bluewave

It’s looking like another over the top warm up. So it will start out with onshore flow and warm mins. But some of that heat building over the Midwest will eventually come east. So probably some more highs in the 85-90° range for the usual warm spots NJ later in the month once the flow turns more SW. It’s the type of warm up which could erase most of the early month cool departures.

This could be the first time in the 2020s that the highest September temperature at Newark comes after September 15th. The high for the month so far at Newark was 86° on September 1st. Newark hasn’t had a September high this low since 2009. The cooler pattern is forecast to continue another week or so before we warm up later in the month. That’s when Newark has a chance to surpass the 86° high on the 1st. Newark warmest September temperatures 9-6-23….97° 9-4-22….93° 9-15-21….91° 9-3-20…..89° Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Sep max temperature Click column heading to sort ascending, click again to sort descending. 2024 86 27 2023 97 0 2022 93 0 2021 91 0 2020 89 0 2019 93 0 2018 98 0 2017 92 0 2016 94 0 2015 98 0 2014 95 0 2013 96 0 2012 92 0 2011 88 0 2010 98 0 2009 86 0

One of the possibilities is that the record Mediterranean and North Atlantic SSTs can shift the ITCZ further north than usual.

We haven’t had much success with -WPOs during La Ninas since 16-17 when the MJO has been phase 4-7. The only good -WPOs were during MJO phase 8 like in January 22. December 23 featured a strong -WPO but the MJO 4-6 helped pump the SE Ridge and we went snowless for the first time with one of the strongest December -AO patterns on record. We had the -WPO in February 2018 and the first winter 80° around NYC occurred as the MJO went through phases 4-7. The reason the February 2017 -WPO pattern featured a blizzard was also MJO phase 8. But the month was overall very warm due to the amplified MJO 4-7 prior to 8. Plus the more +PDO probably helped us out. December 22 MJO 4-6 Jan 22 MJO 8 Feb 2018 MJO 4-7 Feb 2017 MJO 8 after 4-7

Good radiational cooling tonight for the usual spots.

The last thing I want to do is make anyone sad. Just hoping we can get some degree of mismatch between this very strong -PDO and the pattern this coming winter. The 21-22 winter was a very interesting case. We didn’t get the strong MJO 5 signal that October which usually preceded our better La Niña winters. December was one of our warmest La Niña Decembers with the historic +13 at DFW. It was one of our strongest -PNA Decembers and the Aleutian ridge that month was one of the strongest on record. But we got the MJO 8 leading to the -EPO +PNA in January which really salvaged the winter from going the way that 22-23 did. That’s one example of a mismatch. But there could be a variety of other ways we haven’t seen yet since we are dealing in small sample sizes in this new much warmer era.While it may hard to shift the record 9 warmer than normal winters in a row pattern, I am hoping we get a chance next winter to better the 22-23 and 23-24 snowfall outcomes. Since there is more variance with snow we’ll just look for any opportunities we can get. But if the Aleutian Ridge and Southeast Ridge combo grows too strong yet again, then there is the chance that the winter could go the way of the last two. But not yet ready to give up on rolling the dice for at least a better snowfall outcome than the last two. Those details may not be known until we at least see how December goes.

Yeah, the strongest forcing that month near MJO 5 was right before the coldest part of the month around the 20th. It occurred about 2-3 weeks later than we are seeing this year.

The forcing shifting from the IO toward the Maritime Continent has been going on the last few weeks. The RMM charts have been pretty noisy. But the VP anomalies match the expected pattern progression this time of year. Plus there is often a lagged response so it’s no surprise the late August Maritime Continent forcing has manifested last few days.

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