bluewave

I don’t think that’s the case. We all know that those are departure maps and not absolute temperatures. So warmer departures at the start of December means highs in the 50s and lows in NYC in the 40s. Very tough to support a significant snow event at the coast with those temperatures. The NYC average split for the first week of December is 48°/37° the first week will average above that. Plus it’s very difficult to get a significant snow event at the coast with the current fast Pacific flow into the West Coast lowering heights out there and not letting a ridge lock in long enough out West.

You should never let someone else think for you. We have a great pool of talent on here. We turned out to be right about this not evolving like a typical east based event. Myself along with others were pointing out that the record WPAC pool was different than the way Paul was seeing this early on evolving like an El Niño before 1980. The structure of the OKC was also different. Whether this event tops at an ONI of of 1.8 to +2.0 or 2.0 to +2.2 is the least interesting aspect of this event IMHO. The big story is the record +30C warm pool from the Dateline back to the Maritime Continent. I can remember pointing out early on how the MJO 4-6 areas would rebound in temperature once the IOD peaked. There weren’t any tweets from Paul indicating that the WPAC would be so different from previous events. Instead we heard this this would be a classic pre 1980 El Niño. But none of those El Niños had the record WPAC warm pool and MJO 4-6 forcing to start December. Remember it’s not necessarily the exact ONI departures which count, but where the pool of +30C SST departures are located with the forcing which leads to our sensible weather. We are in a new era of marine heatwaves which provide competition to the ENSO. So instead of playing single El Niño notes, the atmosphere can respond like playing a chord with a mix of Nino and Niña notes. This will determine the Rossby wave and 500 mb pattern. The chart below is how much warmer the WPAC basin is than all other El Niños at the end of November.

The first hint something unusual was going on was when NYC tied the all-time lowest August temperature at the end of the month of 50°. Several NW suburbs actually dropped into the upper 30s on August 31st. This was followed up by 2nd lowest October temperature of 29° in NYC. The locally colder spots were able to dip below 20. The historic cold continued with widespread single digits on December 3rd.This was the 2nd earliest single digits on record in NYC. So nothing like the climate of the early 2020s. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Aug Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1986 50 0 - 1982 50 0 - 1976 50 0 - 1965 50 0 - 1885 50 0 Monthly Data for August 1976 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Lowest Min Temperature NY WALDEN 1 ESE COOP 37 CT DANBURY COOP 38 NY PORT JERVIS COOP 38 NY CARMEL COOP 39 CT WESTBROOK COOP 39 CT MOUNT CARMEL COOP 39 NJ CANOE BROOK COOP 39 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1936 28 0 2 1976 29 0 - 1925 29 0 - 1887 29 0 - 1879 29 0 Monthly Data for October 1976 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Lowest Min Temperature CT STAMFORD 5 N COOP 16 NY WALDEN 1 ESE COOP 17 NY PORT JERVIS COOP 18 Data for December 3, 1976 through December 3, 1976 Click column heading to sort ascending, click again to sort descending. State Name Station Type Lowest Min Temperature CT NORWICH PUBLIC UTILITY PLANT COOP 1 NY YORKTOWN HEIGHTS 1W COOP 2 NJ CHARLOTTEBURG RESERVOIR COOP 2 NY WALDEN 1 ESE COOP 3 NY BEDFORD HILLS COOP 3 NY PORT JERVIS COOP 4 CT STAMFORD 5 N COOP 4 CT DANBURY COOP 4 NY CARMEL COOP 5 CT MOUNT CARMEL COOP 5 CT GROTON COOP 5 NY MARYKNOLL COOP 5 NJ ESSEX FELLS SERVICE BLDG COOP 6 NJ CRANFORD COOP 7 NJ CANOE BROOK COOP 7 NY WESTCHESTER CO AP WBAN 7 NY SUFFERN COOP 7 NY MIDDLETOWN 2 NW COOP 7 NJ PLAINFIELD COOP 8 NJ LITTLE FALLS COOP 8 NY SCARSDALE COOP 8 CT WESTBROOK COOP 8 NY ISLIP-LI MACARTHUR AP WBAN 8 CT MIDDLETOWN 4 W COOP 8 NY DOBBS FERRY-ARDSLEY COOP 8 NJ JERSEY CITY COOP 9 NJ NEWARK LIBERTY INTL AP WBAN 9 NY NY CITY CENTRAL PARK WBAN 9

Yeah, 76-77 was the only winter I experienced with little ice age style extended cold. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Number of Days Max Temperature <= 32 Missing Count 1 1976-1977 45 0 2 1917-1918 42 0 3 1880-1881 40 0 4 1903-1904 39 0 - 1884-1885 39 0 5 1935-1936 38 0 6 1919-1920 37 0 - 1904-1905 37 0 - 1892-1893 37 0 7 1977-1978 36 0 8 1887-1888 35 0 9 1878-1879 34 1 - 1872-1873 34 0 10 1933-1934 33 0 - 1874-1875 33 2 Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Number of Days Min Temperature <= 20 Missing Count 1 1917-1918 48 0 2 1880-1881 46 0 3 1976-1977 44 0 4 1935-1936 43 0 - 1919-1920 43 0 5 1933-1934 42 0 - 1903-1904 42 0 - 1874-1875 42 2 6 1884-1885 41 0 7 1872-1873 40 0 8 1892-1893 39 0 9 1906-1907 38 0 - 1887-1888 38 0 10 1993-1994 37 0 - 1871-1872 37 1

I would consider it snowy since it ended with the 950 mb benchmark blizzard. Probably the only time in the last decade that a truly cold pattern emerged during the last week of December. But we still got the warm up around the solstice.

On the few occasions we do get extended cold like 13-14 or 14-15 it has been very snowy. Cold and dry really hasn’t happened here since the 70s and 80s. Walking to the bus stop in January 1977 was probably the closest I have experienced to what life was like during the little ice age. Luckily the next season was one of our greatest on record for snowstorms and the cold relaxed a bit. One of the worst on record for cold and dry was the -10 December 1989. Things seemed promising after the snowy Thanksgiving but cold suppression reigned in December.

Success in any endeavor is a careful balancing of science,art, persistence,and intuition. The skillful use of data can suffice when traditional notions of sample size seem too small. You don’t have to wait 100 years when seasonal forecasts which employed these methods have done very well recently.

It’s really contingent on the strength of the weather or climate signal that we are dealing with. When a signal is very strong a smaller sample size may be sufficient. But when the signals are weak there may never be a large enough sample size. There has been an extremely strong Western Pacific and Western Atlantic warm signal since the super El Niño in 15-16. This is why seasonal forecasts which have used some of these elements such as strong SE Ridge or WAR have been so successful. It was rare to be able to do this before the last decade when seasonal forecasts were more of a crapshoot due to weaker climate signals. So we were usually deprived of a large enough sample size unless the signal was so overwhelming like a super El Niño or very strong La Niña. Or a very strong temperature signal in one season which continued to the next.

I think Paul’s charts are similar to Allan’s MJO 7 El Niño December 500 mb composites. But that may be a little fast for phase 7 with convection still lingering further west into mid-December. We may eventually get to that look as the month progresses. We’ll see. https://www.americanwx.com/raleighwx/MJO/MJO.html

Yeah, a mild low 50s pattern to start the month with the warmer minimums dominating. While the highs aren’t that much above normal, the fast Pacific Jet is working against the -NAO influence. We may have a shot at 55-60° by mid-December as we lose the -NAO and the Pacific Jet continues on steroids.

November continues to be one of the few months of the year that is able to reliably produce colder departures at times. The monthly temperature increases from 81-10 to 91-20 have been more pronounced during certain months. Newark and Islip are compared below. The +1.0 or warmer months for either station were bolded. ……….EWR…..ISP Dec…+1.5….+1.5 Jan….+1.2…+1.3 Feb….+0.5….+0.5 Mar….+0.4….+0.6 Apr….+0.5…..+0.6 May...+0.6….+0.9 Jun….+0.3….+0.6 Jul…..+1.4…..+1.1 Aug...+0.6….+0.9 Sep….+1.0….+1.3 Oct…..+0.9..+1.4 Nov….+0.2..+0.5

Using the 850 mb temperature anomalies in recent months has been deceptive since the 2m temperatures have been running warmer across the CONUS. On top of that, raw model 2m temp anomalies forecasts have been running cooler than the actual temperatures and the MOS on the colder days. But most weather map providers don’t have MOS corrected 2 m temperatures. There has been very little cold in Eastern Canada this fall.

If you are adhering to the rules of sample size purism, then very few posts in this thread using El Niño winter composites have a large enough sample size. The possible subcategories this winter include questions of coupling, strength, location of warmest ENSO SST anomalies, record WPAC warmth for an El Niño, negative phase of PDO, early MJO 4-6 phases, competing marine heatwaves for forcing with ENSO, along with other factors. So there are going to be a naturally small number of past years which match this year. But that doesn’t mean we can’t try to use even a smaller sample size than we would probably want to to look for clues. Sometimes in forecasting we have to try and follow the spirit of the law so to speak when the letter of the law may be out of reach.

I picked a total of 7 El Niño years since 2000 which showed similarities in fall patterns to winter. A similarity doesn’t mean an exact carbon copy. Plus the increasing number of multiyear La Ninas may naturally create a larger sample pool of events to draw from than El Niños. We could probably reduce what officially counts as an El Nino by including coupling issues in years like 18-19 along with El Niños with -PDOs. Competing marine heatwaves may eventually result in a large enough sample size to change our expectations of ENSO events relative to climatology from earlier eras when these extreme marine heatwaves weren’t as prevalent.

A large number of individual years did work out as you posted a few posts back. My analysis covered a large portion of the CONUS. So cherry picking a few locations on the map that didn’t work out is missing the point. 20 years isn’t that small of a sample size. And if you were so concerned about the science, you wouldn’t have taken the name of a discredited stadium wave paper which proclaimed that global warming was going to level off after 2010 or pause until the late 2020s when the opposite has occurred.

There really isn’t much in the way of cold air near the coast even If a more amped pattern verifies since it’s all Pacific air getting stuck under the block.

The fast PAC Jet that keeps lowering heights along the West Coast is the main issue. Tends to suppress systems moving to our south and allow lows to our west to cut or hug the coast more. So some version of recent years issue of cutter, hugger, and southern stream suppression working against true BM tracks. Plus models have been underestimating the PAC Jet in the 6-10 day range most of the time since 18-19.

The correlation has worked out for every El Niño since 02-03. But for some reason, it didn’t really exist before that. The 3 coldest El Niño falls into the Plains and Great Lakes in 02, 09, and 14 expanded a few degrees eastward for the winter. Then the colder in Plains and warmer in the East El Niño falls of 06 and 18 repeated for the winter. I chalk this up to our new era of stuck and stagnant weather patterns. So a fall pattern can linger in some fashion into the winter.

I did find a relationship between fall (SON) temperature departures and winter CONUS departures. While this pattern just emerged in 2002, it has worked out each El Niño year since then.Very similar temperature departure patterns in the fall to winter. They fell into 3 groups. The first is the colder falls which preceded the colder winters. Next was the colder falls to the West and warmer along East Coast which repeated during the winter. The final group was the warmer falls across the the entire CONUS and the warmer winters across the Northern tier to Northeast. This fall has matched the warmer years of 2004 and 2015. But luckily, we didn’t reach the magnitude of the fall 2015 warmth. That would be a tough act to follow anyway. So somewhere in between 04-05 and 15-16 for fall departures. This would mean above average temperatures this winter near upper Midwest and Great Lakes to Northeast.

Luckily, the VP anomaly forecast into December near the dateline doesn’t look as extreme as in 2015. Same goes for the RMM response this month in 4-6 which looks less amplified. So not seeing any indication yet of that epic standing wave which developed. But even 25% to 50% of that warming would still be a warmer than normal pattern for us in December. As for later in the season, we’ll just have to wait and see how it plays out. Would like to see enough El Niño influence Jan 15th to February 28th to minimize any potential for MJO 4-6 or -PDO negative interference. I only mention that since there has never been an El Niño before with such an extensive +30C warm pool back to the Maritime Continent. In the old days El Niños had much cooler SSTs in the WPAC this time of year than we are seeing now.

We needed the strength of that one to eventually shut down the warmest MJO 4-6 phases we got in December. So while the rest of the season was warmer than average, it wasn’t nearly as warm. The blocking was able to take over later on and produce the record snowfall. So not sure if this El Niño gets strong enough to counter any warmer MJO 4-6 phases associated with that +30C warm pool near the Maritime Continent. We can hope that the warmer Maritime Continent forcing we are seeing now fades away by January and February and allows a typical backloaded El Niño response with blocking for snow even if it doesn’t get really cold. The last thing we want is MJO 4-6 phases mucking up the late winter El Niño response. So we have plenty of time to see how things evolve since we usually don’t expect much from the front end of El Niño winters.

Yeah, every single digit snowfall season in NYC was followed by a double digit one of at least 12.7”. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Next Season Total Snowfall 1 2023-04-30 2.3 ? 2 1973-04-30 2.8 23.5 3 2002-04-30 3.5 49.3 4 1919-04-30 3.8 47.6 5 2020-04-30 4.8 38.6 6 1901-04-30 5.1 25.4 7 1932-04-30 5.3 27.0 8 1998-04-30 5.5 12.7 9 2012-04-30 7.4 26.1 10 1989-04-30 8.1 13.4 - 1878-04-30 8.1 35.8 11 1951-04-30 9.3 19.7

Those VP charts are showing the MJO lingering in 7. The ultra long range guidance was trying to dampen the convection too much near the Dateline around the holidays. My guess is this is just the models losing the signal in the increased long range noise. As models get closer it’s easier for them to see the signal. New run Old run

Centrally or west based El Niños are colder when they are weaker than we have now like 02-03, 09-10, and 14-15. Those are the true Modokis. This event currently has some of the warmest Nino 4s on record behind 2016. In any event, we have plenty of time. Since nearly all El Niños are judged on Jan 15th to February 28th. So anything before then is a bonus and we usually don’t expect much. The hope is that we get a true Nino response later in the winter and not get interference from the MJO 4-6 regions. A cleaner El Niño response could allow us to surpass the snowfall totals of last year if we get good blocking later in the winter.

The latest EPS weeklies don’t move the forcing past MJO 7 in December as the warm pool is too strong near the Dateline. So it never achieves the classic MJO 8 look with the VP anomalies shifting well east in December. The last time Nino 4 was this warm in 15-16 it took until January for the MJO to shift over to 8-1-2. But while it was colder than when in the MJO 4-7 phases, it never got colder than average due to the overpowering jet stream off the Pacific. But we did see an eventual snowfall improvement due to blocking later in the season. The one caveat now is that the WPAC warm pool is stronger this year. So we may still get further competition from the warmer MJO phases. The RMM charts have been too fast in recent years to move the MJO out of the warmer phases. While the VPanomaly charts have been more reliable. But even they have been to fast to move the MJO to 8-1-2.