bluewave

The overall size of the troughs has been shrinking. So the record cold in spots like Nebraska had smaller geographic footprint than in the past. These strong -EPO +PNA and -AO patterns in the past had much more extensive cold and larger troughs. If we just isolate those features, then this was our warmest winter of the group which included 02-03, 85-86, 76-77, and 62-63. So those were much colder teleconnections in the past when the 500 mb ridges weren’t crowding out the troughs.

On the day of the strong cutter back in mid-February that produced the record snows from Toronto to Montreal it was more about the -AO linking up with the Southeast Ridge than the -AO being too far north. In the old days we would have done fine with the block extending west to Baffin Island. These days with the faster Pacific flow and record Atlantic SSTs we get more of these Southeast Ridge link ups. From the 1950s into early 1970s even when we had strong -PNAs, there would be a trough over the Eastern U.S. and not a ridge when there was a -AO.

I had several friends in the airline business when I lived in Long Beach. The West End had plenty of flight crews renting apartments close to JFK. It’s a really great lifestyle if you really enjoy traveling and seeing the world.

Yes during February 2021. So this is the first time since the late 1960s without a KU blizzard here during either a La Niña or El Niño February with a -5 -AO. We had our blizzard in February 2021 before the -AO peak. The February 2010 multiple blizzards with that -5 -AO had the amazing STJ pattern. Back during the weak El Niño in February 1978 with that -5 -AO we had the greatest 1970s blizzard. Then the famous Lindsey Snowstorm in February 1969 with that -5 - AO.

I can remember living back in Long Beach in the old days when the Concorde would fly over just after 9am every morning heading into JFK. Now that was really loud. But you got used to it in Long Beach and it was pretty cool.

But not when we have had the -AO dip below -5 in the past.

We had a very strong Southeast Ridge this February which pushed the storm track well to the north. This was the first time a -5 -AO linked up with the Southeast Ridge. So another case of the -AO not delivering for coastal sections like we saw in December 2022 and numerous other times this decade.

I know that. But with these further north storm tracks, even places outside the traditional snow belts can do very well. While past -5 -AOs favored DC to Boston, this was another one that linked up with the Southeast Ridge which has become a regular occurrence in the 2020s. So the heaviest snows got pushed up into Canada instead with this much warmer storm track. But the most impressive records continue to be in the favored lake effect zones like we just saw in Gaylord.

The EPS is correcting warmer now closer to St.Patricks Day as the blocking is linking up with the Southeast Ridge. So we are finally shifting into more of a spring pattern. As the cool downs behind the fronts become weaker and the warm ups stronger. New run Old run

Good to see the Euro and GFS continuing with the first 70° potential next week for the usual warm spots.

The Euro has a strong El Niño Costero next few months but it isn’t able to transition to full basin warming. Still too early to tell what happens due to the spring forecast barrier. Sometimes these Costero events go full basin like we saw in 2023-2024 and other times the signal fades out like in the spring of 2017. Getting a strong enough WWB and OKW is usually the determining factor as to whether the whole basin shifts into El Niño or not.

The lake effect zones have had numerous snowfall records in recent years. So maybe you mean synoptic snows? This 7 year data conforms to what has been happening over the last 30 to 60 years. So you make an error when saying it’s only 7 years. It’s not singling anything out but rather it’s matching the longer term existing trend. From the 60s into the early 90s my area had a cold and stable temperature pattern. So the areas around NYC had mostly mid range snowfall seasons. Very few much above normal and much below normal snowfall. Since the 90s we have shifted to an all or nothing snowfall distribution pattern with hardly any snowfall seasons near the middle of the distribution. So our snowfall has become much more extreme with well below and well above dominating. This 30 year shift has occurred against the backdrop of rapidly warming temperatures. The record snowfall highs from 09-10 to 17-18 and the record lows since 18-19 perfectly conform to this 30 year snowfall distribution shift. In the colder era before the mid 90s, the NYC area could reach the middle range of 19” to 31” seasons without historic KU benchmark NESIS storms. So a colder climate provided more options of reaching this mid range.Obviously, the KU seasons were the ones which finished well above the mean. So NYC Metro and other locations have fewer options of reaching this middle range. Many seasons jumped above this range from 09-10 to 17-18 relying exclusively on a 1 in 100 year phenomenal concentration of Benchmark storms with a significantly higher concentration of NESIS events experienced in the past. So my guess is that relying on a another 9 year run like that is probably a low probability chance of reoccurrence. Now we are left with the current all or nothing pattern where the higher and middle range distributions seeing smaller probabilities. So it’s no surprise when we lost the benchmark tracks for much of the time since 18-19 ,that the region is at the all-time record lows for snowfall. Past lows near this range over 7 year periods were primarily a result of drier conditions and not record warmth. These were followed by numerous 50” + seasons which were easier to come by in a colder climate. So as we continue to warm, both storm tracks and the seasonal background temperature warming provide less opportunities for snow. Having to rely so heavily on just one type of storm track has left us open to repeated well below normal snowfall seasons last 7 years. Since the Great Lakes cutters, I-78 to I-80 hugger tracks, and suppressed Southern Stream lows with the faster Northern Stream of the Pacific had lead to record low snowfall. The data suggests a few ways this could go in the coming years. First, my guess is that the longer term snowfall peaked in 17-18 around NYC .Then 18-19 began the decline that has been expected in a warmer climate reducing snowfall chances. Option one is that the last 7 years continues and represents the new normal for snowfall. Option two is a return to occasional benchmark storm tracks with an uptick in snowfall next several seasons but coming up well short of 09-10 to 17-18. This would be followed by another downtown in the 2030s if it did occur as temperatures continue to warm. Option 3 is a return to the 09-10 to 17-18 benchmark era which I give the smallest chances to.

We will need steady rains in order to come out of this drought which has been going since late last summer. There is higher water demand in the warm season so drought and heat would lower the reservoir levels and lead to water restrictions which haven’t been in effect since 2002. Most people probably don’t want watering restrictions for their lawns. So hopefully we can see a relaxation and not intensification of this drought for much of the US.

It would be good news if the new Euro seasonal wetter pattern into the summer verifies on the update today. But who really knows with these long range rainfall forecasts. One wild card could be how much warming we get in the ENSO regions. https://charts.ecmwf.int/products/seasonal_system5_standard_rain?area=NAME&base_time=202503010000&stats=ensm&valid_time=202504010000

The last 7 snowfall seasons have been the lowest 7 year snowfall combined from Philly up to Boston. It has been a result of the much warmer winters and the warmer storm tracks. Since the 1990s, this region has relied heavily on coastal Noreaster tracks near the 40/70 benchmark to reach average to above average snowfall. In the colder era before the 1990s, there were several seasons reaching average snowfall without big KU NESIS snowstorms. So there were more ways to break even in a colder climate. Since tracks further to the west didn’t draw in the amount of warmth we have experienced with the cutter and hugger tracks over the last 7 seasons. Places like NYC have come to rely exclusively on this benchmark storm track just to approach average last 30 years. So when just one type of storm track which can be a smaller percentage of the total storm tracks essentially shuts off, the outcome has been record low snowfall averages over 7 years. While the region experienced their first average temperature winter in a decade this winter, the storm tracks were still too warm for heavy snows in places like NYC. Since the storm day winter average temperature was 41.0°. So this muted the effect of the 34.8° winter average temperature which was very close to the 1951 to 2010 long term average. This has been the first 7 year period with such low snowfall being the result of warmth. Past 7 year snow droughts were usually the result of drier patterns and not lack of cold for winter average temperatures and storm tracks. In the colder climate we occasionally had dry stretches. So shifting back closer to average snowfall for the remainder of the 2020s will be more of a challenge now since the warmth has continued increasing. Those past record low 7 year stretches all ended with heavy snowfall with NYC seeing upwards of 50” and 60” to over 70”. Such higher totals for especially from Philly to NYC will be a challenge in the much warmer 2020s climate. Boston probably has more leeway to break the snow drought if we see a true benchmark storm track return since they are a colder climate than Philly and NYC. This highlights the challenges of having to rely so much on just one type of storm track for average to above average snowfall. This wasn’t the case in a colder climate for average snowfall seasons around NYC. But getting the big seasons still required the benchmark track. State College is a location that relied heavily on one type of storm track for their heavier snows. The a storm track called Apps or inside runner used to be very common there. These days we see more storms tracking west of the mountains and giving the Great Lakes historic snows. So State College has seen a steady 20 decline in their snowfall over the last 20 years. I am hoping this isn’t a good comparison to benchmark tracks since we are only 7 years in and not 20 years like State College. So it will be interesting to see what happens during the rest of the 2020s. 7 year running average record low snowfall PHI….2025….13.6”…….1992…..14.9”……95-96….65.5”….1955….13.4”……57-58….41.8” NYC…2025….14.9”…...1992…..16.3”…..93-94…53.4”….95-96….73.6”…1976….17.2”…77-78….50.7”…..1956….17.0”….57-58….44.7”…..1932….15.4”….33-34…..52.0” BOS….2025…..26.6”…….1992…..29.9”…..92-93….83.9”….93-94….90.3”….95-96….107.6”……1955….29.9”…..55-56…..60.9”…..56-57….52”

Yeah, this has been a slightly lower 7 year running mean for snowfall than we had in the 70s and 80s.Those were a result of dry patterns and not warm ones like we have been getting since 18-19. So it’s less likely that we see multiple 50”+ seasons next few years to break this drought like those ones did in 77-78, and 93-94, and 95-96. Becoming too warm for heavier snows is a bigger hurdle than overcoming the occasional dry spell in a colder climate. This year was too warm on the days with .25 of precipitation with an average of 41.0°. So the storm tracks made it too warm for much snow this past winter. Other recent winters had both warm storm tracks and average winter temperatures. So the winter average of 34.8° didn’t do us much good since it was mostly on the days without precipitation. JFK and other local stations new record lowest 7 year snow average of 14.5”.

The EPO will be positive with a -PNA so the -AO will just trap seasonal Pacific air underneath. The good news is that we can get some much needed rainfall with the very fast Pacific flow continuing into late March. Hopefully, the dry pattern since last fall will gradually abate by the time we get to the summer.

The EPS only had 40s last Saturday and me made it to the mid-60s. So it has been running a cold bias all winter. These are the 90 day averages so individual days like last Saturday can have much greater bias.

100% of all seasons since the 1990s with average to above average snowfall had benchmark snowstorm tracks. I am using a 19” to 31” range as average for EWR to ISP. If it’s say only 15% of the total storm tracks if it’s that 15% which is 100% critical to our seasonal snowfall reaching average. So remove the 15% and you are 100% guaranteeing a below average snowfall season. So having to just rely on one narrower type of storm track for average to above average snowfall leaves us open to lower totals when that track doesn’t materialize. I not sure of the exact percentage but just using the 15% figure being discussed. In the colder climate from the 60s to early 90s, we could rely on tracks to the west of the benchmark including huggers ,clippers, and inside runners to get to average snowfall in the 19” to 26” range. It was even cold enough at times to get decent front end thumps with cutters since it would take longer to scour out the cold air. But the bigger seasons over 30” had benchmark tracks added to the mix. Now we struggle to get much past 15” in recent years around NYC with cutters, and huggers which are significantly warmer than they used to be. Plus we also lost the clipper snowstorm tracks. This is why we are going to need the benchmark tracks return in coming years for our area to reach average or above average snowfall. And avoid a permanent shift well below 20” as our new norm. The next several years will be telling if we are to avoid extending these 7 year record snowfall lows into 10 years or more.

The good news is that it will be mild Pacific air trapped under the block. So we’ll drop back closer to seasonable temperatures for a time. But not the highs in the low 30s and lows near 20° like we just got.

I agree with what you are saying to some extent with the magnitude of the +PNA coming in significantly higher than we have seen in past cases. This goes to the greater shift we have seen since May 2023 with the record blocking and warmth which has dominated in Canada. It’s quite possible that we are at the beginning of some new type of Pacific shift which we don’t fully understand yet. As global temperatures have greatly exceed past cases of Nino into La Niña transitions. Notice how much warmer Nino 1+2 remained this winter even though we were in La Niña.

I use the 500 mb charts for the teleconnections. We can see the +PNA was from December into January like the past analogs that I mentioned. The 500 mb PNA was solidly negative in February with the deep trough near the Pacific Northwest and Southeast Ridge. Chuck pointed this out earlier the thread. But the much faster Pacific Jet rendered all those teleconnections moot in regard to the snowfall especially closer to my area. So NYC got a mild Pacific zonal flow pattern with a winter average temperature of 41.5° on the days that .25 or more of precipitation fell. We were effectively too warm on the storm days for much snowfall with only 12.9” on the season. It lead to the paradox of the Euro seasonal having a correct snowfall forecast around my area even though it had a warmer forecast than the 34.8° average. So a continuation of the warmer storm tracks and lower snowfall which has dominated since 18-19.

Yeah, we effectively got a mild Pacific zonal flow this winter on the days that .25 of precipitation fell in NYC. Those days averaged 41.5°. Same story since 18-19 with cutters, huggers, and suppressed Southern Stream storm tracks dominating.

Good to see the GFS joining the Euro on 70° potential next week for the warm spots as everyone is ready for spring at this point.

The end result was a very strong La Niña Pacific Jet do to the background Maritime Continent forcing and record WPAC SST warmth. This is why we had such low snowfall despite what used to be favorable teleconnectiins in the past like a-5 daily AO, +PNA, and -EPO. Constant parade of storms cutting through the Great Lakes or hugging the I-95, I80, I-78 corridors. So we effectively got a mild zonal flow on the days which we had the storms negating the colder than recent winter tempersrures.