Wintry Winter Discussion 2023/24

[Webberweather53]

It has inched a lot closer towards phase 3, esp near the beginning of that period.

View attachment 140362

The reason for the loop-de-loop/the slowing of the MJO over the Indian Ocean recently has a lot to do with the recent collapse of the positive phase of the Indian Ocean Dipole (+IOD). The IOD has a huge impact on the amount and distribution of convection over the Indian Ocean and Maritime Continent. The positive phase, w/ a cold tongue of upwelled water adjacent to Sumatra, suppresses convection over the eastern Indian Ocean and Maritime Continent.

You can basically think of deep convection like the brakes of the MJO. When the MJO moves through areas of the global tropics that are convectively active, it slows down, whereas the MJO speeds up through areas that have less convection.

The real reasons this connection between convection - MJO phase speed exists actually is quite complicated, and I won’t elaborate further here, but you get the idea.

So in essence, this kind of abrupt basic state change we saw to the IOD (going from positive to neutral) triggered a major change in how the MJO propagated through this part of the globe, in this case, actually slowing it down. It’s not something that’s easy for models to pick up on

 

[Webberweather53]

The Chinese model has it snowing down into Florida ?

 

[Stevo24]

The reason for the loop-de-loop/the slowing of the MJO over the Indian Ocean recently has a lot to do with the recent collapse of the positive phase of the Indian Ocean Dipole (+IOD). The IOD has a huge impact on the amount and distribution of convection over the Indian Ocean and Maritime Continent. The positive phase, w/ a cold tongue of upwelled water adjacent to Sumatra, suppresses convection over the eastern Indian Ocean and Maritime Continent.

You can basically think of deep convection like the brakes of the MJO. When the MJO moves through areas of the global tropics that are convectively active, it slows down, whereas the MJO speeds up through areas that have less convection.

The real reasons this connection between convection - MJO phase speed exists actually is quite complicated, and I won’t elaborate further here, but you get the idea.

So in essence, this kind of abrupt basic state change we saw to the IOD (going from positive to neutral) triggered a major change in how the MJO propagated through this part of the globe, in this case, actually slowing it down. It’s not something that’s easy for models to pick up on

View attachment 140363

In your opinion does it make more sense for the cold to dump way out west, east, or somewhere in between? The models keep flipping back and forth so obviously they are having a hard time with something. But which one is more likely?

 

[rburrel2]

If you really look at the GEFS members almost every one of them has a winter weather threat for our area in the 8-12 day timeframe. A lot of them are ice storms and/or glancing blows from weak systems, not many blockbusters. Not a bad look since it doesn't take much wintery precip to make us happy in the first place.

 

[Chazwin]

The Chinese model has it snowing down into Florida ?

View attachment 140364

If that map were to ever verify, can you imagine the weenie freak outs from the NC foothills up to the Delmarva Peninsula?

 

[Webberweather53]

In your opinion does it make more sense for the cold to dump way out west, east, or somewhere in between? The models keep flipping back and forth so obviously they are having a hard time with something. But which one is more likely?

Cold dumps out west first, probably ends up being a tad slower than forecast to come east vs the GEFS, but it moves east in week 2 regardless.

 

[Snowfan]

 

[Prestige Worldwide]

https://x.com/bigjoebastardi/status/1744443281608499444?s=46&t=j_-aw-4tjFwrt5AoXKNk5A

 

[griteater]

3-run trend (Nov/Dec/Jan) of the UK Met Office GloSea6 for February. Heavier -NAO w/ split flow across N America. In my view, Euro is the best seasonal model with the Stratosphere/AO/NAO, with Met Office 2nd

 

[griteater]

Dec 11 - thoughts on the pattern ahead. I'm switching these to 5-25 day outlooks for the rest of winter (instead of 10-30 day)

 

[griteater]

This would be an excellent way to load cold air into N America prior to / as the Pac Jet extends into an El Niño split flow pattern in early February

 

[Itryatgolf]

This would be an excellent way to load cold air into N America prior to / as the Pac Jet extends into an El Niño split flow pattern in early February

Griteater, I may be asking a dumb question but this time we want to see the pacjet extending, but not much and may allow better opportunities at winter weather?

 

[griteater]

Griteater, I may be asking a dumb question but this time we want to see the pacjet extending, but not much and may allow better opportunities at winter weather?

Generally, you want to see some Pac Jet extension, yes, just not too much. The Pac Jet being retracted back into the W Pacific is what you see with -PNA patterns

 

[Itryatgolf]

Generally, you want to see some Pac Jet extension, yes, just not too much. The Pac Jet being retracted back into the W Pacific is what you see with -PNA patterns

With the warmest waters shifting further west now in pacific, could be rather interesting rest of the winter imo

 

[SD]

This would be an excellent way to load cold air into N America prior to / as the Pac Jet extends into an El Niño split flow pattern in early February

Op gfs is the holy Grail of how we could evolve going forward with the cold waves being dumped in from the AK ridge and the stj undercutting. Reminds me of the Jan Feb 15 evolution but you have to think it's too extreme right now..... right?

 

[griteater]

Op gfs is the holy Grail of how we could evolve going forward with the cold waves being dumped in from the AK ridge and the stj undercutting. Reminds me of the Jan Feb 15 evolution but you have to think it's too extreme right now..... right?

I think the split flow and eventually another round of retrograding GL block are coming in Feb. The pre-load with cold air would be the piece to make it sweet

And remember the low latitude southern stream idea here on the Euro Seasonal for Feb. The stronger the El Nino, typically the farther south the southern stream / STJ. It's just a matter of whether you can load cold air into the pattern

 

[griteater]

Jan 16 - whether warm noses or SE ridges, cold rain or pre-emergent applications, we forge ahead.

 

[SASQUATCH]

Jan 16 - whether warm noses or SE ridges, cold rain or pre-emergent applications, we forge ahead.

Could someone copy and past this image? For some reason I can never see grit's images at work in the current format, thanks in advance.

 

[Itryatgolf]

Jan 16 - whether warm noses or SE ridges, cold rain or pre-emergent applications, we forge ahead.

I'm curious if we get that CW again end of this month, would that extend the cold into February? Backloaded is usually the them in niños I thought. A jet extension would delay a cold pattern from developing. Hoping we get into colder phases again in Feb to have a solid few weeks of colder stormier weather

 

[griteater]

Could someone copy and past this image? For some reason I can never see grit's images at work in the current format, thanks in advance.

I tried it via attachment here below (instead of image service). That work?

Also can see it here: https://x.com/griteater/status/1747307483612209442?s=20