bluewave

I think you are mistaking the description of the pattern as complaints. We were bound to have a colder than normal winter eventually after 9 warmer to record warm winters. Even the summers had 3 colder ones out of the last 15. So 12 warmer summers out of 15 is less impressive than 9 out of 10 warmer than average winters.

This has been one of those cases where the 500mb anomalies have varied from the CPC official PNA index. Most of us on this forum would consider it a -PNA pattern when there is a deep trough sitting over Seattle. It really pumped the Southeast Ridge forcing the gradient further north than NYC wanted to see.

Tell that to New Orleans.

The block is very close to where it was for the other 15 times when the -AO reached -4.8 and lower going back to 1969. So it’s not too far north. The greatest difference is that there was no Southeast Ridge in the other dates. So suppression would have been a risk in the old days and not an intense cutter. 15 date composite since 1969 with -AO of -4.8 or lower

This weekend will be our first cutter dropping under 970 mb with a -5 -AO. So the Southeast Ridge got so strong that it prevented the low from sliding to our south like in the past. Should at least be gusts over 50 mph and possibly 60 mph by Monday. Near record 5.5 sigma 500 mb block around Greenland

This is only the 2nd time since 1950 that NYC translated such a low seasonal snowfall total by 02-12 into 20 to 25 days of 1” snowcover. This extension of 12.0” to 21 days has been very impressive. Only rivaled by 80-81 which had 21 days with 10.8”. But 80-81 had a 4.9” event in January while the biggest snow this season to date in NYC has been only 3.0”. So a great job of making so many small snow events last so long on the ground. 2-12-25……21 days..….12.0” 2-12-21……20 days…..33.8” 2-12-15……24 days…..23.5” 2-12-09……21 days…..19.3” 2-12-05….. 20 days…..18.3” 2-12-01…….21 days…..25.4” 2-12-88…….25 days….18.5” 2-12-85…….22 days…..23.9” 2-12-81……..21 days …..10.8” 2-12-78…….21 days……38.6” 2-12-65……22 days……18.8” 2–12-58……22 days……20.8”

May 2020 which tied the all-time heaviest late season snowfall following a string of long range model forecast snowstorms that didn’t work out. That was our latest record snowfall following a disappointing winter when models kept advertising the big one in the long range. Spots had more snow in May than in February that year.

All the past 6 year snowfall period slumps across our local stations occurred in a colder era. So it was easier to achieve near to above 50” snowfall to break the droughts. But we haven’t been cold enough since the 15-16 super El Niño for such high snowfall totals in NYC. Even this winter being colder than the last several have run into p-type issues near the coast. So combined with the less favorable tracks and not having enough cold ahead of the storms will be challenging to get enough cold next 3 winters and an active BM storm track to reach 50” near NYC. Remember even in 20-21 NYC couldn’t make it to 50” due to mixing issues and warmth around some of the storm tracks. In a colder climate that would have been an easy 50” year. So the next 3 winters will decide if the 6 year slump through 23-24 will become a 10 year one when this season ends and becomes the 7th year in the series.

The significant metric at JFK has been the 6 year running mean snowfall from 18-19 to 23-24. It was near the bottom of the list since they started keeping snowfall records there. That’s why the period around the 20th and the next few years are so important. Past instances with similar 6 season slumps all experienced big rebounds in the following years. In fact the reason the 6 year slumps didn’t become 10 year slumps near or under 15”was there there was a quick rebound to near 50” in the following seasons. So we need a major snowstorm around the 20th and a near 50” season next few years to turn things around. But it will a big challenge to expect repeats of 76-77, 77-78, 93-94, 95-96, 02-03, 03-04, and 04-05 in the much warmer mid to late 2020s climate. I will update the new 7 year running mean once this winter ends. Then we’ll have the next 3 seasons to try and avoid the lowest 10 year running mean of 18.0” set in 1993. Lowest 6 year snowfall means JFK 2024….14.3” 2002…13.0” 1993….14.7” 1975….14.7”

I think you guys missed the point of my post within the specific time period of this month so far. The majority of the storms this month had the mixing line near NYC with Southeast Ridge gradient. The storm which just produced the heaviest snows to our south came behind a recent storm which briefly shifted the overrunning gradient zone a little further south. It was a weaker low which couldn’t gain much latitude. The next few much stronger storms will come north again through the weekend eventually pushing the gradient even further north. So this has been a very consistent pattern this month. The storm this weekend will rapidly deepen and drive the gradient down into the mid-Atlantic next week. Then we have another low coming out of the Southeast around the 20th that will be in a tug of war between the tendency of the Southeast Ridge to amplify and the 50/50 low to suppress. We would like to see the low find the benchmark for once this winter before this pattern relaxes later in the month. But we have seen this cutter, hugger, and suppressed Southern Stream storm track play out time and time again since 18-19. So we probably shouldn’t get the hopes up too high for the 20th due to the difficulty of getting a coastal storm just in the right spot near the benchmark. The very fast Northern Stream of the Pacific Jet seems to be driving this persistent storm track pattern. Maybe we can see at least some brief relaxation of this pattern before this winter comes to a close. January was all about suppression with the very strong Northern Stream and near record 50/50 low to our east. It would have been a much better pattern with an undercutting STJ and El Niño as the storm track would probably have been further north with the typical STJ orientation. Then the hugger track has dominated this month with the one suppressed storm near DC last few days.

I moved up to the CT Shoreline near the end of the summer in 2023. The winters are a little colder here with better radiational cooling than the LI South Shore. Plus I still get a nice sea breeze during the summer without too many 90° days.

Yeah, gradient patterns tend to shift further north with heaviest snow totals than models expect around our area especially when there is no strong 50/50 low and confluence. The opposite was true in January when we had the record strong 50/50 low nearby. So the snowfall initially forecast over the Northeast especially on some OP GFS runs went to our south. The model error patterns have been highly predictable.

We don’t live in DC.

Still too high but better than some of the OP GFS runs.

Too much of a cold bias in our area for the EPS snow mean in early February as the mixing line usually verifies further north with gradient patterns.

It’s the lowest seasonal snowfall through 2-12 in over 30 years with an average temperature so far under 35.0°.

This may be the first winter in NYC with 20 days of 1” snowcover and no days of 4” snowcover if we can’t put together a 4”+ event before the season ends.

The amplitude and volatility of the AO, NAO, and other 500 mb patterns has been increasing between deeper lows and higher highs closer together. As the ocean and atmosphere warm the 500mb patterns, jet stream, and storm tracks become more erratic. So we get these odd pairings of features of the like the Southeast Ridge merging with Greenland Blocks which didn’t used to happen in the way we have been seeing in the 2020s.

It’s linking up with the Southeast Ridge which didn’t used to happen with -AOs near -5.

Interesting split with the EPAC going into El Niño mode while the La Niña remains entrenched in the CPAC.

I believe this weekend will be our first cutter under 980mb so close to nearly a -5 -AO. We were talking about blizzards with the -5 -AOs in February 2021, 2010, 1978, and 1969. So the Pacific Jet and Southeast Ridge continue do new things in the 2020s.

The Northern Stream of the Pacific Jet has been unusually fast across the Western Into the Central US so far this month. Pretty much the opposite of what you want to see for a KU event. If this was an El Niño with a STJ a little further south, then we would probably be looking at a 30” February with the blocking. But past La Ninas usually had the Northern Stream weaken with this type blocking. This fast Northern Stream flow leaves more room for cutters, huggers, and suppressed Southern Stream storm track solutions. So we’ll need to see some relaxation of this jet before the blocking fades later this month in order to get at least one heavy snowfall event closer to the coast.

This is the extremely fast and active Pacific Jet loaded with individual shortwaves.

NYC is going to need at least one big 6-12” event before this pattern relaxes near the end of the month in order to make a run on 24” to 25” this season.

What happened since the 1990s was that a greater percentage of snowfall was coming in bigger events. So this masked the decline in the years when we didn’t get big KU events. In a colder and more stable climate we had a wider distribution of snowfall types including smaller, moderate, and major. The data suggests that we aren’t headed back to a 1961 1991 regime with the long term average in the 20s. But a new regime over the next 30 years of under 20 “ since the climate has warmed so much since then From 18-19 to 23-24 NYC only averaged around 15” due to the record warmth and lack of KU events. This season is an interesting case so far. Past cases of this amount of cold and similar long wave 500mb patterns have produced 35” to 50” snowfall seasons for NYC. But the overpowering Pacific Jet has lead to much less so far this season. That wasn’t present with past similar patterns. Going forward my contention has been that NYC will need a heavier snowfall event before this pattern relaxes in late February in order to go over 20”. We need the storm around the 20th to avoid the cutter, hugger, and suppressed Southern Stream storm track pattern which has dominated since 18-19. But we have seen how fast modeled patterns beyond 120hrs have shifted this season to something less favorable than the models were initially showing. So I will say it’s possible we could eventually score a heavier snowstorm around NYC before the end of February boosting the seasonal snow closer to the 24-25” range. But it’s not a guaranteed outcome since it too far out and we have seen how the longer range has disappointed this season so far.