Absolute Vorticity

Bgoney wrote: ↑Fri Oct 20, 2023 3:18 pm Also saw where NOAA dusted off their generic El Niño winter prediction maps



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Bgoney wrote: ↑Mon Oct 23, 2023 8:13 pm CFS extends the stagnant pattern in the equatorial pacific well into the second half of NOV



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tron777 wrote: ↑Thu Oct 26, 2023 9:04 am The deeply -PDO should be no more this winter. I am expecting it to be in that weakly negative to neutral range instead of -2 like it was earlier. I believe that should help with more +PNA episodes this winter instead of a raging -PNA as we have been seeing thanks to La Nina. All in all though it is going to come down to the Arctic domain. If the blocking is there, this winter should be a good one. If it isn't, then it will no doubt be mild and probably wet too. We shall see! So far the blocking has been there and quite a bit too in 2023. Hopefully it continues. PV right now seems weak and elongated but it is just starting to develop and get its act together so the strength of the PV of course remains to be seen. I would assume a weak PV this year is on tap thanks to the descending QBO.

Bgoney wrote: ↑Thu Oct 26, 2023 9:42 am

tron777 wrote: ↑Thu Oct 26, 2023 9:04 am The deeply -PDO should be no more this winter. I am expecting it to be in that weakly negative to neutral range instead of -2 like it was earlier. I believe that should help with more +PNA episodes this winter instead of a raging -PNA as we have been seeing thanks to La Nina. All in all though it is going to come down to the Arctic domain. If the blocking is there, this winter should be a good one. If it isn't, then it will no doubt be mild and probably wet too. We shall see! So far the blocking has been there and quite a bit too in 2023. Hopefully it continues. PV right now seems weak and elongated but it is just starting to develop and get its act together so the strength of the PV of course remains to be seen. I would assume a weak PV this year is on tap thanks to the descending QBO.

Yep on everything, particularly like the QBO status for the winter months.


Probably for a November thread , but after our cold spell the first week of November, ensembles are showing a west pac jet extension into the NW resulting in zonal flow and a fairly big warmup for all the lower 48 and a wet look for the western mountains

tron777 wrote: ↑Thu Oct 26, 2023 10:28 am

Bgoney wrote: ↑Thu Oct 26, 2023 9:42 am

tron777 wrote: ↑Thu Oct 26, 2023 9:04 am The deeply -PDO should be no more this winter. I am expecting it to be in that weakly negative to neutral range instead of -2 like it was earlier. I believe that should help with more +PNA episodes this winter instead of a raging -PNA as we have been seeing thanks to La Nina. All in all though it is going to come down to the Arctic domain. If the blocking is there, this winter should be a good one. If it isn't, then it will no doubt be mild and probably wet too. We shall see! So far the blocking has been there and quite a bit too in 2023. Hopefully it continues. PV right now seems weak and elongated but it is just starting to develop and get its act together so the strength of the PV of course remains to be seen. I would assume a weak PV this year is on tap thanks to the descending QBO.

Yep on everything, particularly like the QBO status for the winter months.


Probably for a November thread , but after our cold spell the first week of November, ensembles are showing a west pac jet extension into the NW resulting in zonal flow and a fairly big warmup for all the lower 48 and a wet look for the western mountains

Definitely agree on a warm up. Then the question becomes do the tropics get involved to force another cool down or do we continue the warmth for a while? That issue remains to be seen.

tpweather wrote: ↑Thu Oct 26, 2023 3:56 pm

tron777 wrote: ↑Thu Oct 26, 2023 10:28 am

Bgoney wrote: ↑Thu Oct 26, 2023 9:42 am

tron777 wrote: ↑Thu Oct 26, 2023 9:04 am The deeply -PDO should be no more this winter. I am expecting it to be in that weakly negative to neutral range instead of -2 like it was earlier. I believe that should help with more +PNA episodes this winter instead of a raging -PNA as we have been seeing thanks to La Nina. All in all though it is going to come down to the Arctic domain. If the blocking is there, this winter should be a good one. If it isn't, then it will no doubt be mild and probably wet too. We shall see! So far the blocking has been there and quite a bit too in 2023. Hopefully it continues. PV right now seems weak and elongated but it is just starting to develop and get its act together so the strength of the PV of course remains to be seen. I would assume a weak PV this year is on tap thanks to the descending QBO.

Yep on everything, particularly like the QBO status for the winter months.


Probably for a November thread , but after our cold spell the first week of November, ensembles are showing a west pac jet extension into the NW resulting in zonal flow and a fairly big warmup for all the lower 48 and a wet look for the western mountains

Definitely agree on a warm up. Then the question becomes do the tropics get involved to force another cool down or do we continue the warmth for a while? That issue remains to be seen.

I agree about the warm up and that is normal for November. Getting snow in mountains and northern plains is nice during November. The one thing throwing me off is the possible tropical system in the second week of November. Has been a strange year imo but the waters are no doubt very warm so a development of a tropical system is possible but just not sure how far north it can really go. Hopefully it at least throws more moisture northward. I always mentioned I will not throw out a winter forecast but each year I can't help myself lol. I do have some thoughts and will always try to throw them out by mid-November. Les I have not forgot about the contest and that item will be thrown out on Halloween.

tron777 wrote: ↑Thu Oct 26, 2023 4:45 pm Well folks... pet the chart below, it appears that for the month of October, Nino 3.4 is only going to avg around 1.6 degrees C above normal. Guess what the Euro had? +2.03 LOL! A huge bust from the Euro and all models really.


Nino 34.png


There is still a chance that this Nino can strengthen a tad like Nov of 1972. It did get over +2 for Super Nino status. But that year October was at +1.8 which is well above where we are right now. So I still say a super Nino is off the table. Moderate to perhaps low end strong is my call which impacts wise won't be much of a difference anyway.

tpweather wrote: ↑Fri Oct 27, 2023 4:16 pm

tron777 wrote: ↑Thu Oct 26, 2023 4:45 pm Well folks... pet the chart below, it appears that for the month of October, Nino 3.4 is only going to avg around 1.6 degrees C above normal. Guess what the Euro had? +2.03 LOL! A huge bust from the Euro and all models really.


Nino 34.png


There is still a chance that this Nino can strengthen a tad like Nov of 1972. It did get over +2 for Super Nino status. But that year October was at +1.8 which is well above where we are right now. So I still say a super Nino is off the table. Moderate to perhaps low end strong is my call which impacts wise won't be much of a difference anyway.

Great Post Les. Never expected a strong El Nino and really moderate is pushing it for the entire winter. Sure you can have one month at moderate status but the remaining months could end up low end. Time will tell and the models have busted on this since last winter as it started out quickly but has steadied since then . I am still looking at what happens when we have 3 La Nina's followed by an El Nino. Those are interesting but again things have changed since these occurred so more info to factor in.

tron777 wrote: ↑Sat Oct 28, 2023 12:27 pm It looks like the very positive IOD has dropped to +1.58 from a recent high of +2.16 on October 15th.


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tpweather wrote: ↑Sat Oct 28, 2023 12:42 pm

tron777 wrote: ↑Sat Oct 28, 2023 12:27 pm It looks like the very positive IOD has dropped to +1.58 from a recent high of +2.16 on October 15th.


Oct-28-IOD.png

Good news and one of the items that was really bugging me and how it would translate to the winter

tron777 wrote: ↑Sat Oct 28, 2023 12:52 pm

tpweather wrote: ↑Sat Oct 28, 2023 12:42 pm

tron777 wrote: ↑Sat Oct 28, 2023 12:27 pm It looks like the very positive IOD has dropped to +1.58 from a recent high of +2.16 on October 15th.


Oct-28-IOD.png

Good news and one of the items that was really bugging me and how it would translate to the winter

Lots of changes going on right now Tim with the PDO rise (although still negative just not as deeply negative as it once was). The IOD is lowering a bit now and the El Nino getting another WWB as we speak although I currently don't see it making the Nino much stronger then it already is. I still wonder if we have already peaked or does it hold on a little while longer before peaking. That part of the equation I am not certain about.

tpweather wrote: ↑Sat Oct 28, 2023 12:59 pm

tron777 wrote: ↑Sat Oct 28, 2023 12:52 pm

tpweather wrote: ↑Sat Oct 28, 2023 12:42 pm

tron777 wrote: ↑Sat Oct 28, 2023 12:27 pm It looks like the very positive IOD has dropped to +1.58 from a recent high of +2.16 on October 15th.


Oct-28-IOD.png

Good news and one of the items that was really bugging me and how it would translate to the winter

Lots of changes going on right now Tim with the PDO rise (although still negative just not as deeply negative as it once was). The IOD is lowering a bit now and the El Nino getting another WWB as we speak although I currently don't see it making the Nino much stronger then it already is. I still wonder if we have already peaked or does it hold on a little while longer before peaking. That part of the equation I am not certain about.

Hey Les and agree hard to say for sure if its peaked but imo it has peaked. Having a weaker El Nino imo tends to help us in the winter for folks that want cold and snow. Many other factors of course but a weaker El Nino tends to keep a really strong southeast ridge less likely. Does not mean we won't have bouts of the southeast ridge like this past week and of course not but they tend to be broken up because the stj is strong and moving along to help push it out to sea and troughs in the eastern part of the country tend to occur more often as well.

airwolf76 wrote: ↑Mon Oct 30, 2023 3:32 am NOT TO GET INTO TOO MANY DETAILS FROM WHAT I HAVE BEEN LOOKING AT IT SEAMS THIS WINTER WILL END UP 125-150% OF AVERAGE SNOWFALL WITH AVERAGE TO SLIGHTLY BELOW AVG TEMPS.