bluewave

We were discussing a nearly 384 hr GFS OP very low skill hypothetical which changes every 6 hours to pass the time since people have been so bummed out about a lack of snow. Just read back a few pages to see the many challenges the actual pattern will have to produce snow. These continuing challenges through December were outlined here starting back in the late fall. So we were outlining changes which would probably need to happen in order for NYC to break its 1 and 2 inch record long losing streaks.

Scouts can be overrated if you ever saw the movie Moneyball. The patterns only appear complex if you are missing the lowest common denominator or underlying reality.

Then you haven’t been following this thread recently since the wave dynamics leading to these patterns have been spoken about repeatedly. Most people on this forum know that a pattern which produces snow is contingent on cold air. We know that the pattern I outlined which produces the benchmark storm track needs cold air for snow.

Complexity is just an excuse for the inability to see the greater underlying repeating patterns throughout nature which includes weather forecasting.

Sometimes it is when the source regions are devoid of cold enough air as was the case on 12–05-20.

It was implied in my post since I just figured everyone realized that it had to be cold enough for that pattern to produce a 6”+ snowstorm in NYC. We get that pattern plenty of times when it is too warm for snow. So it’s necessary but not sufficient if cold air is lacking. Plus there are many times when some aspect of that pattern present when it’s cold enough but lesser amounts of snow occur.

It seems like we need luck these days to get the Pacific to relax. The amped up Pacific Jet in recent years keeps driving troughs into the Western US. The NYC 6”+ snowstorm composite taking in 19 events since the 09-10 winter shows how important it is to get the Pacific on our side. The primary feature necessary has been a strong 500 mb ridge over the Rockies in the West. The secondary feature has been a Greenland block. NYC 6”+ snowstorm composite of the last 19 events since 09-10 Days used: 1/31/2021 03/14/2017 12/26/2010 12/17/2020 02/09/2017 02/13/2014 02/08/2013 11/15/2018 01/22/2016 02/03/2014 01/26/2011 03/22/2018 01/26/2015 01/22/2014 02/25/2010 01/04/2018 03/05/2015 01/03/2014 12/19/2009

With a little luck we can sneak in a better +PNA look like 12z instead of 6z.But we know these long range GFS OP runs always change. I think it will again come down to seeing if we can get at least a transient break from the trough out West. 12z 6z

Great story. I started out with one of those sleds back in the late 70s. Bethpage State Park was the place to go back then. But transitioned to one of the plastic sleds since the older sleds with the metal runners would tip over more. Plus you had to get out of the way pretty quickly with so many people going down the hills at once.

1963 didn’t make the list for NYC but I can check other locations if you want. Number of Consecutive Days Snowfall < 2 for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Run Length Dates Period of record: 1869-01-01 to 2023-12-21 1 691 2022-01-30 through 2023-12-21 2 685 1972-02-24 through 1974-01-08 3 521 1918-04-13 through 1919-09-15 4 416 1912-12-25 through 1914-02-13 5 406 1997-02-09 through 1998-03-21 6 386 1991-02-27 through 1992-03-18 - 386 1954-01-12 through 1955-02-01 8 385 1931-11-28 through 1932-12-16 9 377 1971-01-25 through 1972-02-05 10 366 2006-02-13 through 2007-02-13

We just exceeded any of the previous snow droughts with under 2 inches from 80s and late 90s. So Pacific has never been this hostile before. Hopefully, we can break this streak before the end of January. Number of Consecutive Days Snowfall < 2 for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Run Length Dates Period of record: 1963-09-05 to 2023-12-21 1 676 2022-02-14 through 2023-12-21 2 631 1997-04-02 through 1998-12-23 3 358 1972-02-24 through 1973-02-15 4 355 1985-02-07 through 1986-01-27 5 348 1986-02-12 through 1987-01-25 6 342 2007-03-17 through 2008-02-21 7 339 2019-02-13 through 2020-01-17 - 339 2000-01-26 through 2000-12-29 - 339 1988-01-09 through 1988-12-12 8 333 2011-02-22 through 2012-01-20

The record warm pattern in Canada got started last May. The record SSTs in the WPAC generated the forcing which lead to historic ridge. Similar pattern to this December.

Great post. We can also add Newfoundland and Labrador to that list.

Now you can say this is a long range forecast and who knows if it will verify or not. But Jan 1-7 has a suppressed southern stream. Then the 8-15th has storms running to the Great Lakes and redeveloping too close our area in the fast split flow pattern. Jan 1-7 Jan 8-15

Anytime in the last 5 years when there was a trough in the SW we had issues. Either southern stream systems getting suppressed or very amplified systems tracking too far north and west. All our best winter patterns featured a solid ridge in the Western US.

Yeah, the rapid SST increase in the Eastern IO could favor the convection moving there in the coming weeks combined with the El Niño would favor an undercutting SW trough. It’s what you get when the MJO 2-4 El Niño composites are blended together. That SST rebound is following the IOD peak.

Yeah, I like manually correcting the model biases and arriving at a composite that I feel will work given the various factors at play and known model biases. Everyone gets to see the raw model output. So to take it to the next level you need to have a reasonable guess where the model errors and biases are. A bit like what the MOS numbers do for various locations but correcting the actual 500 mb temperature maps. I would love to automate my manual process and develop a monthly subscription based app that corrects all the model output.

I am sure for them it was a small price to pay for possibly setting the NJ state record for largest wave ever surfed.

The globe is having one if its warmest Decembers on record. That small postage sized stamp of cold in Eurasia is rapidly reversing. North America is having one of its warmest Decembers on record with some of the lowest snow cover. NYC Metro has experienced 20 to 30 top 10 warmest months since 2015 to only 1 single top 10 coldest one. The Northeast happens to be one of the fastest warming regions of the planet along with the NW Atlantic. You are mixing apples and oranges when you mention politicians and activists. First, that is a completely separate field which involves policy. My focus is on the actual patterns and how to adapt to them on an individual basis. I don’t support any climate initiatives or proponents that promote schemes which will raise taxes or energy bills. Prices are already through the roof in this economy so higher energy bills or carbon taxes will just turn more people off from discussing the warming planet.

I was talking about the inherent EPS barrier effect bias involving convection near the Maritime Continent. So when I saw the late November VP anomalies forecast I knew the signal through 4-7 would be stronger than it was forecasting. But by the start of December I could see where it was leading and I placed NYC in the +2.5 to +5.0 departure range for the month of December based on the P7 composite match plus other custom local climo trends. My best guess for +10 was near International Falls.

I was pointing out in late November ahead of what the Euro was showing that the risks to the late December forecast would be to the warmer side based on its MJO inherent biases which turned out to be correct. The reason for the geographic location of the +10 this month is a blend of warming climate combined with the MJO and El Niño. When the NYC metro went +10 last January it was the interaction of the MJO, La Niña and warming climate. So the ENSO and MJO combos can be guideposts as to where the forecaster puts the +10s on a monthly forecast.

The greater underlying issue is our rapidly warming climate. This has produced the record warming in the Western Pacific which in turn leads to slower and more amplified MJO 4-7 phases. So there were several underlying issues compounding the warmth potential in addition to the oversimplified El Niño means warm December explanations. The reason the source regions were working against us for cold is the combination of all the factors I mentioned above. +10 monthly departures over parts of North America have become more common and just can’t be reduced to saying it’s expected during an El Niño. DFW went +13.2 in the December 2021 La Niña when there was an interaction with the very amplified MJO 6-7 even by RMM chart standards which worked in that case.

The MJO component needed to be anticipated by examining the usual model biases at the longer lead times which was being discussed here back during the fall. Long range guidance like the ECMWF is usually very good at identifying the ENSO input but can’t see the correct MJO phases or amplitude very far in advance. So the model had the stock El Niño ridge over Canada. This was fine for getting the location of the departures correct. But the magnitude of the warmth greatly exceeded the expectations back in late November. The missing piece of the puzzle was the dominant and much warmer MJO 7 composite in the December means rather than the vanilla El Niño composite which is typically much cooler with the ridge axis displaced further NW.

The RMM charts this month really didn’t do the forcing justice near the MJO 7 region. The VP anomalies in that region were some of the strongest on record for the first 3 weeks of December. So it was the record Nino 4s with the MJO action slowing into the circle in 6-7. El Niños usually feature the forcing further to the east. But it was the MJO interaction along with Nino 4s which produced the record warmth across Canada and the Northern Tier.

This was probably the greatest winter surfing event on record around the region.