bluewave

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.

The MJO slowing in 7 this December focused the greatest departures over Canada and the Upper Midwest. It was the stall in 5 during the December 2015 El Niño that gave us the +13.

If we had the Christmas week departures that they are going to have, we would be in the low 70s instead of the 50s.

Yeah, the Northeast is closer to +5 for December and the upper Midwest is around +10.

I know most people off this forum don’t mind the lower heating costs as December has become more like what November used to be. But another December flash flood at the ski resorts so soon after the Christmas 2020 event is very damaging to the ski industry. Plus people don’t want to be cleaning up flooded basements at any time of year and especially near the holidays.

Another top ten warmest month across the region as we have had something like 20 to 30 top ten warmest months to only one coldest month since the 15-16 super El Niño.

All-time December record high temperatures in Newfoundland and Labrador this week.

Who knows what normal means anymore with our snowfall when NYC goes from the snowiest 5 year period to the 7th least snowiest 5 year period in the same 10 year period. Maximum 5-Year Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Value Dates Missing Days Period of record: 1871-01-01 to 2023-12-19 1 209.4 2014-01-01 through 2018-12-31 0 2 205.2 1914-01-01 through 1918-12-31 2 3 204.9 1892-01-01 through 1896-12-31 3 4 204.3 1893-01-01 through 1897-12-31 3 5 202.1 1944-01-01 through 1948-12-31 0 6 199.4 2013-01-01 through 2017-12-31 0 7 197.0 1871-01-01 through 1875-12-31 0 8 193.4 1872-01-01 through 1876-12-31 0 9 193.0 2010-01-01 through 2014-12-31 0 10 191.3 1895-01-01 through 1899-12-31 3 Minimum 5-Year Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Value Dates Missing Days Period of record: 1871-01-01 to 2023-12-19 1 66.1 1928-01-01 through 1932-12-31 0 2 66.2 1927-01-01 through 1931-12-31 0 3 71.9 1951-01-01 through 1955-12-31 0 4 72.2 1950-01-01 through 1954-12-31 0 5 74.8 1988-01-01 through 1992-12-31 0 6 77.0 1949-01-01 through 1953-12-31 0 7 77.7 2019-01-01 through 2023-12-31 12 9 79.4 1997-01-01 through 2001-12-31 1 10 81.8 1973-01-01 through 1977-12-31 0 - 77.7 1971-01-01 through 1975-12-31 0

Pretty wild for Queensland to potentially set the new all-time 12 hr rainfall record during an El Niño when the previous record was during the 71-72 La Niña.

The high temperatures are driving the warm departures for a change so far this month. The +5.1 departure in NYC is an average between a +5.3 max departure and +4.8 min departure. A large portion of the Northern States are +5 or greater.

Yeah, it’s helping to drive the warmth here with the big jet extension.

We have had plenty of hostile patterns in December since 2011, but the snow extent across North America is the lowest in nearly 20 years. https://www.star.nesdis.noaa.gov/smcd/emb/snow/HTML/snow_extent_monitor.html

Most of Arctic air in Eurasia will dump into the Pacific next few weeks and rapidly modify leaving very little Arctic air in the Northern Hemisphere.