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I am wondering @Bob Chill if this event here is not one of a couple that helps to create the NAO block. Crazy, double the rate, of intensification going on here. A super Bomb !

Sometimes, as Bob states, the - NAO simply arrives unexpectedly. Although, the Euro Control did have a solution a few days back showing a stout Davis Straits block, maybe even earlier than that. Hopefully, it becomes a reality and raises the potential of a more significant storm, very cold and longer duration, and even a HA event as previously mentioned. MJO phase 8 seems to support a -NAO, but I believe we will not be into phase 8 until early Feb, ( depending on the model you choose ) So, assuming this NAO block is brought about by Atlantic cyclonic wave breaking and deep ULL passages. If so , does the block last longer than the transient blocks so far this season ? I mention that possibility because the progressing MJO to phase 8 could end support for a longer lasting NAO block.

I love the look, and totally agree with the potential . From Eric Webb , courtesy 33, Here is Eric's post: < As you'd expect for a central Pacific MJO event coupled w/ a NINO leaning base state, the LR GEFS has a very active southern stream and is wet in the southern US and along the eastern seaboard.

Putting down bets for some sort of HA event ........ after day 10.

Nice loop -

For those who worried Canada would be scoured of cold I just looked and knew it was going to be cold up there, but some of these numbers and the expanse of the arctic air is remarkable. So, there is your cold air source for down the road. https://www.timescolonist.com/strong-winds-snow-on-b-c-s-south-coast-snow-deep-freeze-in-the-north-1.24049987

And, as as Don stated yesterday, that higher amplified state in 7 increases the odds of snowfall in the East towards the end of Jan. bluewave, any thoughts on the developing NAO domain block we are seeing in the GFS and the Euro ? Do you believe it will indeed be transient in nature and then giving way to the more pronounced - EPO ? I know Isotherm thought if we were going to get any significant pv disruptions and a -NAO it would be later in the winter. Wondering the implications for Feb and even March and what happens too with the NAM state.

Bob, do you recall what happened in our area last Jan from the 21 st to the 30 th ? bluewave was mentioning just moments ago the pattern portrayed below is a very close match to last year during that time period.

Agree, I am hoping we do get some undercutting events and a period or two of an active STJ. Extreme cold not needed, as many here have stated the last several days. Rather have multiple storm chances, to score in at least a couple. Some MJO phases I believe further down the road may support a -NAO and I do favor later in the season for a Davis Straits block.

Ha ha ....... you underestimate your effect on the weenies. disclaimer ....."some weenies " On a side note, come to papa baby / and the CFS has done a good job as well with the MJO progression and trends.

In the OLD days a combo of the Eta and the Euro both forecasting snow in the short to medium range was a lock , maybe these days a combo of the GFS and the Euro is a confidence builder in the medium range. I mean eventually all this clear moisture has to turn white

I place little faith in this snowfall prediction, except to say, the more extensive the area and the further South it extends certainly raises my confidence level for later in the month and it has support from the Euro. So there

Not as much an issue in a moderate or a strong Nino, as you know, when you see a huge moisture laden storm systems approach from the SW. Then we snow at 12 degrees. We have had an active STJ this season so far, so that is a plus. As for the SE ridge, maybe it will not get displaced as much as some think. All I can say is that we have potential, it is never easy.

There is a pattern that makes this outcome more likely. When there is little blocking ( we lose confluence, 50/50, pv location, etc and also taking into account the trough axis location ) you can actually have repeated episodes of very cold and then transition to warmer/mild and wet. Happened many times last year in the winter and so far this year when storms have cut. Granted you might go the route of snow>ice to rain as well if there is CAD set-up and if the air mass is very cold. You might also get re-development in cases such as the primary weakening to our NW, and then a new center develops closer to the coast, but with out latitude the moisture usually ends before the real cold moves in and we can transition back to all snow. Areas to our NE benefit the most.

Don S update from a few minutes ago in the NYC forum. I like it ! <<< Quick pattern evolution thoughts... The base case as per historical data has been that the MJO would progress into Phases 7 and then 8. More of the guidance is showing a move into Phase 7 in the extended range. The GEFS and bias-corrected GEFS show the MJO moving into Phase 7 at an amplitude > 2.000. Passage of the MJO into and through Phase 7 and very high amplitudes during the second half of January have typically seen trough development in the East and a snowy February. These developments suggest that the potential for a pattern change away from the much above normal warmth (with short breaks) for the first half of January are increasing for the second half of the month. The closing week has the potential to see the onset of a sustained colder pattern. >>>

Another thing to keep in mind is whether we get a surprise transient NAO block as previously it was in a couple Euro Control runs.

Here is an IOD update. Keep in mind the influence continues from this record setting event and it is still a pattern driver to a degree, but is gradually losing its effect.

As others have mentioned here regarding the MJO, overall change to colder might have legs into Feb .

Most interested what happens after the cutter, near the 21 st to 24 th time period.

Brilliant, because too many times in the past we have had the rug pulled form under us. Also, I am in it for a sustainable period of cold, along with snow as well please. Too many transient cold periods, I hope we lock into a longer period of cold and storm potential.

@bluewave simply in terms of modeling do you have stats or a personal favorite when it comes to predicting the MJO. What model tends to do best? As, I know there are many.

Good post, and you might enjoy this read I brought from Tip over in the NE forum regarding the coming - EPO .... see bold section From Tip : < Not sure who's said what over the last page or so ... so all credit where it is due, but the 00z GFS operational run ( and few priors that I can recall ) have been more aggressive with -EPO than it's ensemble means, but now the mean "might" be catching on just looking at the individual GEF members. As rumor has it the EPS has been showing changes in the Pacific in the extended for a few days now.. . The 00z Euro is hitting at a middling robust blocking ridge over Alaska. Given that these more sophisticated operational versions of disparate model types are nodding over that index switching modes, these are not altogether bad operational indicators for cold. I'm interested in ESRL's EPO progs from 00z because just eye-balling the GEF members individually, it does appear to be more of them situated blocking nodes and or ridge axis at higher latitudes of N-NE Pacific arc. The take away there/mean is that they actually have it, not so much any given particulars that are unlikely to be correct. We'll cross the orientation bridge when the time comes. But, from D4.5 right out to the end of the D13 ..that entire period is now rather robustly -EPO in the operational 00z, and 06z GFS, so those rumors of the EPS Pacific are not 'entirely' alone. In the dailies, the GFS has been signaling a whopper cold whack out there around ( now ) 204 or so hours.. but total smear time is probably a 3.5 day stint at < 520 dm thickness.. with some nadir temps that are dropping steam plumes. Yet the robuster ridge(ings) over the Alaskan sector are still out there in the la-la range of that model. I like it when 564 dm centers over Fairbanks! There's likely to be a few renditions of mass loading into the Canadian shield, with on and off disturbance orientations/existence but, the dearth of bona fide winter patterning is apparently on a shortened lease here. >

Of note, the GFS has the Jan 22 threat, and while taking a quick look this morning the Euro Control has a snow event for the Eastern areas for Jan 20th . There is potential between Jan 20 th and the 24 th. and probably beyond as well. At least the option to track versus getting a tan. Also, some indications we may be trending to a + PNA look way out in fantasy land.

Will be interesting to track the continued changes moving forward.

It appears now that the TPV takes up home on our side, maybe in the vicinity of Hudson Bay. So, a readily available cold air source. Maybe this potential set-up creates a more conducive environment regarding the NAM state , as mentioned previously, anything closer to neutral would be a lot better than right now. I will ride any improvements in AO and the PNA states, would love to get some favorable indices later in the month. If we do, that in itself will lend a lot more confidence that we can track a legitimate threat for the coastal areas, my area and your area included. psu already got his 5 inches