leo2000

Brutally cold and snowy winter on the way. I know Don was mentioning about the cold pool is much smaller than in 1968 but this is not arctic air coming it is Siberian cold and with the pdo rising that would increase snowstorm chances.

Different answer on Google search ai answer says as few days to a couple of weeks for a major SSW to be felt in the mid latitudes such as North America and eastern Canada. With the effects potentially lasting up to two months. Regardless, there comes a risk with this as we could end up getting a suppressed storm track depends on where the SPV sets up right over Hudson Bay is ideal.

The models are simply overdoing the warmth expect more cold dominating over the warmth.

Showing a fantasy storm for Nova Scotia already in the long range a good sign. Gfs 18z at 360 hours lol.

The best you can ask for really its going to happen for sure now.

Some of the operational runs bring it more out east. We will have to see.

I got this from Grace over in wx sphere she seems pretty knowledgeable about the weather. Of course the Pacific is the driver it can make make or break Winter. I would not worry though we are going to have a strong negative EPO and a positive Pna or negative Pna.

Yes, nothing awful about MJO phase 6 in December so of course phase 7 would be even better. Phase 6, La Nina DEC

February may not be a lost month this winter either.

The Climate Prediction Center is also showing what the Euro Weeklies is showing with the cold air and above precip and a SE ridge down to the south.

I heard from here the cold air will bleed east. Question is, is this a Siberian event? or North Atlantic event type SSW. As the Siberian event lasts longer the models seem to indicate that it's an Siberian event. I am rather confuse though as the EPS model went from 81 percent predicting a major SSW down to 56 percent last night. This is from Ben Noll on X. @BenNollWeather A sudden stratospheric warming event is forecast to peak around Nov. 25. This will probably disrupt the polar vortex, with Arctic air initially plunging into the west-central United States during late November, accentuating the stormy weather pattern headed for this region. https://x.com/i/status/1989324943415234596 Just two months after a rare stratospheric warming event disrupted the polar vortex above Antarctica, one is poised to do the same above the Arctic before the end of November. Watch the Southern Hemisphere's vortex go from perfectly round to ragged. https://x.com/i/status/1989347337932607567

Yes we don't want to get too cold suppression depression happens then. We also don't want the shreddar pattern either like we had last year. An interesting video from Met DT about December.

Getting a better Pacific as we head into December can't have both a good Atlantic and Pacific have to lose one rather lose the Atlantic anytime over the Pacific anyday. Still a decent atlantic too though it seems.

Wow indeed 82 percent now!!! This is from Allan Huffman on Twitter he says: Today's 12z op ECMWF and EPS mean both show the 10mb U wind turning negative, meaning a change to an easterly wind direction over the polar regions and an #SSWE with 41 of 50 EPS members (82%) showing this reversal with 11/25 the day with the most negative members. Sudden Stratospheric Warming Events, can weaken the tropospheric polar vortex, allowing for increased high latitude blocking (-AO) and the enhanced risk for arctic air discharge into the mid-latitudes (North America, Europe, East Asia). A late November SSWE is relatively rare, and COULD help favor a cold start to meteorological winter(December). The last November SSWE was in 1968.

I think that's unlikely based on what happened last Christmas I can see it being similar. Plus, I think we are going to an early SSW locked in for size weeks starting around first week of December last into mid January then the annual January thaw the pv reconsolidating and the some weaker again of the pv allowing for stretching of the pv but no more SSW but will allow winter cold and snow to return.

The only way for that to happen I think is through a positive PDO/positive TNH pattern.

To Bluewave- A negative IOD apparently can change the pattern, the eastern USA may see an increase in snowfall or precipitation, as the combined effects of a negative IOD and La Nina can enhance atmospheric moisture and create favorable storm tracks. To Snowman- While the blob is cooling its such a large blob and the longer it's out there the more the impacts will be felt across the northeast USA and eastern Canada with plenty of cold and snow.

Yeah but that is an historical marine heatwave in the north Pacific. Sure yes doesn't look like it will bring a prolonged +TNH but with the forecast being neutral enso for the second part of winter it's a toss up.

The big reason why I am optimistic about this upcoming winter is the north Pacific warm blob. The last time this happened back in in 2013 we all know what followed.

I ain't following all this La Nina non sense about it being moderate. This is a neutral enso winter not La Nina or El Nino. https://wmo.int/news/media-centre/la-nina-may-develop-it-likely-be-weak-and-short-lived

Just keep the MJO in the circle as all its wants to do is go into phase 6.

Not the kind of news I would like to hear. The GEFS has been doing very well with the MJO sadly. But there is a caveat perhaps we get a big displacement of the TPV that would overwhelmed the MJO signal. Oh i forgot to add ensembles and Euro Weeklies are showing the colder pattern returning early to mid January. The pattern that came in early December muted the MJO signal when it was in phase 6 will probably again. I think when the colder pattern comes back this time it could come back for much longer than last time and with abundant moisture.

I was seeing that as well. But looks like the PV will not consolidate as it will break up once again in two pieces. https://www.tropicaltidbits.com/analysis/models/?model=gfs-ens&region=nhem&pkg=z500a&runtime=2024121512&fh=354. I go with the GEFS on this as the EPS is not good with the PV and the MJO. The GEPS showing the same thing as the GEFS. https://www.tropicaltidbits.com/analysis/models/?model=gem-ens&region=nhem&pkg=z500a&runtime=2024121512&fh=348

The thing is the GEFS has been more right about the MJO progression then the EPS has. Just look at what the 12z GEFS is showing at the end. https://www.tropicaltidbits.com/analysis/models/?model=gfs-ens&region=namer&pkg=z500a&runtime=2024121212&fh=384

Depends in a La Nina Background state MJO phaase 6 is cold in the east.