bluewave

I would rather have a warmer winter like 15-16 through this point with a widespread 20-30” snowstorm than the seasonable temperatures and the struggle for more than a few inches of snow at a time of this winter so far.

This year is definitely going against past La Ninas with a +PNA December into January with -AO intervals since the 1990s. It’s the lowest snowfall across the coastal areas for any of those years through January 19th. So the lack of BM KU storms so far this winter is something new with La Ninas with +PNAs and -AO intervals since the 90s. All the other years had a Northern Stream of the Pacific Jet which was much weaker than this year so far allowing better snowfall. +PNA La Niña Decembers into January at times with -AOs intervals snowfall through January 19th 2025….NYC….5.8”…..ISP….4.8” 2021….NYC…..10.5”….ISP….7.5” 2018….NYC….17.9”…..ISP….22.0” 2006…NYC…..11.7”….ISP….12.8” 2001….NYC…..15.2”…ISP….16.0” 1996….NYC…..36.9”…ISP..44.4”

It seems like something changed with Euro and EPS after one of the updates in 2014 and 2015. The Euro and EPS were spot on from 7-8 days out with Hurricane Sandy in 2012. It was the first model to jump on Nemo in February 2013 around 5 days out. Then the high profile storm track error with the blizzard in January 2015 when it was too far NW. This was followed by the January 2016 blizzard forecast from a day out which had the heaviest snowfall axis to our south instead of across the NYC Metro which verified. So it was too suppressed. More often than not in recent years the longer range bias with tracks near the coast has been suppression. It would be great if we could generate a track error database for every East Coast low from each of the models like is done by the NHC with tropical cyclone model track errors. Since the headline model skill scores we see on the various sites don’t specifically have an East Coast storm system statistics. Even in the older era back in the 90s, I believe the Euro was first to have a closer to correct idea with March 1993 and January 1996. While all the models missed the early rapid deepening in the Gulf in March 93, I believe the Euro was closer on the track than the old AVN MRF. it also had January 96 more defined and further north than the AVN MRF which was too suppressed. So I am not sure what happened to the Euro and EPS as the animation below from February 2021 seems to have become the norm for that model at times in recent years.

3 mid range 20s years from 69-70 to 73-74 with none since 19-20.

The sample size of the shift in snowfall distribution in NYC is 60 years long. NYC had 18 seasons with a mid range snowfall from 19” to 30” from 63-64 to 92-93. From 93-94 to 23-24 NYC only had only 4 of these mid range seasons. Nearly all of the seasons since the 90s have been dominated by well above and well below normal snowfall. The last 6 years matches this pattern which was established in 93-94 with only one season in the 19-30” range which was common back in the 63-64 era. My guess on why this is happening is that it’s probably a function of the warming the climate has experienced. From 63-64 to 92-93 we were in much more of a stable climate with significantly colder winters. Our storms were a mix of larger KUs over 10” and 12”,moderate 3-6 or 4-8” type events, and small 1-3” to 2-4” type events. So more balanced snowfall seasons toward a mid range and fewer very high and very low extremes. Since 93-94 our snowfall has become dominated by seasons with numerous KUs where someone around NYC Metro would regularly get a 10” or 12” event from near EWR out to Eastern LI. The seasons when these KUs didn’t appear were mostly below to well below average. Over this period we have experienced the greatest winter warming in modern times. 09-10 to 17-18 represented the greatest era for NESIS KU snowstorms. So it’s no coincidence 15-16 was the first winter with a new heaviest snowstorm on record in NYC and a +13 temperature month along with a subzero low. So volatility has increased along with this warming. The big question going forward is if this most recent shift since 18-19 to cutter, hugger, and suppressed southern stream storm tracks will continue. On that point I agree with you that a 6 year period is too small a sample size to make any conclusions about storm tracks in the future. It’s possible that benchmark KU tracks could make a return. But expecting a 09-10 to 17-18 sustained high rate of KUs may be a challenge. So I stand by my observation from the long term data that a return to KU benchmark snowstorm tracks will be a prerequisite for NYC and other coastal areas to get the snowfall average back above 20” for the 2020s and the future decades. Since we don’t have the more cold and stable climate when we could rely on small to moderate events only at times to get something closer to a long term midrange somewhere in the 20s for snowfall.

The current climate is much warmer than 1970-1999. So coastal areas near NYC can’t get over 20” on the season anymore without a KU. We had numerous seasons during that era around NYC Metro without a KU and 20”+ snowfall. Since there were numerous smaller to moderate events when the temperatures were less marginal for snow. Since the 1990s we have been depending on much larger snowstorms for our seasonal snowfall. So the epic 2010-2018 KU snowfall era was masking the warming pattern. If we can’t get back to more regular KU tracks like we had from 2010 to 2018, then the new seasonal snowfall from EWR out to ISP will be under 20” like it has been in the 2020s so far.

Yeah, these cuttter, hugger, and suppressed southern stream storm tracks have really dominated since 18-19. Leaves very little room for a big KU to rapidly deepen out near the benchmark. The one exception was 20-21 for NYC into NJ and 22 which favored points east of NYC. That’s why I continue to stand by my observation that for NYC to get to 25” or greater on any season they will need to see the BM KU storm track return. Since we aren’t cold enough to get to average with a collection of small to moderate events like was the case during several years in the 1970s and 1980s. It was amazing how many historic BM KUs we had from 09-10 to 17-18.

Nice little event here on the CT Shoreline with 2” just east of HVN.

Yeah, we are seeing a continuation into 2025 of this accelerated warming.

February is the one month with La Ninas when it becomes a challenge to subdue the tendency for more of a Southeast Ridge. Even during the much colder era in the 70s and 80s this was the case. So we need to do the best we can the rest of this month before that starts becoming a factor.

We definitely want to hold onto more of the blocking into Northern Greenland like the EPS had yesterday. New run Old run was better

Good to see the STJ finally become more dominant this winter in the split flow pattern.

Maybe the models backing off a little bit on the Arctic press close to the coast will leave us some room this week for a GFS CMC blend for some follow up snows Tuesday through Friday.

The was actually the strongest 50/50 low at 500mb on record going back to 1950 just to the east of New England in early to mid-January. It finally relaxed enough and we are getting the storm today into tonight. Closer to a gradient pattern which we really haven’t seen in a while.

The RGEM usually moves in step with what the GEM global does.

Why?

The Euro is actually a little further west than the CMC at 0z. The CMC has 6”+ and Euro 4”+ jackpot along those favored North Shore areas in Northern Nassau and NW Suffolk. The SPC HREF has a 6”+ potential in these areas also.

Yeah, thats why I see more and more people with those little booties for their dogs.

Yeah, the most anomalous cold and snow relative to the means are south of us this month.

At least we haven’t had any major ice storms recently which were more common from the 70s into early 90s. The last more significant ones I remember from LB were February 07 and 11. But nothing like the ice storms in Jan 78 and 94.

Yeah, there are going to have to heavily treat all the surfaces with the falling temperatures during and after the storm. In recent years the trucks driving on the major roads have kicked up mini dust storms with all the salt at times. But it’s much more preferable to an untreated flash freeze like we got In January 1986.

If you thought all the salt on the roads was bad recently just wait until the 4”+ in many spots freezes solid tomorrow night with rapidly falling temps into the teens.

December 88 had that great Norlun through Suffolk into CT and 90-91 had several moderate events. Monthly Data for December 1988 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. NY PATCHOGUE 2 N COOP 11.0 NY ISLIP-LI MACARTHUR AP WBAN 10.4 CT MOUNT CARMEL COOP 8.0 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 7.5 CT STAMFORD 5 N COOP 7.0 NY SETAUKET STRONG COOP 7.0 NY DIX HILLS COOP 6.5

We still got a bunch of these moderate events the 70s and 80s. But the period in the late 90s was particularly lacking. The March 99 wet snowstorm that broke all those sycamore branches in Long Beach was the best of that era.

While it was still a bit suppressed, not nearly as much as the regular Euro.