EasternLI

00z href fram was gross. Stay safe out there. 

Truth be told, I would welcome a warm 2nd half. Just not a lot of confidence yet how that timeframe shakes out. Need to wait it out a bit longer. 

6 minutes ago, snowman19 said:

Severely positive NAM/++NAO, ++AO, there will be nothing to stop a SE ridge pump

That's cool. You already put away the winter attire. Nothing to worry about then.

14 minutes ago, EastonSN+ said:

That week 2 forecast does indeed look like a "torch".

I guess impossible to forecast if that is static or a temporary 1 to 2 week "flip".

Not necessarily. That's tropical stuff not 500mb anomalies. Have to be careful there. Especially later in the period. Tropical convection is the most complicated parameter on modeling. Best to just monitor trends. I wouldn't read too much into those RMM charts right now either. If we're dealing with competing areas of forcing. 

3 minutes ago, bluewave said:

That’s a great example of the split forcing pattern. The forcing near the dateline and WPAC is driving that ridge off the West Coast. While the IO convection is trying to pull the trough back from the East Coast. So the model comes to a compromise between the multiple areas of tropical convection.

 

Yeah, was just looking through that stuff from 00z. That's exactly what it looks like. Something like that. Will have to keep an eye on that. 

2 minutes ago, EastonSN+ said:

Thanks the GEPS looks similar but a wider trough (possibly due to member spread).

Hate to ask but was the EPS similar?

Some similarities. Remember too that the others go out just a little bit further. Have to keep an eye on that TPV and where it goes beyond this. Something to look for on future runs. 

Beyond mid month is still questionable. I personally wouldn't feel good about any solution until we have decent agreement between eps and gefs. Going to have to watch that TPV and what that does too.

WAG but the 14-16th period looks interesting. Based on the big picture view. With a TPV lobe pulling out and some sort of transient PNA spike. 

1 minute ago, EastonSN+ said:

Thanks, it actually starts to move towards GEPS at the end with the East Coast ridge.

Obviously cannot tell if it's a temporary reload or the change that the Mets are alluding to. 

It's signaling a retrograde towards the very end. Seems due to some increased phase 2 activity from the looks of the tropical stuff. That can be a storm signal too. Gotta watch that. There could be something lurking out there before then like brooklynwx99 is saying. Afterwards, It's heading in this direction gradually I think. At least on today's edition. 

13 minutes ago, EastonSN+ said:

Anyone have the 12z eps hour 360?

 

Here's the 10-15 loop.

49 minutes ago, EastonSN+ said:

Thanks!

I find it interesting that Jan and Feb the MJO we're in warm phases before March.

Here's a great illustration of what happened in 2015. Versus what occurred in December of this season. In a single image from the following paper. But it's also important to keep in mind other factors which may be present. One such example could be the PDO. Which was positive in 2015. Or the QBO. Nothing works in a vacuum. It's all interconnected. That's also important. It can get really extremely complicated. That's what makes seasonal forecasting so very difficult to this day. This image shows what effects could be expected from 2 different areas of focus via tropical convection. You can see how different the effects can be just from some subtle difference in location. Because of the rossby waves originating from these events. Indonesian activity drives a -PNA. Which we witnessed in December, in an anomalous way. However, move that just a bit east into the west/central Pacific. You see something like a 2015. Which is what happened that season. Hope this can be somewhat helpful. This is why we look to the MJO for clues. 

https://www.nature.com/articles/s41598-019-49449-7

2 minutes ago, bluewave said:

Yeah, we were all waiting on the MJO back in December. But it got stuck in the warm phases longer than forecast due to the record warm pool north of Australia. The magnitude of the shift in January matches some recent years like 14-15 and 15-16. But those were El Niño years which we came to expect dramatic changes after a warm start. This is really the first time a La Niña shifted so much from December record warmth and lack of snow to record snow and colder in January. Now we have an example of this NE PAC blocking pattern during ENSO neutral 14-15, El Niño 14-15, and La Niña in 21-22. So it can occur in varying ENSO  states. This makes seasonal forecasting more challenging since this mode can replace or enhance ENSO expectations. 
 

 

 

Agreed 100%. It's proving beneficial to look at things from a broader perspective. Instead of focusing very heavily on ENSO SSTs alone. Which has been the go to main method for many years. It's helpful to look a little more closely and keep an open mind in recent years. Older analogs have become less useful, which has been discussed. Keeping track of those marine heatwaves is going to be important moving forward. 

7 minutes ago, bluewave said:

Recent studies have found that the persistent ridge near the West Coast  and  Hudson Bay TPV pattern is a result of rising WPAC SSTs.

https://www.mdpi.com/2073-4433/10/12/793/htm

4. Conclusions

The diagnostics undertaken here suggest that the leading mode of the wintertime atmospheric stationary waves in the Northern Hemisphere has undergone a notable change. Since the 1980s, the first leading mode of anomalous winter stationary eddies in the subseasonal timescale has alternated from the PNA to a comparably strong NAWD. Given that EOF describes the variance of individual patterns, the observed increase in the amplitude of NAWD suggests that it may have overtaken the PNA as the more common type of winter variability, with increased influence from western North Pacific SSTs. The CESM large-ensemble simulations forced with increasing greenhouse gas indicate that the NAWD variance will gradually amplify alongside its low-frequency natural variability. This result implies that the subseasonal variation of the atmospheric circulations over North America could continue to be dominated by the NAWD mode, with the potential to sharpen the east–west temperature and precipitation division across North America.

Further comparison of EOF1/EOF2 with PNA/NAWD using spatial correlation reveals a pattern change that is consistent among different reanalysis datasets. Analysis of the paleoclimate simulations suggests that NAWD does co-vary with the global temperature variation at centennial timescales: the NAWD variance was weak in the cooler Pleistocene and gradually increased and stabilized in the warmer Holocene. We further examined large-scale forcing of both atmospheric and oceanic origins for the amplified NAWD and found that most of the documented climate indices, which showed a connection to the 2013–2014 extreme winter of North America, are insignificantly correlated with NAWD with the exception of certain oceanic features like the WNP and Niño 4 (Y + 1); these imply that regional SST anomalies in the subtropical West Pacific may provoke teleconnections that affect NAWD. Future examination of the dynamic processes leading to the NAWD amplification should consider the stationary waves maintenance, namely the jet–terrain interactions, tropical and extratropical diabatic heating, and the effect of Arctic amplification.

 

 

 

I must admit. This is all sort of why I saw this season as potentially pretty interesting back in late November. With the MJO possibility initiating the mixing up the pattern. Just not to this degree we appear to be witnessing. I'm very pleased to see these thoughts working out better than expected. It's an incredible flip from the December mess. Nice paper too, a rather fascinating season continues.

4 minutes ago, EastonSN+ said:

I know it's only op runs, but they were kind of ugly WRT snowfall chances.

Not concerned. You set up something like that. Something will pop up I'd think at some point. It's a far cry from what we were thinking not very long ago. February is not canceled this year. 

This is what looks to set in. Starting ~day 9 until the foreseeable. There's good ensemble agreement for this now. 

Good stuff. You can thank the MJO for initiating the process IMO. 

23 minutes ago, bluewave said:

Yeah, competing marine heatwaves are becoming the key to understanding these extreme winter patterns. It adds a new level of complexity to seasonal forecasting. So the old La Niña or El Nino based forecasts are becoming less reliable. 

Absolutely. It's the same thing we observed in December, but now it's a bit different.

8 hours ago, bluewave said:

We are already seeing a model disagreement between the GEFS and the other guidance near the end of the ensemble runs on February 16th. The EPS and GEPS keep the +PNA pattern going. It could be related to the split forcing in the tropics. The convection south of India would normally produce a -PNA in February. But we see the lingering forcing near the Central Pacific which is more Nino-like as was the case in January. Forcing in that area favors a more +PNA in February. So that may be what the EPS and GEPS is picking up on.

 

 

Yeah, it's a great point. I was thinking about this a little. Kind of goes along with the ideas of patterns lingering in recent years. But also, check out the 2 areas of tropical convection there. Compared to the actual (not anomalies) sst. It lines up really well with the warmest water. But the cooler water near Indonesia is playing a role to it appears. That's interesting.

10 minutes ago, MJO812 said:

It might not be done correcting south

Yay, more ice...

That's a concerning euro run given what the gfs is showing. 

Good grief if the 12z gefs comes to fruition with these looks. This is prime for some arctic intrusions. Starting sooner rather than later.

I'd imagine some sort of middle ground between euro and GFS would be realistic. But this bears watching for parts of this forum. With temps crashing and what looks to be a pretty cold Saturday following. Losing power would not be the best situation. 

3 minutes ago, mikem81 said:

The NAM has wild swings after HR 48 (as we saw big time last weekend). Wouldn't look at it until tomorrow 12Z plus its always overamped after hour 60. Stick to EURO/CMC/GFS blend and look at trends today

Well yeah, not taking it to the bank. Just posting it. I'm more interested to see if the gfs holds onto it's idea with this. And which way the euro leans at 12z more than any other guidance right now. 

This is the wrong trend direction Nam. Go the other way. 

3 minutes ago, EastonSN+ said:

Speaking of the LR, I love this look for February

Neg EPO supplying the cold. Just enough SE ridge to avoid suppression.

To me I see a warmer 1994 here.

Also, I truly believe the Negative NAO hurt us in December as it created compression between the SE Ridge and the -NAO. This look of course would induce cutter risk, however with cutters you get bootleg blocking AND introduce weak trailing wave opportunities. I believe we would have had more snow with a positive NAO in December.

Finally, and I will admit I do not fully understand this, but we will have shorter wavelengths in second half of February. I am thinking this would mute the effects of a deep RNA.

 

00z EPS for comparison. To me, these looks suggest risks of some arctic shots. With a ridge position like that. Plus the vortex biased towards the eastern half of Canada. Maybe some kind of split flow look? Don't just look at the colors. Check out the height lines as well. It looks as though there would be cold air dumping east of the rockies with these looks. This is different than December in that the ridge is much closer to the west coast instead of further west by the Aleutians.