-2 to -1-2 across the country at the end of the run.

Edit: Added surface and 850 anomaly maps. Looks like a front moving down from the midwest at the end of the run too.

[Stormchaserchuck1]

I'm not going to get all excited about the Winter because of a 10-day period of -NAO in November. 

12z GEFS is already going back to a -AAM look by hr384. 

[Stormchaserchuck1]

MJO poses the risk of going through phases 4-5 in early Dec

[Daniel Boone]

1 hour ago, Stormchaserchuck1 said:

MJO poses the risk of going through phases 4-5 in early Dec

I may even make good bet on that happening. Par for the course , lol

[PhiEaglesfan712]

4 hours ago, Daniel Boone said:

True. I think most probably don't remember that. 

December 2013 and December 2014 were above average, and definitely the outlier months of those winters. November 2013 and November 2014 were well below average, and of course, JFM 2014 and 2015 were the coldest post-1978.

[George001]

The guidance does look promising for the pacific, but I’m pumping the breaks unless we get much closer in and see no signs of the pac breaking down on the long range guidance. If that happens, I will start getting very excited. I do buy that we will have a window of a favorable pac, but if it is short lasting that will be extremely concerning for winter prospects. Too early to tell which scenario will verify.

[mitchnick]

1 hour ago, Daniel Boone said:

I may even make good bet on that happening. Par for the course , lol

I wouldn't get worried at this point. First of all, there are multiple variations from the Euro suite as well as the Gfs suite. They, along with other modeling, are at the link below. You can see the various different forecasts from the same suite not to mention that forecast Chuck posted was at the end of the run with low skill. 

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[GaWx]

 Overall trends since 0Z today in EPS/GEFS have been milder for late in the runs (last few days of Nov) resulting in a drop in HDDs. This helped NG prices close down 6% since yesterday. NG prices are an excellent barometer of the latest tendencies in the week 2 trend, often especially days 10-15, in E US modeled temperatures. We’ll see what tomorrow brings.

 Regardless, a refreshingly chilly (NN to BN) period looks to be on the way for much of 11/21-6 in the bulk of the E US. Enjoy!

[Daniel Boone]

5 hours ago, PhiEaglesfan712 said:

December 2013 and December 2014 were above average, and definitely the outlier months of those winters. November 2013 and November 2014 were well below average, and of course, JFM 2014 and 2015 were the coldest post-1978.

Yep. Remember them well. Feb. 2015 snowiest on Record here. Strong + TNH Pattern.

[mitchnick]

1 hour ago, bluewave said:

The EPS tends to be too weak with its MJO amplitude near the end of the effective 15 day forecast period when going into phase 4-6 like it’s showing in early December. So if we look at the VP anomalies charts they are all showing this current MJO in the IO progressing to the Maritime Continent in December but the GEFS is stronger. If there isn’t to be some type of mismatch like we saw in 2020, I expect the models to correct stronger going into 4-6 in December over the next few weeks. Then the models will be playing catch up with the milder pattern over the next few weeks and especially during the first week of December due to the lag between the MJO convection and the eventual 500mb response. Also note the record SSTs near the Maritime Continent with the -IOD which could stall the MJO in 4-6 well into December beyond what the current weekly forecasts are showing.

 

GEFS stronger with MJO 4-6 VP anomalies in early December

 

 

0z run of the Cfs2 weeklies shows a cooler 2-3 weeks than previous runs, but then starts to warm toward the end of the month of December. The Cfs2 is definitely on board with a strong pass thru the warm phases and has been for days, so I  assume it represents your thinking.

https://www.tropicaltidbits.com/analysis/models/?model=cfs-avg&region=us&pkg=T2maMean&runtime=2024111500&fh=504

But the monthly forecast shows a normal to BN temps in the MA & NE for January. My guess is it holds a fairly strong wave into the cooler phases to support the cooler January. 

[Typhoon Tip]

2 hours ago, bluewave said:

The EPS tends to be too weak with its MJO amplitude near the end of the effective 15 day forecast period when going into phase 4-6 like it’s showing in early December. So if we look at the VP anomalies charts they are all showing this current MJO in the IO progressing to the Maritime Continent in December but the GEFS is stronger. If there isn’t to be some type of mismatch like we saw in 2020, I expect the models to correct stronger going into 4-6 in December over the next few weeks. Then the models will be playing catch up with the milder pattern over the next few weeks and especially during the first week of December due to the lag between the MJO convection and the eventual 500mb response. Also note the record SSTs near the Maritime Continent with the -IOD which could stall the MJO in 4-6 well into December beyond what the current weekly forecasts are showing.

 

GEFS stronger with MJO 4-6 VP anomalies in early December

 

 

are we looking at mjo or we looking at a result of the walker circulation -

for the gen reader, mjo doesn't present much more than 20 deg of lat n/s of the equator.  it's the wave dispersion kinematics, spread out over the larger manifold beyond that latitude range, down stream ... which means by that physical definition, it is indirectly modulating as a forcer. 

it's also high subjected to constructive versus destructive wave interference in the rossby scale.   that's why some mjo phases appear to correlate to pattern ( lag ), where other do not ..despite similar magnitudes.  also, we bear in mind that the mjo can straddle one side of the equator more so than the other.  some stronger wave/rmm prognostics could in fact be registered in the southern/northern side, respectively.

there's a lot to consider there in the total machinery of the mjo ... and that look on those panels there appear to reflect more of the in situ walker signal.