bluewave

I never said that it can’t snow. But those warm anomalies have resulted in North American snow cover dipping to decadal lows for early December.

The greatest winter warming over the last 75 year has been in the Upper Midwest. The good news for Great Lakes snow lovers is that the warmer lakes staying open longer are producing heavier lake effect snows. But the bad news is that the ice fishing season is getting shorter across the Upper Midwest.

The volatility in the snowfall has been well documented since the 90s in terms of more all or nothing snowfall seasons especially at the Long Island stations to the east like Islip. The drop in snowfall began with the 18-19 season. So this is a relatively recent down turn lasting only about 5 years. The previous 5 year period was among the snowiest on record especially on Long Island. The current warm winter streak has been unprecedented in the entire record. We have never experienced 8 warmer than normal winters in a row with so many months landing in the top 10 warmest. Also some of the individual monthly records like the +13.3 December 2015 and the 80° at Newark in February 2018 has never happened before. So the warmth has been remarkable for both the departures and the actual temperatures. Plus the departures are against the warmer climate period since the 90s. NYC Feb 23…+5.2 Jan 23…+9.8 Dec 22…-0.6 …………..+4.8 Feb 22….+1.4 Jan 22….-3.2 Dec 21….+4.7 ……………..+1.0 Feb 21….-1.7 Jan 21….+1.1 Dec 20…+1.7 …………..+0.4 Feb 20…+4.8 Jan 20….+6.5 Dec 19….+0.8 …………….+4.0 Feb 19….+0.9 Jan 19….-0.1 Dec 18…+2.6 …………….+1.1 Feb 18…+6.7 Jan 18….-0.9 Dec 17…..-2.5 …………….+1.1 Feb 17…..+6.3 Jan 17….+5.4 Dec 16….+0.8 …………….+4.2 Feb 16….+2.4 Jan 16….+1.9 Dec 15….+13.3 …………….+5.9

That’s one of the weaknesses with the entire online meteorological community on twitter. We really have to dig into why the models are showing a particular outcome and try to anticipate where the bias lies. My focus has been trying to identify model biases and taking things from there. That’s the main reason I have been anticipating warmer risks from mid to late December than any of the models were showing. Big meteorology firms don’t realize how much money they are leaving on the table by just relying on the actual long range model output without trying to anticipate what the model errors are.

But the long term convection is increasing faster over the parts of the oceans which contain the warmest MJO phases.

That the warming of the Western Pacific loads the dice for warmer winter outcomes in our area.

I began to suspect it after seeing the extreme warmth in December 2015 when we had a record MJO 5 for a super El Niño. But we recently got confirmation in 2019 that this is the case. It’s not just chance that we have had 8 warmer than normal winters in a row which never happened before. https://www.nature.com/articles/s41586-019-1764-4 Twofold expansion of the Indo-Pacific warm pool warps the MJO life cycle M. K. Roxy, Panini Dasgupta, Michael J. McPhaden, Tamaki Suematsu, Chidong Zhang & Daehyun Kim Nature volume 575, pages 647–651 (2019)Cite this article 12k Accesses 91 Citations 498 Altmetric Metrics details Abstract The Madden–Julian Oscillation (MJO) is the most dominant mode of subseasonal variability in the tropics, characterized by an eastward-moving band of rain clouds. The MJO modulates the El Niño Southern Oscillation1, tropical cyclones2,3 and the monsoons4,5,6,7,8,9,10, and contributes to severe weather events over Asia, Australia, Africa, Europe and the Americas. MJO events travel a distance of 12,000–20,000 km across the tropical oceans, covering a region that has been warming during the twentieth and early twenty-first centuries in response to increased anthropogenic emissions of greenhouse gases11, and is projected to warm further. However, the impact of this warming on the MJO life cycle is largely unknown. Here we show that rapid warming over the tropical oceans during 1981–2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900–2018 and at an accelerated average rate of 4 × 105 km2(the size of California) per year during 1981–2018. The changes in the Indo-Pacific warm pool and the MJO are related to increased rainfall over southeast Asia, northern Australia, Southwest Africa and the Amazon, and drying over the west coast of the United States and Ecuador

Especially with the bias corrected charts.

Higher ocean heat content is increasing the convection in the warmer MJO phases.

It doesn’t matter anymore whether we have an El Niño like this December or a La Niña like last January. We keep getting these ridiculous Pacific Jet extensions that bring record warmth to North America. My guess is that all the warmth in the Western to Central Pacific MJO regions are driving this phenomenon. This time with the orientation in the ridge, the warmest departures will probably line up further west than last January. But even in a warming planet, it’s noteworthy to get two consecutive winters with monthly departures so high for the North American continent.

I don’t mind the back and forth as long as people leave the personal digs out of the picture. We can have disagreements without being nasty about it. I actually started my early online weather explorations by becoming a contributor to the old Weatherpoint Counterpoint shows back on Accuweather with JB and the late Ken Reeves. As much as I disagreed with JB through my emails they would discuss on the show, we always kept it civil. I used to get a chuckle about over how animated JB got by some of my questions. But he would always be gracious in our off the show e-mail exchanges. Then I heard how impressed he was by reading some of the posts in this forum. While I had plenty of disagreements with his positions, he did say that some of the talent he saw in this forum rivaled or exceeded what he experienced in the industry.

One of the weaknesses of the entire weather forecast industry right now is how much money they are spending on high tech approaches when several low tech approaches discussed in these threads are yielding better forecast results for a fraction of the cost. But the people running those big organizations get stuck in a very regimented way of thinking about how to recruit talent. They don’t realize how much money they are leaving on the table.

Same crazy jet extension that we got last January.

Yeah, that has been one of my concerns. The previous top 5 wettest first weeks of December in Seattle were mostly La Ninas. I am hoping that we can see some type of backloaded El Niño effect later in the winter. Don’t want to see these Niña-like undertones mess things up. But I reserve my judgment until we get closer to that time. Would like to see some weakening of the Northern branch allowing more of a STJ dominant pattern with some blocking. Time Series Summary for Seattle Tacoma Area, WA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Dec 1 to Dec 7 Missing Count 1 2023-12-07 5.78 0 2 2007-12-07 5.68 0 3 1989-12-07 4.06 0 4 1970-12-07 3.83 0 5 1975-12-07 3.63 0

Its a combination of the very strong El Niño and the Maritime Continent MJO phases which excite the East Asian jet leading to the jet extension. That’s why we have been using El Niño MJO composites. So it’s effectively a very strong El Niño with Niña-like influences via the MJO phases. One of the weaknesses of the seasonal models is that they usually can only see the correct ENSO state and not the MJO. So they completely missed the Nina-like record rainfall and strength of the Northern Pacific Jet which lead to the wettest first week on December in the Pacific Northwest. So the +EAMT Eric mentioned is related to the MJO and El Niño interaction. MJO and TorquesFrictional and mountain torques induced by the MJO circulation anomalies are responsible for the angular momentum exchange between the atmosphere and the solid earth. The MJO, Atmospheric Angular Momentum and the Length-of ...

Yeah, it’s just that the colder winter months since the 15-16 super El Niño have become few and far between. I was excited about the cold January 2022 pattern but disappointed for western sections since the lack of a decent -AO kept the best snows near the coast. Late January into February 2021 was also a great pattern. Allsnow did a great job highlighting the December 2020 snowstorm potential from later in November 2020. So not sure why people are giving him so many weenies. He loves a great pattern as much as I do. And will highlight it when it’s actually about to occur. But when we see such a hostile Pacific like we have now it can’t be ignored.

Yeah, it’s just that combining such a strong El Niño with MJO 4-7 phases results in a much warmer December pattern than usual for much of North America that we are seeing this month.

The warming in this case includes the near record SSTs in the western El Niño regions in addition to the warmer Maritime Continent MJO 4-7 phases. My reference to RONI was in the way GaWx was hypothetically using it in his question. Not that RONI wasn’t a thing. But that perhaps the lower RONI values for this event reflected the much warmer SSTs than normal SSTs near the MJO 4-7 regions during such a strong El Niño event. My guess is that the RONI or MEI would be higher if the WPAC was as cool as it was 30 years again and the Nino regions didn’t have competition from the forcing extending further west.

Models are starting to show 5 sigma jet speed departures north Japan even before the main extension later this month. The EAMT that Eric references is a direct result of the MJO in the Maritime Continent phases interacting with the El Niño.

Models are still playing catch up with how warm North America is going to get from mid to late December with a crazy just extension like that. International falls is already around +10 after one of its warmest starts to December. So there is a chance that those double digit departures could be maintained. Not good news for people that like ice fishing up in those areas.

That big +EPO showing up for mid to late December will probably result in numerous stations across the Northern US experiencing yet another top 10 warmest December added to the warm start to the month. The departures especially around International falls may creep close to double digits.

Yeah, I pretty much figured this out. His charts are the only ones in the industry that have the bold color change at the -8 temperature departure from blue to green while maintaining a more subtle orange to darker orange color change +8. This directs your eye to the colder side making the colder departures seem more substantial.

Through the rich get richer mechanism. The WPAC warm pool is one of the regions that sees an increase in tropical convection with warming SSTs. The paper you mentioned discussed subsidence regions in other areas of tropical oceans with warming. The previous papers I posted about the WPAC show increased convection there with rising SSTs and stronger MJO phases. https://www.pnas.org/doi/full/10.1073/pnas.0601798103#:~:text=The “anomalous gross moist stability,because of enhanced moisture convergence. The “anomalous gross moist stability” or “rich-get-richer” mechanism (12) hypothesizes that the upped-ante differential moisture increase will yield increased precipitation within the convection zones because of enhanced moisture convergence. This mechanism also contributes to drying outside the strong convection zones and likewise should yield an approximately fixed spatial pattern whose amplitude grows in time with the tropospheric warming. Among these are drying regions in Central America, the Caribbean, equatorial South America, and along the Atlantic intertropical convergence zone. Precipitation increases tend to occur inside the convection zones, including increases in the Southeast Asian summer monsoon. Increased precipitation also occurs in the equatorial Pacific, associated with changes in the dynamics of the equatorial cold tongue and local sea-surface temperature increase (15–18).

Yeah, that would be one I would love to experience also from the 1800s. My number one pick from the 1700s would be NY Harbor freezing over in 1780. My guess is that January 1780 averaged around 15°-17° in NYC. The coldest recorded month since the late 1800s in NYC was Feb 34° at 19.9°. https://www.nytimes.com/2002/12/05/opinion/a-cold-snap.html In the winter of 1779-1780, New York Harbor lay frozen for five weeks. It was possible to walk to Staten Island. The Hudson River was a broken pavement of ice, and by spring nearly every tree in the city, and much of its furniture, had been burned for heat. Those were the days before official weather records were kept, so no one knows exactly how cold that terrible winter was, when even the Chesapeake froze over.