bluewave

Yes that’s true. All the models except the NAM were too surpassed with the system so the snowfall forecasts from the globals were way too low. We really had an epic run of benchmark storm tracks from 93-94 all the way up to 17-18. Both under -PDO and +PDO regimes. The -PDOs were defined by the cold ring off the West Coast. With the +PDOs by the warm ring. So the Pacific Jet was much weaker during the best seasons for benchmark storm tracks during that era. Since 2018-2019 we have need a new type of -PDO defined more by the warm pool to the east of Japan and south of the Aleutians. This combined with the cold over Siberia leads to a faster Pacific Jet and these three prime storm tracks over the last seven winters leading to the record low snowfall. The last reprieve for us was during January 2022 when a solid MJO 8 lead to a weakening of the Pacific Jet and the snowy benchmark pattern from ACY to ISP and BOS. It was the last time we had both a cold and really snowy month. But it was bookmarked by a very warm December and a milder February and March with little to no snow. I am really hoping we can find some periods in this coming winter and others where we can see at least a brief return to benchmark tracks. But the overall pattern since 2018-2019 has been working against that.

Most storms over the last seven years have been falling into the cutter, I-78 to I-84 hugger and suppressed Southern stream. Strong benchmark storm tracks have been missing. This very strong Northern stream of the Pacific Jet has been leading to these groupings. One group of storms gets suppressed to the south as kicker lows in the fast Pacific flow come into Western North America. This was the case last winter with the big Gulf snowstorm which went OTS to our south instead of coming up the coast. The second group is the Great Lakes cutter like we got in mid-February during the -5 SD Greenland block. The jet was so strong and the SSTs to our east so warm that it forced a Southeast ridge rather then getting a benchmark track. Instead Toronto got the historic snows. Enough room between the shortwaves so one system can really amplify and cut to our west like later this week. That was originally forecast to be a coastal storm. Then the third track is the hugger which can produce some lighter snow events like we got last February. But there was still too much Southeast ridging for NYC Metro so the heaviest totals were to our NW. Plus the there are often too many shortwaves in the fast Pacific flow leading to poor wavelength spacing. It would be great in the coming winters if we can at least see a few very deep benchmark tracks. But the last time we were able to pull this off was in January 2022 and February 2021.

The starting point is when the climate began to warm more rapidly along with the oceans. So one of the predictions made years ago was that we would see an increase in the strongest of hurricanes but not necessarily the total number of storms. Has to do with dueling influences as the oceans reach all time record warmth. Stability can limit the total numbers but lead to the storms that do form being more intense. First, we have seen a record concentration in Cat 5 hurricanes in the last decade due to the warmest SSTs ever observed in the Atlantic and other basins. Second, uneven warming of these basins also lead to stability issues at varying points in the season such as what used to be thought of as the peak from late August into early September. So recently we have seen an early burst of activity followed by a late August into early September lull and followed by unusually late season development. When we get these very warm SSTs at the higher latitudes during mid-summer it has lead to stability issues in the tropics. But later in the session these stability issues have been resolving leading to this record late season activity.

The WPAC to the east of Japan is different from the EPAC since the Kuroshio Current like the Gulf Stream waters are certainly warm enough to cause a feedback process. But the wam blob off the West Coast during the 2010s was the result of the forced pattern emanating in the subtropical or tropical WPAC . So once the fall pattern in 2019 shifted the warm blob easily disappeared. This is why 19-20 wasn’t a repeat of 13-14 like some were speculating about that fall. So more remotely forced. The WPAC warm pool is much more stable and longer lasting since both the forcing and SST feedback are at play for pattern maintenance. This is why the Aleutian ridge and Southeast ridge have become such dominant features over the years.

We probably have to factor the summer drought stress during peak heating into the equation. This was the 4th driest and warmest summer here. Last year the summer was much wetter before the dry conditions last fall. Time Series Summary for NEW HAVEN TWEED AP, CT - Jun through Aug Click column heading to sort ascending, click again to sort descending. 1 1966 4.15 0 2 2022 4.29 0 3 2017 4.76 3 4 2025 4.99 0 Time Series Summary for NEW HAVEN TWEED AP, CT Click column heading to sort ascending, click again to sort descending. 1 2022 75.4 0 2 2024 75.2 0 3 2020 74.9 2 4 2025 74.5 0 5 2010 74.3 0

It’s very challenging to guess ahead of time how vibrant the foliage will be during any given year. Not really noticing colors quite a vivid up here compared to years past here and back on Long Island. The best fall color that I can remember back on Long Island was actually the late very vibrant foliage back in 2007. Went to a friends house in Mt. Sinai for Thanksgiving that year and the colors were gorgeous for that late in the season.

I get it that people on here are eager to see some type of shift with the SST and atmospheric state in the WPAC. But what we we are seeing now is only a reduction from very high summer levels to a still very warm level. It’s primarily a result of the recurving typhoons and unusually strong +WPO for October. Plus the subsurface is still plenty warm. So like after the cooling last winter, it didn’t take long for the surface to warm back up in the following months since the subsurface has so much stored heat energy. This is why the PDO has been fluxuaring between deeply negative states and levels and readings which aren’t as negative. But the orientation of the entire sea and atmospheric state results in the -PDO persisting at varying levels. Even with the decline from the extremely warm surface levels to still very warm, this October has produced one of the strongest East Asian to North Pacific Jets on record for the month of October. So it’s really the gradient between Siberia and the entirety of the Western and Central Pacific Ocean SST warmth.

Snowfall season starting at the higher elevations with some still great fall foliage even in the more northerly spots that are just past the peak.

Even with the +PNA -EPO pattern during January, the coldest departures were displaced further south toward the Mid-Atlantic and Southeast since Canada was so warm.

No it wasn’t prior to 2018-2019. Maybe since you live west of I-95 you are unfamiliar with the coastal areas. We had numerous events prior to 2018-2019 which were all or mostly snow. That mid-October storm track would have been mostly rain or mixed near the coastal plain during the winter. Too many storms to count prior to 2018-2019 which were the opposite.

It’s coming near the tail end of a -NAO period which began around the 15th. Not really sure how to define a classic -NAO since there have been many versions over the years with blocking near Greenland. It’s just that during the 2020s we are finding more ways for higher latitude blocking to merge with the subtropical ridge especially at storm time.

I am using the term early season to describe the activity prior to what is considered the late August into early September traditional peak we used to get more often. Erin went Cat 5 on August 16th which is early in the season for Cat 5 development. The record SSTs are why we haven’t had any really low ACE seasons since 2013 and 2014. This lead some to speculate that the AMO was going to shift colder back then. But instead the Atlantic SSTs reached all warmth over the last decade with the historic run of Cat 4-5 systems.

Yeah, that was an amazing late season snowfall pattern. Islip had 36.5” of snow from 3-7-18 to 4-2-18. But Islip has only had a total of 27.6” during 22-23, 23-24, and 24-25 combined.

Noticing the continuing pattern with these cool downs. The coldest departures will be found more to the south closer to where you live as Canada remains very warm relative to their means. Then we are already seeing a big PAC Jet extension in early November forecasts so expect the temperatures to warm up during the 2nd week of November.

I was talking about coastal sections from NJ out across LI. I agree about a heavy wet snow potential somewhere on the more inland side of that heavy rainfall zone in SE MA. Just a little latitude in a marginal setup makes a big difference.

The flow was ENE here near the coast so it would have pulled in too much warm air at the start. The lack of strong deepening would have meant that the coast couldn’t cool down enough at the tail end of the storm for a significant shift to snow. But interior areas would have done well.

The issue with the last coastal is that it remained strung out with two weaker low centers. So even during the peak of winter it still probably would have been more of a high elevation interior event. Not enough deepening to prevent mixing issues near the coast.

I had my first frost on Saturday morning but was very patchy.

Even before we get to the cold season these strong -NAOs are still finding a way to link up with the Southeast ridge or WAR. The storm for this week was originally forecast to be a coastal storm track. But it has shifted to a warmer cutter track to our west. In the old days a -NAO +PNA would nearly always result in a classic coastal storm track since there wouldn’t have been a Southeast ridge or WAR. New run -NAO linking up with the WAR Old run no WAR

This has been the pattern over the last decade. Early start to the season followed by a lull from late August into early September. Followed by a very strong late September to late October. So very challenging to get a low ACE season anymore with the record Atlantic SSTs and these historic RI and so many Cat 4-5 hurricanes.

It’s really interesting how we also had great 11 year runs for snowfall in December and March also. OCT-NOV 2008 to 2018…DEC 2000 to 2010….MAR 2009 to 2019. Following each of those runs it was like someone shutting off a switch during the respective months. OCT and NOV haven’t featured any early season snows since 2018. Our last historic December snowstorm was Boxing Day in 2010. Interior sections near BGM in 2020 got their historic December snowstorm near 40” since the storm hugged the coast too close near ACY for us to get the really heavy totals. Then the big cutter a week later on Christmas with all the damage and flooding at the ski resorts. Then our least really big March with 30” on Long Island was 2018 and some areas did well in March 2019. Since then coastal sections have had nearly no March snow in the last 6 years.

That was a great run of early season snowfall from 2008 to 2018. The higher elevation event later in October 2008 followed by the historic late October 2011 snowstorm. Then the post Sandy snowstorm in 2012 and the SWFE in November 2018.

What I have been saying is that the faster Northern Stream of the Pacific Jet driven by the gradient formed between the record SSTs over the WPAC and Siberian cold has lead to the dominant cutter, hugger, and suppressed Southern Stream since 2018-2019 producing the record low 7 year snowfall totals along the I -95 corridor. My early guess for this winter is that average DJF temperatures will be warmer than last winter was based on the tropical forcing that we are currently experiencing. I was able to identify the factor last October which lead to the colder winter which I discussed in the main forum. This feature isn’t there this October. But since the snowfall was so low last winter, can’t be sure whether we see something similar again or we get a short term favorable MJO leading to higher snowfall totals than last winter. Since we could beat last winters snowfall totals with a few good storm tracks. But the December 4” rule will probably be in effect again for La Ninas. Nearly all La Niña winters since 1991 with under 4” at places like NYC and Newark in December finished the season below. And all above this level went into snowy seasons. Last December we came in under which lead to my December guess for another below average snowfall season which worked out.

Each event is constrained by the overall pattern and not the other way around.

This has been one of the model forecast error patterns for years now of underestimating the WAR or Southeast ridge in the longer range. It’s what has been happening with such a strong Pacific Jet and near record SST warmth over the Gulf Stream and Atlantic. The models were originally forecasting the main low to be a coastal track to our east. But now the -NAO is linking up with the Greenland block again so the low is cutting to our west. So we haven’t any really deep lows taking a benchmark track since January 2022 during the winters. Even the coastal a few weeks ago were two weaker lows instead of one consolidated one. Our primary storm track since 2018-2019 has been cutter, hugger, and suppressed Southern Stream leading to the record 7 year low snowfall totals along the I-95 corridor. I am hoping one of these winters we can get a great MJO 8 month like January 2022 again with the strong benchmark tracks. But each of the times the MJO is approaching phase 8 it has weakened and reloaded into the warmer phases again. So this will probably be a short term modeling surprise if it happens again and not really seen from weeks out. New run stronger WAR Old run weaker WAR