bluewave

All we need is a slightly stronger transient Southeast Ridge separating the two systems on Sunday for NYC to go from a C-2” to 2-4”type event. New run Old run

The mid-level lapse rates in NJ really mean business.

While the ensembles may be smoothing things out too much, all 3 OP runs try to show a transient Southeast Ridge in 10 days.

My guess is that NYC will see several days with highs over 32° from the 6th to 16th.

10-11 was our last chance to surpass 95-96 when Newark got 60” in only 33 days. But the pattern reversed too quickly after January. We were one of the few spots from DC to Boston that didn’t set a new seasonal snowfall record during the 2010 to 2018 record KU era.

But 2016 was warmer than those 3 years with a better snowfall outcome due to the great STJ pattern.

I hear what you are saying. But storm tracks in January during the last decade have been more important than average temperatures for snow. Provided that the NYC monthly average doesn’t get above 40°. NYC January average temperatures and snowfall since 2015 2024….37.0°….2.3” 2023….43.5°….T 2022….30.3°….15.3” 2021….34.8°….2.1” 2020….39.1°….2.3” 2019…..32.5°….1.1” 2018….31.7°….11.2” 2017….38.0°…7.9” 2016….34.5°…27.9” 2015….29.9°….16.9”

From 69-70 to 92-93 NYC had 12 seasons when the snowfall was within 5” of average. Beginning in 93-94 to 22-23 there were only 3 seasons within 5” or normal. So our seasons have become all or nothing in the last 30 years with most seasons well above or well below average. As the climate continues to warm with these challenging storm tracks for snow, the below average snowfall seasons eventually win out. So unless we see a marked improvement in the cutter, hugger, and suppressed southern stream storm track pattern by 2030, the NYC long term average will eventually drop to below 20”.

Doesn’t look like any -20 departures like we saw back on 12-22 at least through the next two weeks.

Close to the global daily all-time high temperature for December 29th. The previous record for this date was set last year. So the global temperatures continue to exceed expectations.

Continuation of the December and multiyear theme. Long range guidance has been too strong with the 500 mb heights and -EPO near Alaska. So as we get closer models show lower heights there. So if they are beginning to show more of a +EPO long range, then the +EPO could verify even stronger in the longer range. Same way the -EPO forecast verified weaker.

The warmer December than forecast allowed Lander, Wyoming to go +11.3° for December. The extreme winter warmth across parts of the CONUS regions has been unprecedented since 15-16. Before this period, having near to above a +10 monthly departure for a U.S. climate station would be a rare to uncommon event. We can remember the double digit departure months occurring much less frequently in the past. January 2006 in the Upper Midwest and March 2012 come to mind. Now these very high monthly winter departures have been happening yearly with multiple months in the same winter recording such departures. We have had a remarkable 12 winter months across varying ENSO states since December 2015 meeting this criteria for one or more climate stations. It’s even more impressive to see these monthly temperature departures occurring in the warmest climate normals period. Dec…2015….NYC….+13.3 JAN…2017….BTV…..+11.0 FEB….2017….ORD….+10.3 FEB…..2018…ATL….+10.6 FEB….2019…MGM….+10.5 JAN….2020…YAM….+9.8 DEC….2021….DFW….+13.2 JAN….2023….DXR….+12.3 FEB….2023…..SSI…..+9.8 DEC….2023….INL…..+15.8 FEB…..2024….FAR…..+17.5 DEC….2024…..LND…..+11.3

A neg nao would not be an issue with a great STJ pattern like we had in 2016 with the super El Niño. A La Niña dominant Northern Stream makes the 50/50 an issue. On top of the generalized faster Pacific Jet since 18-19.

Most of the time it’s cold enough to snow here in January. Some of our snowiest Januaries were warmer than average. But our big issue since the 18-19 has been the overpowering Northern Stream of the Pacific Jet. So it makes it harder to get heavy snows here with the cutter, hugger, and suppressed Southern Stream storm tracks. I would gladly take a warmer January like 2016 and 2017 if we had a primary benchmark storm track instead with the multiple KU events those years. Hopefully, we can get the fast Pacific flow with so many shortwaves close together to relax enough for at least one 4”+ or 6”+ event in NYC before the +PNA -AO eventually fades. But as we have seen even during some colder intervals this time of year there is no guarantee. Since the suppressed southern stream issue is showing up in the modeling wit the fast Pacific flow with multiple embedded shortwaves plus the 50/50 confluence. This is a situation where a dominant STJ would probably be of more benefit.

Same issue across North America and the entire Northern Hemisphere. https://www.star.nesdis.noaa.gov/smcd/emb/snow/HTML/snow_extent_monitor.html

Same situation as we have seen in recent years with the coldest departures going to our west or south. The delayed freeze-up on Hudson Bay and strong blocking there is keeping nearby Canada very mild. You can see the milder temperatures relative to the means working down into Northern Maine.

Yeah, this would have been a colder than average December in earlier decades since the average is close to 40° these days.

The record warm up near the end of the month dropped the monthly average departure to -0.5. EWR….-0.1 NYC….-1.2 JFK…..+0.9 LGA…-1.0 HPN….-0.3 BDR…..-1.3 ISP…..-0.6 AVG….-0.5

Happy New Year everyone. This was probably the most lightning we have ever seen to ring in the New Year. Very impressive light show here.

This was the lowest anomaly we have ever seen this time of year. The EPS weeklies missed this January pattern from back on December 11th. It had lower heights near Hudson Bay and Greenland and not the very strong blocking we have now. Almost looks like the original runs were defaulting to a coupled look with the strong SPV over Canada. Also notice the long range EPS continuing to show too strong a -EPO with lower heights near Alaska than originally forecast. Also a stronger Pacific Jet lowering heights near that region. https://nsidc.org/sea-ice-today/analyses/sluggish-freeze-warming-north https://sites.google.com/view/arctic-sea-ice/home/nsidc-arctic New forecast EPS forecast from December 11th

13-14 was more centered over the Midwest. 93-94 was one of the last times that Canada was able to load with so much Arctic air. Our best Arctic outbreak around NYC since 94 was during one of our warmest winters in 15-16 on Valentines Day. The key was the solid blocking north of Alaska. So NYC was able to go below 0° which it couldn’t pull off in the much colder 13-14 and 14-15 winters.

The Arctic outbreak in early January looks similar to other ones we have seen during the 2020s. The coldest departures relative to the means go to our west and south. Nearby Canada is still warmer than average with the delayed freeze- up around Hudson Bay. https://sites.google.com/view/arctic-sea-ice/home/nsidc-arctic

We are in track for the greatest AO volatility from October into January with possibly the first +4 October daily reading followed by -4 in January. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.index.b500101.current.ascii

This could be one of our strongest January -AO patterns without a SSW .So maybe the delayed freeze-up around Hudson Bay is giving us an asssit. A very impressive bottom up rather than top down process.

The 7 station December average is currently at -0.9 which will be a little smaller after the 50° warmth today is factored in. EWR…-0.5 NYC….-1.3 JFK…..+0.6 LGA….-1.6 HPN….-0.8 BDR….-1.6 ISP…..-0.9 AVG….-0.9