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Pattern Freezing Ferocious February

GaWx said:
1. The last 15 very strong MJO events (going back to 1988) have been either near normal or warmer in the SE US. If you specifically look at those that included phase 7, they have averaged even warmer. I think my dataset size is decent enough to give the general idea that a very strong phase 7 doesn't by itself favor a cold SE. Can it still end up cold this time even if it were to end up very strong? Of course it can based on other factors like +PNA and -AO and it may end up cold. But my study says a very strong phase 7 by itself doesn't specifically say it is likely going to get cold in the SE. I think JB and others are misinformed in thinking a very strong MJO by itself screams cold down here.

2. All of my research is based on RMM data due to there being 42 years of readily available data and because we're talking about a projected very strong MJO (4) on the GEFS and still strong (2.5) on the EPS on the RMM (I.e., apples to apples). I still by the way am forecasting it will come in
much closer to the EPS' 2.5 based on GEFS strong tendency to oversimplify. So, that actually may help some for the SE since it wouldn't actually be "very strong" but instead just "strong".

3. I use ATL/SE US because that's what I'm addressing since that's where we live and we want to know how the very strong MJO tends to influence our wx, not Joe Blo in Chicago or NYC. That's what makes the SE "special". And I don't see a statistical credibility issue with just examining the SE US.

4. Possible physical reason per MDA pro mets: very strong MJO favors more warmth from
the tropics lessening Arctic influence.

5. I just talked to MDA met. He agrees totally with my analysis as well as my prediction that the phase 7 peak will be much closer to the EPS' 2.5 than the GEFS' 4.0 due to bias of GEFS way overdoing past MJOs. He also said the projection by the Euro suite is for the MJO to be weak once it gets to phases 8-1-2, which would then favor colder in the SE. That I agree with. So, if the +PNA, -AO, weak MJO phases 8-1-2 were to then coexist, it would then favor a cold SE mid February. Phil has been ontonthis idea. In essence, I think the cold may end up delayed but not denied in the SE. I mainly think that folks are expecting it to occur too soon.
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Here's the link to the Kim et al study that outlines the EPS's dampening bias with the MJO when it's initialized in the Maritime Continent (again likely related to its convective parameterization, the KF scheme in the GFS likely aids in its propagation through this region). Reliance on one particular model over the other is often situationally dependent even if said model (the EPS) is more accurate than the GFS. For example you probably wouldn't rely on the Euro over other NWP to predict the evolution of shortwaves in the southwestern US for example because it oversimplifies (& the thus slows them down relative to reality) and it's gravity wave drag parameterization forces the model to incessantly depict a planetary wave configuration that interferes with the background waves because it's orographic forcing is too weak and this is still apparently a problem in the model to this day. This leads to the model overamplifying troughs near the Rockies in the winter when the jet is strong
https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-13-00480.1
 
Jon said:
My confidence level is around 90%.
For one it hasn’t been delayed, it’s always been Feb 3-5 onward.

I’d admit at h5 it doesn’t look pretty, yet (it will), but a few things to keep in mind:
1. We don’t live at 500mb, thankfully
2. Models and ensembles usually have a very tough time with PV drops. In fact, many of the past PV drops kind of “snuck up” on us to the point where I remember back in 2013(?) I believe, where raleigh got down to the single digits, that PV drop showed up on a control run. Also, it’s incredibly hard for a statistical model to translate stratosphere to lower levels his dad out.

At least now we have the advantage of knowing it’s not going to sneak up on us, and we have a number of factors helping argue for cold as mentioned in this thread (MJO, -EPO off the charts, Climo favored month, Displacement/splitting of the PV in the stratosphere consistently modeled)

It’s ok not the trust Op models. They’re guidance and not gospel. A day ago there were 100 new posts just out of full fledged excitement. Now hardly any - and I can promise it’s due to watching operational runs and forgetting the “big picture”

Let’s take a look at the 24 hour GFS ensemble trend (5 day mean) for Feb 4-9:

5822aa64577729e4df1444a74ba5d4f9.jpg


To some the “cupping” ridge over the southern US is an eye sore, but really it’s par for the course when a large anomalous PV drops down to Hudson Bay. The models have to compensate and put ridging somewhere, especially when it’s this far out.

As you can see in the first image we had a positively tilted trough in the west, gross- but:

You can see the changes here just in 24 hours. We need the SER giving us issues to move to the Atlantic, to essentially bridge the two troughs, one over Hudson Bay (our PV) the other towards Scandinavia. This would give the ridging out west no choice but to move more east, and again the PV will adjust slightly more east, setting up shop for deep cold over the central and eastern US.
9cc462797c2f6d7d7e805a0a6777a957.jpg
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Great perspective Jon - I really enjoy your posts. Many thanks!
 
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Man that's a huge winter storm for the Ohio valley late next week on the 12z gfs if taken literally.

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Clayton Reid said:
Except the delay in cold may be wasted unless you know of some decent storms in Late February and early March that aren't just marginal and are very cold or cold afterwards with it being very warm or warm in early February through mid February. Cold being delayed won't help us with a good winter storm is what I'm afraid of unless you can prove me wrong. And please don't use very rare unlikely events like the 93 superstorm
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I think you should create your own whining thread and get your posts out of this one where actual discussion is going on.
 
That energy in the West could make for a fun day 9 / 10 storm this run

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Bill McMillan from Indywx.com is calling for 15-20" of snow between Feb 1 and March 6 in Central Indiana so if thats the case i would think that would bode well for the southeast in terms of cold and snow chances esp in mid to late Feb.
 
SoutheastRidge said:
Bill McMillan from Indywx.com is calling for 15-20" of snow between Feb 1 and March 6 in Central Indiana so if thats the case i would think that would bode well for the southeast in terms of cold and snow chances esp in mid to late Feb.
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Their snow accumulations seem to have a late start this winter. It's been snow dry in the OH valley.
 
weatherfide said:
Their snow accumulations seem to have a late start this winter. It's been snow dry in the OH valley.
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Its been very dry here in Eastern Indiana. Ive been here for 45 days and its rained once I think. About 10" of snow in that period which isnt that much really. I think February could be exciting for a lot of people in the south and midwest.
 
Arcc said:
I think you should create your own whining thread and get your posts out of this one where actual discussion is going on.
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I am trying to add to the discussion, but I honestly don't see anything that cold or interesting. I keep hearing delayed but not denied, but I just don't want it to be wasted. I mean what happens if you spent all this time discussing freezing February, and it's really not even looking like it'll be freezing or get close to it if we are lucky based on current trends. It's really hard to just ignore the model guidance when they keep screaming ridge, and the GFS has a big cold bias.
 
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