Stormchaserchuck1

Negative PNA After the lowest daily PNA since 2017, 8 years, in May, the PNA is forecasted to fall below -1 again June would be the 4th consecutive month with negative PNA I rolled forward the March-April-May PNA and April-May-June PNA to the following Winter, to see if it leads anything. Surprisingly, there is no PNA signal the following Winter.. correlation is near 0 in the North Pacific. So to say that this Spring/early Summer PNA is going to lead the Winter is not completely right. There is, however, a NAO signal. Negative PNA March-June puts the probability at about 56-57% that the Winter NAO will be negative [correlation of below maps is opposite] US temps for the following Winter are neutral, for the -PNA rolled forward. About the best you can hope for given the occurrence.

Final tallies are in for Apr-May SLP pattern of most active Atlantic Hurricane seasons since 1995: VS ACTUAL Tell me what you think, I think it's close to opposite I think with this the median we can expect this season is 13-14 Named Storms.. of course there are many other factors.

Negative PNA After the lowest daily PNA since 2017, 8 years, in May, the PNA is forecasted to fall below -1 again June would be the 4th consecutive month with negative PNA I rolled forward the March-April-May PNA and April-May-June PNA to the following Winter, to see if it leads anything. Surprisingly, there is no PNA signal the following Winter.. correlation is near 0 in the North Pacific. So to say that this Spring/early Summer PNA is going to lead the Winter is not completely right. There is, however, a NAO signal. Negative PNA March-June puts the probability at about 56-57% that the Winter NAO will be negative [correlation of below maps is opposite] US temps for the following Winter are neutral, for the -PNA rolled forward. About the best you can hope for.

I don't think the decadal state is going to change anytime soon.. June will likely be the 4th consecutive month with -PNA. I think there is intuition that what is happening is going to continue forward, but what global warming is, is a more general thing than the current state of the global pattern.

I think it's really silly that global warming is moving index patterns. This isn't something that is "maybe" to me, or "wait until the next decade". We have been in a west-based La Nina global state (tropical forcing on the dateline), and it has flexed the SE ridge along with probably a +AMO. I'll give that Winters are probably +3-4F warmer, but then you can correlate everything to what's going on everywhere else almost 100%. The biggest anomalies were Dec 2022 and March 2023, something was happening that did not let -NAO/-EPO penetrate.. it's probably connected to a Strong El Nino the following year and record Atlantic SSTs for 2023 and 2024. Since then -NAO's have run cooler over the last 2 Winters. 83% of Winter months have been +NAO since Dec 11.. 14 years. Something like 70% of months have been -PNA. It's no mystery at all why we are in a snowfall drought. I actually thought that it should have started sooner. I think he's right that things are getting warmer (shocking) but is 20-30 years ahead of time, using the last 7 years to say it's somewhat of a permanent thing. The thing is, the next few Winters might be like this as the decadal states aren't changing anytime soon.

I think what you are saying bluewave is that the NAO would be -0.75 if 09-10 happened today, vs the -1.5 that it was back then.

With the wind blowing, this evening felt colder than a lot of Winter days lately.

13/7/4

DCA: +1.6 NYC: +1.8 BOS: +2.0 ORD: +0.8 ATL: +0.6 IAH: +0.7 DEN: +2.5 PHX: +2.7 SEA: +1.0

I don't think so.. 09-10 was the most -NAO Winter on record, since the 1800s. Part of that is an elongated trough from the eastern US to Europe. I hear what you are saying, that a SE ridge has been happening for the last 10-15 years, but part of that is the NAO SLP not being negative. If the upper latitude pattern was the same (+PNA/-AO/-NAO), we would most definitely see snowstorms repeated again. You posted an Atlantic map of 09-10 a few pages back in the EA analysis.. Unless you are saying that type of Atlantic pattern is no longer possible? 80% of months during the year above average.. so even without indices you can say it's 75-80%, but there are definitely climate phenomenon that have led to this snowfall drought. I think you are putting too much stock on the last 10 year wrt climate indices.

Global warming should favor more high pressures, the problem is that the high pressures are happening at the mid-latitudes vs upper latitudes. I think we are still near a peak in the -PNA/-PDO.. it may take some time to wind down, but I do think something like a really active sun could create more low pressure systems (+PDO). The 2040s should be a really nice time with -NAO decadal and +PDO decadal, but by then the global temperature may have caught up. I don't see however how the warmth near Japan is global warming, it's not like they are giving off a lot of pollution. Maybe a slowing of ocean currents is warming the west side in the Pacific and Atlantic? PDO has been recorded to have many swings, so for now you might say it is a cycle we are in.

Daily PNA just hit the lowest since July 2017.. almost 8 years. And we even had a +600dm block in December 2021. These are the lowest daily readings since 2017: 2025 5 20 -2.02187 2025 5 21 -2.16265 2024 5 21 -1.69923 2024 5 22 -1.69731 2023 5 29 -1.57961 2023 3 28 -1.65316 2023 3 29 -1.54037 2022 11 30 -1.6506 2022 12 1 -1.76059 2022 12 2 -1.67042 2021 12 22 -1.5209 2021 12 23 -1.86403 2021 12 24 -2.08356 2021 12 25 -1.95318 2021 12 26 -1.76863 2021 12 27 -1.73472 2021 12 28 -1.6659 2021 9 30 -1.88225 2021 5 17 -1.68592 2021 5 18 -2.00071 2021 5 19 -1.88333 2021 5 20 -1.82705 2021 5 21 -1.69829 2021 5 22 -1.58023 2020 3 22 -1.64837 2020 3 23 -1.85732 2020 3 24 -1.79302 2020 3 25 -1.88764 2020 3 26 -1.93435 2020 3 27 -1.82528 2020 3 28 -1.73653 2020 3 29 -1.57907 2019 10 7 -1.58045 2019 10 8 -1.8704 2019 10 9 -1.96813 2019 10 10 -1.69351

Regarding Arctic ice melt.. I would say until we break past previous trend line (lower than all time record, by now actually much lower), we are going to be stuck in this -PNA/+NAO Wintertime pattern. Call it my intuition, but there seems to be a bit of a see-saw between melting the arctic ice and high latitude blocking in the cold season. Not going lower has amped a ridge in the eastern US, Europe, and Japan.

+QBO and cold-ENSO strongly favor cold Stratosphere 10mb. I came up with the ENSO/QBO correlation in 2008 and it has worked almost every Winter since.. but the Stratosphere doesn't always translate to 500mb/the surface. Last Winter is a good example, it was record breaking +QBO at 50mb I think, and it was one of the coldest Nov-Feb Stratosphere's on record. March 10mb actually has a near 0 correlation to the QBO state, and March ended up having a very warm Stratosphere. That Winter was pretty uniform in the Stratosphere, as far as ENSO/QBO goes. The Winter before was Strong El Nino/-QBO and we did have 4 Winter Stratosphere warmings (didn't quite make it to the surface that much though). There has been some tendency for -QBO and negative-ENSO to have cold December's, but we don't really have enough data to make that a strong conclusion.. I just remember on these boards in 2005 we were using the 1989 analog because of good -QBO/cold-ENSO and it worked out really well. Remember QBO is a Stratosphere index, 30,000+ feet up, so to correlate it with things like the Pacific Jet is hard because topographic features, and pressure patterns, effect the surface patterns more. Something like Asian Mountain Torque I would say is more important. Here's the cold season QBO-500mb correlation... nothing goes over 0.3 and the anomalies are spotty everywhere.. pretty random. I think it might work with other factors though. HM is really good at describing the QBO interacting to become a surface variable. I mean.. I don't know.. this cold season-QBO correlation (below) isn't that bad in regard to how the index is measured: Goes with a +QBO favoring Stratosphere coolings and eventual +AO. Look at how it interacts with the mountains in Asia (low pressure above the Himalayas, high pressure below)

Beautiful morning, beautiful sunrise, pinks, purples, and blue-grey. Everything is green from all the rain

I think that as long as we keep repeating this Summer pattern of +AO, that has been so common since 2013, the Winter NAO will have a tendency to positive, and probably PNA-negative, WPO-positive as well. Big +AO on models through the 2nd week of June. This is the same pattern as the last 12 years:

Thanks for the roll back bluewave! The thing that I hated most about the 09-10 storms is that it warmed up in between them. I always fantasized a 6'+ stacked snowfall, but while close they did melt a lot in between.

I think this is so interesting - I've talked before about ENSO subsurface trends, and how it correlates with the N. Hemisphere pattern more than ENSO SSTs, OLR, 850mb winds, etc. Now, we are currently getting a healthy Kelvin wave that has changed the central-ENSO-subsurface in a few weeks from -1c to about +2-3c. Now, we have a strong +AO - about as strong as it's going to get at this time of the year. I rolled that forward to the following Winter, and got an El Nino-like pattern of a warm December, followed by a cold February The STJ pattern currently projected looks like El Nino for the next 3-4 weeks All this while a strong Kelvin Wave is warming the central-ENSO-subsurface in now-time. I've said before that the effects of such a happening are immediate - see how these El Nino aspects are happening around this coherent wave? It happens that way quite often.

Strong +AO for the next 2 weeks should keep Arctic Summer Ice melt relatively below normal to start the season, compared to the last 15 years. Lots of cold 500mb anomalies over the Arctic circle.

All this stuff about the "Pacific firehose near Japan" is linked to the WPO, and positive phase of that index.

+WPO has been linked to Indian Ocean warming. Indian Ocean SST patterns may be decadal, although the long term trend is generally up.

It was strong -QBO, too, which goes with El Nino for Stratosphere warming

7-day code red in the E. Pacific

The AMO may have an imapact: -AMO ibb.co/bR3LvKW+AMO ibb.co/KctZCPm-AMO ibb.co/wKX4YCC+AMO ibb.co/sFSwm0j I don't know what the numbers are at 40N.. Maybe it is +3F. +WPO flexes the SE ridge further north when coupled with -PNA, and as Ray pointed out it has been positive every Winter but 1 since 16-17 I don't think that we are seeing more of a SE ridge because of global warming. I think that whatever the global temperature increase is divided by latitude is what that impact is.

I'm tired of global warming being blamed for the Winter SE ridge, especially during -AO/-NAO periods, when the Pacific has been in +WPO/-PNA. This map makes sense to me in regard to those 2 patterns and downstream effects. Global warming makes a +2F overall difference, but that's about it. It's not some unicorn pattern that is causing new things, like a more impactful SE ridge. There is meteorology involved, everything that happens has a reason. The global warming effects are global, but not localized.