bluewave

Nino 3.4 is struggling to get much past the 1.6 to 1.7 range on the dailies with the upper ocean heat so much lower than other strong El Niños. So the October daily peak was similar to September. Most El Niños show a decent jump from September to October. So the Euro seasonal is going to have one of its biggest misses on record for an October average forecast of 2.03. The CFS is actually going to be closer to the mark for its October forecast of 1.60. The current monthly average from OISST is 1.53. ECMWF 2.03 NCEP CFSv2 1.60 Current October OISST average 1.53.

Yeah, I had several posts showing the more south based based blocks with the warmer Atlantic SSTs in recent years. Also the tendency to get near record -AO months like last December with the NAO hardly going negative. The SW lean to the blocking is causing very large spreads between the AO and NAO. Some implicated the -PNA last December. But there were months in the older era with even deeper -PNAs that coincided with -AOs and colder NATL SSTs with blocks that didn’t build so close to New England. December 2022 2nd lowest December -AO on record behind 2009 and more south based block with the NAO hardly responding. AO -2.719 NAO..-0.15

Yes. The record NATL SSTs are probably the reason for the more south based blocking down to New England in recent years.

El Niños are usually cooler in the Southeast than the CPC and Euro seasonal. The colder departures further SW are more related the expectation on the Aleutian ridge north of Hawaii. This tends to promote downstream troughing near the SW instead of SE. Need a stronger Aleutian low north of Hawaii to keep the ridging near the East Coast in check.

That’s why I am not a big fan of the Aleutian ridge north or northwest of Hawaii. This persistent pattern for much of the last 8 winters tends to lower heights over the Western US and pumps the ridge in the Northeast. While the Euro seasonal raises the PNA in Canada, it still has the trough axis tucked underneath in the SW. The one hope is that we can cash in during any +PNA -AO intervals for a better snowfall outcome than last winter around NYC. But it would still be a record 9th warmer than average winter in the the Northeast if the trough axis remains near 115 west.

Yeah, the magnitude of the warmth increases the further north you get.

The warm departures on the warmer days will be more impressive than the cold departures on the colder days. That’s how the Northeast is on track for several stations having a top 10 warmest October. While the colder days have felt more fall-like, there has been no top 10 or record cold for this time of year.

We get the highs approaching 80° while Montana goes below 0°. Same old pattern of recent years with the cold dumping into the West. Plenty of time for the cold to moderate coming east. But we’ll still probably get 30s around NYC which will feel much colder following 80°.

I like the ensemble means better since those tercile maps lack the better definition.

The main challenge with the Euro seasonal is that it still has a trough near the SW in February. So storms ejecting from the SW could come out too far north without solid blocking on the Atlantic side. But I would still take my chances with that look compared to last winter. While it would be a record 9 warmer winters in a row for the Northeast, the snowfall would probably be better than last winter.

Even the Canadian which can sometimes have a cold bias has 80°.

Looks like the CPC is going with the Euro seasonal which has the warm Nino +PNA ridge to the north undercut by the -PDO trough near the southern Rockies. With a +PDO El Niño the trough would be over the Southeast. But it’s pulled west due to the -PDO in the seasonal forecasts. If we see the same error as the seasonal forecasts last winter, then the trough out West will be deeper pumping the ridge more in the East. You can see the Euro seasonal maintaining the Niña -PDO ridge north of Hawaii. But it also has the Nino +PNA ridge in Canada. Need to lose the -PDO and ridge north of Hawaii for the El Niño to be able to be the main driver.

It has been a split flow pattern. But the northern branch looks to dominate next weekend with the strong -PNA pattern. So some late season Niña-like 80° heat possible for the Northern Mid-Atlantic.

Models now indicating record 80° heat possible for next weekend. Maybe we can finally break the streak of rainy weekends. This would be the warm and sunny weekend which was so elusive all summer. Newark Area, NJPeriod of record: 1893-01-01 through 2023-10-21DateHighest maximum temperatures (degrees F 10/28 82 in 1984 81 in 1919 78 in 1989+ 10/29 78 in 1971 78 in 1946 76 in 1989 10/30 82 in 1946 80 in 1961 80 in 1950

The actual 500 mb pattern this month is classic MJO 6 with the deep Scandinavian trough and Hudson Bay ridge. I guess we can chalk it up to atmospheric lag since the MJO has been stuck in phases 4-6 for so many years. It’s as if the atmosphere isn’t even registering the subsidence near the Maritime continent with the near record +IOD.

The much lower upper ocean heat than usual for a strong El Niño is causing Nino 3.4 to struggle to push past +1.7 over the last month.

Blocking near Hudson Bay is classic La Niña in October. But this is even extreme for a La Niña. Somewhat similar to the La Niña in 2021. So not a very Nino-like North American pattern this October.

The first time the upper ocean heat anomalies during a developing El Niño were +.40 warmer in June than October. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

Relative to the means, the warm up next week will be more impressive than the cool down.

I liked the 17-18 winter into spring record snowfall much better than 18-19 and 19-20 following the record cold in November. Newark Area, NJPeriod of record: 1893-01-01 through 2023-10-19 Lowest minimum temperatures (degrees F)Top Record 2nd Record 3rd Record 11/10 25 in 2017 27 in 2004 27 in 1914 11/11 24 in 2017 25 in 1956 25 in 1933 11/12 25 in 2019 28 in 2017 28 in 1904+ 11/13 22 in 2019 24 in 1986 25 in 1920+ 11/14 18 in 1905 21 in 1986 24 in 2019 11/15 18 in 1933 21 in 1942 21 in 1905 11/16 15 in 1933 20 in 1967 22 in 1996+ 11/17 18 in 1933 21 in 1980 23 in 1900 11/18 19 in 1936 21 in 1959 21 in 1904 11/19 19 in 1936 21 in 2014 24 in 1903 11/20 21 in 1984 21 in 1894 22 in 1901 11/21 18 in 1987 21 in 1903 22 in 1910 11/22 17 in 2018 19 in 1987 22 in 1949 11/23 13 in 2018 21 in 1932 22 in 1949

I believe the WCS daily PDO updates are based on mantua PDO index and not the NOAA PDO index. So each version of the index varies from the other. Plus the key area north and NW of Hawaii is what matters for our sensible weather rather than the absolute PDO values. But when the are aligned like last winter into spring we had the strongly coupled -PDO trough in the West.

That is a very nice rise. We just need a decent cold pool and Aleutian low north or northwest Hawaii to push back against the tendency for too strong an Aleutian ridge. We want the El Niño to be the primary driver of the pattern. This way even if the winter continues the warmer theme of recent years, a juiced STJ can deliver better snowfall than last winter.

They are talking about localized sea level rise with the El Nino in the Tropical Pacific from the warmer SSTs not the ongoing global sea level rise. https://climate.nasa.gov/news/3286/international-ocean-satellite-monitors-how-el-nino-is-shaping-up/#:~:text=By October 1997 and 2015,the 1997 and 2015 events. Not all El Niño events are created equal. Their impacts vary widely, and satellites like the U.S.-European Sentinel-6 Michael Freilich help anticipate those impacts on a global scale by tracking changes in sea surface height in the Pacific Ocean. Water expands as it warms, so sea levels tend to be higher in places with warmer water. El Niños are characterized by higher-than-normal sea levels and warmer-than-average ocean temperatures along the equatorial Pacific. These conditions can then propagate poleward along the western coasts of the Americas. El Niños can bring wetter conditions to the U.S. Southwest and drought to regions in the western Pacific, including Indonesia. This year’s El Niño is still developing, but researchers are looking to the recent past for clues as to how it is shaping up. There have been two extreme El Niño events in the past 30 years: the first from 1997 to 1998 and the second from 2015 to 2016. Both caused shifts in global air and ocean temperatures, atmospheric wind and rainfall patterns, and sea level. The maps above show sea levels in the Pacific Ocean during early October of 1997, 2015, and 2023, with higher-than-average ocean heights in red and white, and lower-than-average heights in blue and purple. Sentinel-6 Michael Freilich captured the 2023 data, the TOPEX/Poseidon satellite collected data for the 1997 image, and Jason-2 gathered data for the 2015 map. By October 1997 and 2015, large areas of the central and eastern Pacific had sea levels more than 7 inches (18 centimeters) higher than normal. This year, sea levels are about 2 or 3 inches (5 to 8 centimeters) higher than average and over a smaller area compared to the 1997 and 2015 events. Both of the past El Niños reached peak strength in late November or early December, so this year’s event may still intensify. “Every El Niño is a little bit different,” said Josh Willis, Sentinel-6 Michael Freilich project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “This one seems modest compared to the big events, but it could still give us a wet winter here in the Southwest U.S. if conditions are right.”

The paper had an increase in PNA blocking only during the winter and not NAO blocking. The eruption was in January 2022. So 3-7 years wouldn’t be be until next winter. But it’s just one study so we’ll have to see if the winter PNA blocking increases in 24-25. So the record blocking over Canada since May is probably related to the general increase in these stuck 500 mb ridges in recent years and not the volcanic eruption.

Thanks. Just saw that. The blocking influence from the eruption on the composites is mostly during the winter and largely absent during the warm season. So maybe this is just a continuation of the 500 mb ridges that have been getting stuck in place during recent years as the planet warms.