bluewave

I am just trying to keep it real. The only time that optimism or pessimism are relevant is when you can have some impact on the outcome. We still haven’t devised a weather control device yet.

The current cooler pattern in the East is due to the stronger MJO 5-6 region forcing than we have usually had in recent early Septembers. It’s one of the few times of the year when it’s actually a cool signal for us. Could also be combining with other factors previously discussed in this thread keeping the Atlantic unusually quiet. Since there continues to be sinking air and the AEW wave train is pushed further north than usual into the Sahara.

The one early snowfall indicator which has worked for every La Niña winter in NYC going back to the 95-96 has been the December La Niña snowfall. Years with 3 or more inches December have gone on to above normal seasonal snowfall. Every December with under 3” has had a below average snowfall season. This is why December is so important with La Ninas around NYC. 22-23….Dec snow…..T……season….2.3 21-22…..Dec snow….0.2…season…..17.9 20-21…..Dec snow….10.5…season…38.6 17-18……Dec snow….7.7…..season…40.9 16-17…….Dec snow…3.2…..season…30.2 11-12…….Dec snow….0…….season….7.4 10-11…….Dec snow….20.1….season….61.9 08-09…..Dec snow….6.0……season….27.6 07-08…..Dec snow…..2.9…..season….11.9 05-06…..Dec snow…..9.7…….season…40.0 00-01……Dec snow….13.4……season….35.0 99-00…..Dec snow…..T……….season….16.3 98-99…..Dec snow…..2.0……..season….12.7 95-96…..Dec snow…..11.5……..season….75.6

Sure. There can always be a big difference in snowfall for CNE and points north and NYC. That’s why it has been more important to get a favorable Pacific in 20-21 and Jan 22 than we got with the blocking patterns in Dec 22 and Mar 23. We used to be able to get by with a hostile Pacific with -AO -NAO like we had from the 50s into early 70s when the SSTs to our east were much colder. Now we just get the Greenland Block linking up with the Southeast Ridge around storm time.

Snowfall is always tricky going into a seasonal forecast since one storm can make a big difference. While NYC and Boston obviously missed out last few seasons, we did get that localized stationary snowband over Central NJ. So while the general temperature tendency can be easier to detect for the seasonal models, snowfall forecast is usually more challenging.

The funny thing is the Euro did a great job with the U.S. summer temperature forecast. But the forecast of over 20 named storms and 200 ACE was too high in the tropical Atlantic. So it’s interesting that the model can hone in on one set of circumstances but completely miss another. As for next winter, we would need some type of mismatch which would mute or shift the predominant -PDO pattern all the seasonal models have. So not sure if what happened in the Atlantic will be relevant beyond some extra SST warmth and fewer wave breaking events in the North Atlantic from a large number of tropical systems. My guess is that the very high ACE years created these wave breaks which lead to more -NAO development and better snowfall outcomes. But we are missing that this year so far. We would need some type of big mismatch for next winter to shift off of this type of look. This summer featured one of the strongest ridges south of the Aleutians and near New England .So the seasonal models really focus in on the Aleutian Ridge and Southeast Ridge next winter. But as always we’ll need to see what actually happens with the atmosphere next winter to know if the models are onto the correct idea. At the very least it looks like this will be our 10th warmer than normal winter in a row for the Northeast in places like NYC. But the details including the magnitude of the warmth and how much snow are difficult to guess at before we get more clues in the coming months.

First time since 1968 with no Atlantic named storm formations between August 13th and September 3rd which was a developing moderate El Niño summer into winter.

The record heat in Japan and adjacent marine heat wave have been two of the more extreme heat records last few summers around the world. It’s why this -PDO has been more defined by the warm pool in those areas a rather than the cold pool so far near the NE PAC. To have two consecutive summers with this big a jump above any previous records is very impressive.

We probably could have challenged the 2012 extent record if the record blocking this summer was closer to Canada and Greenland like in 2012. The 500mb block back in June was the strongest ever recorded for that part of the world for the month. But it shifted closer to Svalbard later in the summer and spared Greenland and the Canadian Arctic.

The JMA winter 2013-2014 forecast issued in October 2013 was one of the best ever for a seasonal model forecast. JMA October 2013 forecast https://ds.data.jma.go.jp/tcc/tcc/products/model/map/7mE/map1/pztmap.php Verification

Canadian high pressure should dominate this week with good radiational cooling in the outlying areas. But it appears that we are back to the measurable rain on weekends pattern. Looks like the frontal passage this past weekend will occur again next weekend. Comfortable temperatures and humidity running below average for early September.

Even though the Euro will likely turn out to be too high with the forecast for 20-25 named storms and over 200 ACE, the U.S. temperature forecast for the summer was very good. So this tells there are elements of the climate system that these seasonal models can handle an others they can’t. It will be interesting to see if the Euro does as well with its winter temperature forecast and 500mb pattern next few updates on the 5th of each month.

One of the reasons the Atlantic has been so quiet last few weeks is due to the ITCZ shifting north into the Sahara.

It’s the first time in known history that a El Niño summer ahead of a winter ONI of +2.0 or greater had 7 named storms and 2 category 4 hurricanes develop between August 20th and 31st to be followed by a developing La Niña the next summer with no new storms during this period. 2023 New developments between 8-20 and 8-31 TS Gert TS Emily Cat 4 Franklin TS Harold Cat 4 Idalia TS Jose TS Katina 2024 No new developments

This is an unusually strong MJO 5-6 pattern for early September. It’s one of the few times of the year when we get a cooler to closer to normal temperatures from these phases. So a nice change from recent early September patterns which have been much warmer.

This looks like it will be one of the strongest -PDO summers since 1950. The -PDO pattern was so strong that year that it produced a +13.0 January in Atlanta. While this is not meant to be a forecast for next winter, it just shows what is within the range of possibilities should we get a strong enough Aleutian ridge and deep enough trough out West. We already had a +13.2 with the 21-22 La Niña and -PDO at DFW in December 21. Extreme months like this usually pop up in forecasts very close to the time period. So it’s not usually something that we can forecast from so far out. Hopefully, we get some type of mismatch pattern next winter that takes an extreme winter month off of the table. But it’s something to just be aware of with such extreme -PDOs. https://www.ncei.noaa.gov/pub/orders/IPS/IPS-017CC821-F4F4-4CF6-868A-42E597844BF5.pdf

The atmosphere is becoming so moist that we don’t even need a tropical storm or hurricane to produce this type of extreme flash flooding anymore. We began to see this back in August 2011 when another unnamed low pressure system with training thunderstorms produced more impressive flash flooding in spots than Irene did a few weeks later. The same went for the unnamed system at Islip in August 2014.

Historic warmth for Svalbard.

The forecast from a week ago was actually pretty good. This weekend was always about a front coming through. The only difference is the front slowed down a little from the forecast last Saturday. New run Old run

We are on track for one of strongest -PDO summers on record as the daily index declines again. 2024 -1.55 -1.33 -1.52 -2.12 -3.00 -3.16 -2.97

Back to back top 10 wettest summers for me. Time Series Summary for NEW HAVEN TWEED AP, CT - Jun through Aug Click column heading to sort ascending, click again to sort descending. 1 2009 17.52 0 2 2006 17.45 1 3 2011 17.38 0 4 1972 16.54 0 5 1955 15.30 0 6 2003 14.55 0 7 1952 13.87 0 8 2024 13.77 1 9 2023 13.45 2 10 1950 13.08 0

Yeah, looks like this was the first time that HVN had 30 days with a 75° or higher dew point.

You are missing the point. We are discussing what has already happened and the strengths and weakness of the approaches used over the last decade since the 15-16 super El Niño. You should cut the scientific climate and weather forecasting community some slack since these changes to our climate are happening faster than some of our older technology based models can keep up with . People are just doing the best they can with the technology we have available at the time. The weather and climate is an open and transparent system where everyone can see the results. Big pharma is different since it’s always not immediately obvious whether all the results of a study have been disclosed. So you are making an apples and oranges comparison.

The AMO itself may not be as relevant to the overall North Atlantic SSTs if we continue to see these subtropical record warm blobs east of New England and the Canadian Maritimes. It could result a the shift in tropical cyclone tracks with some areas seeing more activity and other less. But it will be interesting to see how things go in coming decades. https://www.nature.com/articles/s41598-017-11046-x Over the recent few years, striking changes in Atlantic SSTs have occurred in the subpolar gyre, where the cold anomaly that developed from 2013–2015 was termed the ‘cold blob’ in the press13. This cold anomaly resulted from extremely harsh winters of 2013–2015, characterised by strong surface heat loss14 which resulted in persistent cooling of the upper ocean15 and drove deep ocean convection16, 17. Here, we assess the impact of this cooling on the AMO index, and evaluate the observed changes over the past 3 years relative to the cold AMO period of the 1990s. The AMO index, however, masks any spatial distributions in SST changes, and while the AMO index is negative, the subpolar cold anomaly is accompanied by a warm anomaly in the subtropics. We investigate whether the cold subpolar anomaly is likely to persist and consider how the present cold state of the AMO may evolve.