bluewave

NYC just experienced its biggest February hourly temperature drop on record. The temperature fell 18° in just one hour. This beats the previous February record which was 10°. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NY_ASOS&zstation=NYC&hours=1&month=feb&dir=cool&_r=t&dpi=100&_fmt=png

Still a +PNA with a trough over the Great Lakes like the GEPS at the end of the run on the 19th.

We are entering a big temperature swings pattern. An earlier high of 57 in NYC is quickly dropping. Cold returns for the weekend before another warm up next week. Then this is followed by another cool down in mid-February.

One of our biggest temperature differences between NYC and the Bronx with 56° in NYC and 37° In the Bronx. Regional Weather Roundup National Weather Service New York NY 700 AM EST FRI FEB 04 2022 Note: "FAIR" indicates few or no clouds below 12,000 feet with no significant weather and/or obstructions to visibility. NYZ071-072-176-178-NJZ106-104-041300- New York City Metro Area CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park LGT RAIN 56 53 90 MISG 29.84F World Trd Ctr NOT AVBL Bronx Lehman C N/A 37 36 93 N9 N/A WCI 31 LaGuardia Arpt LGT RAIN 52 48 86 S7 29.82S Queens College N/A 48 46 93 S14 N/A Kennedy Intl LGT RAIN 48 47 96 S21 29.84F Breezy Point N/A 45 N/A N/A S12 N/A Brooklyn Coll N/A 52 50 93 SE8 N/A Staten Island N/A 57 55 94 S7 N/A Newark/Liberty CLOUDY 55 55 100 S10 29.81F Teterboro LGT RAIN 39 38 96 N10 29.84R FOG WCI 32

90 days is the record in NYC. But we recently made it above 50 days in 2015. Before that it was 1977. Number of Consecutive Days Max Temperature < 50 for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Run Length Ending Date 1 90 1881-02-10 2 77 1969-03-15 3 74 1910-02-26 - 74 1877-01-31 4 69 1905-03-17 5 68 1885-03-26 6 65 1977-02-10 7 63 2015-03-08 8 62 1941-03-02 9 59 1948-02-13 - 59 1883-02-03 10 54 1971-02-11 11 53 1889-03-11 - 53 1884-02-05 12 52 1916-03-24 - 52 1895-02-28 13 51 1907-03-12 - 51 1873-01-15 14 50 1981-02-01 - 50 1927-01-18

I remember light freezing rain starting in Long Beach around 7am in January 1994. It became moderate during the afternoon. Then briefly heavy in the evening before the temperatures went above freezing around 9 pm. Probably the most challenging driving conditions that I have ever experienced. The trees were gorgeous the next day when sun came out.

You might have to find some old news articles. There was another ice storm in January 1978 along the Long Island South Shore . It wasn’t so bad in Long Beach with the temperature around 32°. But there was about .5 to .75 of ice along Sunrise highway were it was 30°. Long Beach had smaller ice storms only around .25 on Valentines Day 2007 and 2-2-11.

Yeah, 1994 was our most impressive ice storm. It seems like we had around .5 to .75 ice build up on the trees. To get those totals we were near 20° at the start of the event. The winds were very light in that storm so there weren’t any power outages in the Long Beach area. I can’t imagine what it would be like to get 3.00 of ice like areas to our north had in January 1998. https://www.weather.gov/media/btv/events/IceStorm1998.pdf This storm had historic impacts across northern New York, northern New England and southeast Canada due to the prolonged duration of the event (both meteorological and recovery period) and the magnitude of ice accretion and precipitation amounts. The most famous meteorological aspect of this storm was the devastating and destructive ice accumulation of more than 3 inches (75mm) in portions of northern New York and southeast Canada, with heavy ice accumulation across northern New England as well. Another major aspect of this storm was the extremely heavy precipitation across the region, including over 5 inches of rain that caused major flooding in portions of western New York.

The -AO block in 93-94 was one of the strongest on record near the pole. That’s why the winter was so cold and snowy with the TPV locking in near Hudson Bay. 02-03 had a -AO from December through January. So the 50/50 low remained stuck in place for PD2 even though it was weeks after the -AO faded.

It’s much easier for the jackpot to be closer to NYC when there is -AO or -NAO. LGA had some of the highest totals with the January 7th event near the tail end of the December -AO pattern. All last winter the jackpots were closer to NYC with the -AO. The snowfall totals were more equitably distributed in the January 2016 event with 30” extending into Queens and the -AO. The Boxing Day blizzard jackpotted around Newark in 2011 with the record -AO. Newark needed the -AO for the 60” in 33 days that winter. NYC got the heaviest totals over 25” with the February 2006 -AO event. The +PNA opens the door to heavy snows, but the -AO or -NAO is needed for NYC to get the heaviest totals relative to the other areas. NYC can get a 50” on the season like 14-15 with just a +PNA and -EPO block. But NYC hasn’t made it to 75” like 95-96 without the -NAO that we had that season. So while NYC can have nice to great snowfall outcomes just on the Pacific blocking, the -AO and -NAO is needed for greatness like a 95-96 in NYC.

That’s a great example of the split forcing pattern. The forcing near the dateline and WPAC is driving that ridge off the West Coast. While the IO convection is trying to pull the trough back from the East Coast. So the model comes to a compromise between the competing areas of tropical covection.

The whole chasing convection and bifurcated low thing was due to the upper low closing off late. So the low tracked further east. The +AO pattern was too progressive. The big snowstorm last February 1st was during a near record -3 to -5 -AO interval. So NYC and Newark were close to the jackpot. JFK got less than half the snowfall the other day than ISP. The 93-94 winter was -AO with a near record block over the pole. +AO more progressive favoring eastern areas -AO allowed low to close of on time with jackpot over NNJ and NYC

This year seems to be confirming what has been past experience with snowfall jackpots. The +PNA opens the door to heavy snowfall events. But NYC and nearby NJ need a -AO and -NAO to have the heaviest totals in their area. Long Island can get the heaviest snowfall with either a +AO or -AO in a +PNA. This was the case in January and with Juno in 2015. KUs can close off late with a +AO due to the lack of a 50/50 and weaker ridging in SE Canada. So eastern sections into New England picked ip the 30”+ totals. Last year we had a near record -AO and Newark and NNJ was the big snowfall leader relative to the local area.

To the extent that January got much colder following near record warmth in December. But the snowfall reversal in January was in a totally different league. January 22 and 15 were the only years that Islip went from under an inch of snow in December to 30”+ in January. The other years with such extreme jumps were El Niño’s bolded below. So this is completely new for a La Niña year. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Season 2006-2007 0.0 1.0 1.0 2003-2004 0.0 19.1 19.1 2001-2002 0.0 3.7 3.7 2018-2019 T 0.9 0.9 2015-2016 T 24.8 24.8 2011-2012 T 3.8 3.8 1999-2000 T 8.3 8.3 1994-1995 T T T 1978-1979 T 6.9 6.9 1974-1975 T 1.8 1.8 1973-1974 T 9.0 9.0 1972-1973 T 1.5 1.5 1971-1972 T 2.1 2.1 1965-1966 T 12.1 12.1 1989-1990 0.2 2.0 2.2 1977-1978 0.2 27.7 27.9 2021-2022 0.3 31.8 32.1 1970-1971 0.3 11.3 11.6 2014-2015 0.4 30.2 30.6 1980-1981 0.5 13.2 13.7 2012-2013 0.6 3.3 3.9

Yeah, we were all waiting on the MJO back in December. But it got stuck in the warm phases longer than forecast due to the record warm pool north of Australia. The magnitude of the shift in January matches some recent years like 14-15 and 15-16. But those were El Niño years which we came to expect dramatic changes after a warm start. This is really the first time a La Niña shifted so much from December record warmth and lack of snow to record snow and colder in January. Now we have an example of this NE PAC blocking pattern during ENSO neutral 14-15, El Niño 14-15, and La Niña in 21-22. So it can occur in varying ENSO states. This makes seasonal forecasting more challenging since this mode can replace or enhance ENSO expectations.

Recent studies have found that the persistent ridge near the West Coast and Hudson Bay TPV pattern is a result of rising WPAC SSTs. https://www.mdpi.com/2073-4433/10/12/793/htm 4. Conclusions The diagnostics undertaken here suggest that the leading mode of the wintertime atmospheric stationary waves in the Northern Hemisphere has undergone a notable change. Since the 1980s, the first leading mode of anomalous winter stationary eddies in the subseasonal timescale has alternated from the PNA to a comparably strong NAWD. Given that EOF describes the variance of individual patterns, the observed increase in the amplitude of NAWD suggests that it may have overtaken the PNA as the more common type of winter variability, with increased influence from western North Pacific SSTs. The CESM large-ensemble simulations forced with increasing greenhouse gas indicate that the NAWD variance will gradually amplify alongside its low-frequency natural variability. This result implies that the subseasonal variation of the atmospheric circulations over North America could continue to be dominated by the NAWD mode, with the potential to sharpen the east–west temperature and precipitation division across North America. Further comparison of EOF1/EOF2 with PNA/NAWD using spatial correlation reveals a pattern change that is consistent among different reanalysis datasets. Analysis of the paleoclimate simulations suggests that NAWD does co-vary with the global temperature variation at centennial timescales: the NAWD variance was weak in the cooler Pleistocene and gradually increased and stabilized in the warmer Holocene. We further examined large-scale forcing of both atmospheric and oceanic origins for the amplified NAWD and found that most of the documented climate indices, which showed a connection to the 2013–2014 extreme winter of North America, are insignificantly correlated with NAWD with the exception of certain oceanic features like the WNP and Niño 4 (Y + 1); these imply that regional SST anomalies in the subtropical West Pacific may provoke teleconnections that affect NAWD. Future examination of the dynamic processes leading to the NAWD amplification should consider the stationary waves maintenance, namely the jet–terrain interactions, tropical and extratropical diabatic heating, and the effect of Arctic amplification.

Yeah, it leads to these dramatic pattern changes over a short period of time like we saw from December to January. Now it looks like the January pattern is repeating in February. So a combination of big weather swings and stuck weather patterns.

Yeah, competing marine heatwaves are becoming the key to understanding these extreme winter patterns. It adds a new level of complexity to seasonal forecasting. So the old La Niña or El Nino based forecasts are becoming less reliable.

There also seems to be some connection to what we had with the Ridiculously Resilient Ridge back in the 2015 El Niño. Notice how close the forcing was this January to 2015. Both years had convection from the CP to WPAC. This was the coldest January since 2015. We also had a blizzard track not far from Juno with the heaviest snows from LI to SE New England. The +PNA and -EPO this January was just a little weaker than January 2015. So it’s possible the models showing more of a +PNA in February may be the pattern lingering from January. Comparison of January 2022 to 2015 with Nino-like forcing from CP to WPAC

The first 30° month in NYC since 15-16. Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Season 2021-2022 43.8 30.3 M 37.1 2020-2021 39.2 34.8 34.2 36.1 2019-2020 38.3 39.1 40.1 39.2 2018-2019 40.1 32.5 36.2 36.3 2017-2018 35.0 31.7 42.0 36.2 2016-2017 38.3 38.0 41.6 39.3 2015-2016 50.8 34.5 37.7 41.0

We are already seeing a model disagreement between the GEFS and the other guidance near the end of the ensemble runs on February 16th. The EPS and GEPS keep the +PNA pattern going. It could be related to the split forcing in the tropics. The convection south of India would normally produce a -PNA in February. But we see the lingering forcing near the Central Pacific which is more Nino-like as was the case in January. Forcing in that area favors a more +PNA in February. So that may be what the EPS and GEPS is picking up on.

There is no set interval between the date of the SSW and local effects for our area. We had a snowstorm on the same day as the one on 1-23-87. But some years it can take up to 3 weeks. So there is no way of trying to game out how long it will take for the influences to reach the troposphere as each event is unique. Plus we don’t know it the super long range EPS is even correct. It’s very difficult to predict these beyond 2 weeks. So if the weeklies turn out to be correct, then it would be quite an accomplishment. https://csl.noaa.gov/groups/csl8/sswcompendium/majorevents.html

Parts of Long Island already have as much snow at the beginning of February as all of last year. Most years since 02-03 were over 30”. This is a first for a 20 year period. The few years that were below average were under 15”. So no years in the middle between more extreme highs and lows. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr May Season Mean 0.0 0.5 5.5 13.2 12.1 6.8 0.3 T 37.3 2021-2022 0.0 T 0.3 31.8 M M M M 32.1 2020-2021 T 0.0 7.5 1.1 24.9 T T 0.0 33.5 2019-2020 0.0 0.1 4.2 2.5 0.0 T T T 6.8 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 0.0 12.8 2017-2018 0.0 T 6.0 22.0 1.4 31.9 4.6 0.0 65.9 2016-2017 T T 3.2 14.0 14.7 7.4 T 0.0 39.3 2015-2016 0.0 0.0 T 24.8 13.2 3.2 0.2 0.0 41.4 2014-2015 0.0 T 0.4 30.2 13.4 19.7 0.0 0.0 63.7 2013-2014 0.0 0.3 8.1 25.2 24.5 5.4 0.2 0.0 63.7 2012-2013 0.0 4.2 0.6 3.3 31.4 7.4 0.0 0.0 46.9 2011-2012 0.3 0.0 T 3.8 0.6 T 0.0 0.0 4.7 2010-2011 0.0 T 14.9 34.4 3.9 2.1 T 0.0 55.3 2009-2010 0.0 0.0 25.3 6.4 21.7 0.4 0.0 0.0 53.8 2008-2009 0.0 T 10.4 8.9 3.3 13.6 T 0.0 36.2 2007-2008 0.0 0.0 2.6 0.8 7.3 T 0.0 0.0 10.7 2006-2007 0.0 T 0.0 1.0 4.2 3.8 T 0.0 9.0 2005-2006 0.0 0.5 7.6 4.7 19.9 3.2 0.1 0.0 36.0 2004-2005 0.0 T 7.0 21.5 17.0 13.3 0.0 0.0 58.8

The remarkable thing is that even our least snowy winters since 09-10 still had record snows. The 11-12 winter had the record snowiest October in NYC. 19-20 tied for the snowiest May with the trace of snow. So every year since 09-10 had a top 10 snowiest month at one of the sites in the OKX forecast zones.

The historic +13.3 departure in December 2015 marked the shift to much warmer winters. This January is only the 5th winter month out of the last 20 with below normal temperatures. The coldest departure month was this January at -3.2 NYC Jan 22….-3.2 Dec 21….+4.7 Feb 21….-1.1 Jan 21….+2.2 Dec 20…+1.7 Feb 20…+4.8 Jan 20….+6.5 Dec 19….+0.8 Feb 19….+0.9 Jan 19….-0.1 Dec 18…+2.6 Feb 18…+6.7 Jan 18….-0.9 Dec 17…..-2.5 Feb 17…..+6.3 Jan 17….+5.4 Dec 16….+0.8 Feb 16….+2.4 Jan 16….+1.9 Dec 15….+13.3