bluewave

These were some of the strongest westerlies since Janaury 1977. So this used to be a much colder pattern. Janaury 1977 was nearly 10° colder on average around the area than this month was. But at least we can brag that we got some version of the Jan 77 analog to repeat in a much warmer fashion.

Tomorrow looks like the kind of westerly flow day that high temperatures and winds can beat expectations with the very steep lapse rates and deep mixed layer. A 45-50 day for temps and wind gusts. This has been the strongest westerly flow January of the 2020s.

It’s been the storm tracks since 18-19 which have been main the issue. The much faster Northern Stream of the Pacific Jet has resulted in the predominant cutter, hugger, and suppressed Southern Stream storm tracks. The KU BM track has been missing much of this time with a brief appearance during 20-21 areawide and more localized in January 22. But January 22 was a little too far east so areas further west missed out. This is why we had some of the lowest snowfall totals on record for a La Niña December into January with a +PNA, -EPO, and -AO pattern this year so far. The faster Northern Stream of the Pacific Jet didn’t relax like it did during past La Niña years with strong +PNAs and -AOs. Now that the 500 mb vortex is relaxing east of New England the Southeast Ridge is returning. So we will lose the suppressed storm track risk and substitute it for a hugger or cutter blend risk of warmer potential at the coast. At best maybe we could put together a smaller or maybe moderate event at some point in February. But it’s not looking like a BM KU which is necessary to get us above 20” is on the horizon. La Nina’s are usually frontloaded by nature. So many times the highest seasonal events would have occurred by February 1st. The big question now is if we will be able to go over 10” on the season. Still too early to tell if that will be the case before the season ends. But it’s not a bad thing to keep some hope going for such an occurrence. Last February actually had a much better storm track pattern for snow than anything we have seen this year so far. Record breaking STJ pattern in mid-February since it was an El Niño which are backloaded by nature. But that was only a one week window and many areas missed that great event in Central NJ. But some areas did very well with a +5 departure. Much better than the -2 to -3 this month. So it comes down to storm tracks since it’s usually cold enough to snow this time of year even during winter months that average closer to 40°. It’s just if you want a 50” season near NYC the winter average needs to be near 32° with great BM KU storm tracks. But this hasn’t happened since 13-14 and 14-15. So this month I would be more concerned with trying to get a better storm track rather than whether we get a +1 departure or something closer to +2 or +3. Since either way it will be cold enough to snow. The most important temperatures are on storm day with the right storm track. March is a different story as we need both good storm tracks and cold enough temperatures for snow. Since even an average March in the low around NYC 40s can be marginal for snow. We had a great run of colder Marches from 2010 to 2018 with cold and great storm tracks. But the Marches in the 2020s so far have featured both too warm to snow and unfavorable stoem tracks. Even with the great -AO in March 2022. So we are going to need a return to KU MB storm tracks next 3-4 years in order to avoid the lowest 10 running means for snowfall that we have ever seen. Absent a big shift, the current 5 year mean near 14” in NYC and surrounding sites will become a 10 year average which has never happened before. Same goes for several coastal sites. The BM KU tracks need to return in a big way in order to avoid the first decade average well under 20”. We don’t have the colder climate of the past which would give us over 20” with frequent small to moderate events which was common before the 90s. Several years didn’t need KUs to get above 20”. All our average to above average seasons since the 90s have required KU events with a 10” or 12” max somewhere between EWR and Eastern Long Island.

It’s why areas most east of the Hudson this month couldn’t come anywhere close the lows from early February 2023 with that impressive northerly flow which avoided the Great Lakes.

High winds plus the record January cloud cover coming off the lakes both worked in tandem to warm the minimum departures. So it’s no surprise that the brief radiational cooling around the 22nd occurred during a relaxation of the flow over the Lakes in conjunction with the snow cover. It’s also true that the stronger winds across the Great Lakes picked up clouds and downsloped into JFK adding enough warmth so JFK only dropped to 13° which was a little warmer than the 12 in December. This was only the 3rd such occurrence of the January minimum not exceeding the December minimum at JFK in 24 years. So this January can make for an interesting study of the highly anomalous temperature pattern in the Northeast relative to areas further south. Northern Maine going +5 with West Virginia at -10 never occurred before in modern times during January. Add in the warmest year on record in Canada and latest freeze-up on Hudson Bay along with record Great Lakes warmth to start the season. And we can’t forget the near record 500 mb vortex east of New England for any January acting has a huge gyre causing the flow to travel down from the Hudson Bay and across the Great Lakes. The rapidly warming climate especially since mid 2023 continues to set records. Monthly Lowest Min Temperature for New York-Kennedy Airport Area, NY (ThreadEx) Click column heading to sort ascending, click again to sort descending. 2024-2025 12 13 12 2023-2024 25 18 18 2022-2023 7 29 7 2021-2022 24 9 9 2020-2021 18 15 15 2019-2020 17 19 17 2018-2019 24 3 3 2017-2018 9 4 4 2016-2017 19 13 13 2015-2016 34 12 12 2014-2015 26 8 8 2013-2014 20 3 3 2012-2013 28 12 12 2011-2012 21 13 13 2010-2011 19 6 6 2009-2010 16 14 14 2008-2009 14 7 7 2007-2008 20 14 14 2006-2007 19 9 9 2005-2006 15 14 14 2004-2005 12 6 6 2003-2004 21 1 1 2002-2003 18 7 7 2001-2002 21 22 21 2000-2001 14 15 14

The ridge emerges in the Southern Plains first than expands eastward over time through the Southeast and eventually Mid-Atlantic and Northeast.

Yeah, the much warmer minimum temperature departures than the maximums across the Northeast this month were very obvious.

Those charts don’t go back that far since they are more geared for modern departures. If we use the 1871-1900 January means for NYC, then this month so far is +0.3° rather than the -3.5° of 1991-2020. But even getting an average January vs the older climo is an accomplishment these days. The last really cold January in NYC was back in 2004. That was the 11th coldest January on record. So even using the 1871-1900 means it was still -5.2°.

You can see how the small cold departure over the area back in December disappears as we go back to the earlier climate normal periods.

The storm track pattern is shifting back to the Great Lakes now that the Southeast Ridge is making a comeback. So warmer storm tracks are now the risk rather than suppression. At least we can use the rainfall which is preferable to a dry suppression pattern.

They began to use 30 year departures as the basis for the climate normals when we were in more of a stable climate regime prior to 1980. This was in the era before the rapid climate warming took off from the 1980s especially into the 2020s. In those days the departures were more aligned with the top 10 coldest and warmest months. So a -3 month now is close to normal for earlier period. No chance any more of a top 10 or even top 20 cold month with such a departure. But a +2 to +3 month can be top 10 or top 15 warmest with ease. This is why portions of the Northeast have had over 50 top 10 warmest months since 2010 to only 1 top 10 coldest. The global temperature monitoring sites use an earlier baseline like 1850 to 1900 and don’t have this issue.

Read my original post that you quoted. The modification west of the Great Lakes is probably more related to the warmth adjacent to that region in Canada. Plus the modification in areas like Minnesota and Wisconsin is obviously less than that experienced here in the Northeast from the maps I posted. So your characterization of the maps is incorrect.

We had several factors in play. Warmest year on record in Canada. With the secondary effects of delaying the freeze-up on Hudson Bay and the Great Lakes. So this lead to the surface temperature departures modifying much more than the 850 mb temperature departures near and to the east of the Great Lakes with the dominant westerly flow. So the core of the cold departures at the surface was significantly smaller than at 850mb.

January 1985 was the last time that I got to experience wind chills close to -30° on the Long Beach Boardwalk. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=46&network=NY_ASOS&zstation=JFK&var=wcht&month=jan&_r=t&dpi=100&_fmt=png

The flow around the block used to be much colder in the Northeast before Canada started getting so warm. The warmer Hudson Bay and Great Lakes are 100% due to Canada coming off its warmest year on record. Plus the 500 mb blocks are getting stronger and warmer leading to areas further north warming faster than to the south.

Cold departures don’t mean what they used to in such a rapidly warming climate. New Brunswick which has a record back to 1893 is currently at 28.6°. That’s a -3.1° departure so far against the warmest 1991-2020 climate normals. It would have been a run of the mill cold month during 1961 to 1990 with a departure around -0.4°. The actual temperature is close to January 2018. Having the 30th coldest January average temperature isn’t that big of a deal. But it feels colder relative to how warm the recent winters have been. Time Series Summary for New Brunswick Area, NJ (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. 1 1977 19.5 0 2 1918 20.2 0 3 1893 21.4 0 4 1912 21.9 0 5 1982 22.2 1 - 1940 22.2 0 6 1970 22.6 0 7 1981 22.7 0 8 1904 22.8 0 9 1994 23.6 2 10 1988 24.0 0 - 1920 24.0 0 11 2004 24.3 0 12 1948 24.4 0 13 1961 25.1 0 14 1945 25.2 0 15 2014 25.5 0 - 1984 25.5 0 16 1971 25.6 0 17 1985 25.9 0 18 1976 26.0 0 19 2003 26.5 0 20 2009 26.7 0 21 1978 26.8 0 22 2011 26.9 0 - 1936 26.9 0 23 1905 27.1 0 24 1925 27.2 0 25 2015 27.4 0 26 1968 27.5 0 27 1957 27.7 0 28 1965 28.1 0 - 1922 28.1 0 - 1895 28.1 0 1996 28.4 1 29 1969 28.5 0 - 1935 28.5 0 - 1914 28.5 0 30 2025 28.6 5 - 2018 28.6 0

The CAA into West Virginia which has been very impressive tracked south of the Great Lakes. So the airmass didn’t travel over the warmer Great Lakes with the much lower ice than normal. Plus Erie which is the closest Lake to them is one of the few with sufficient ice cover. Remember, the Great Lakes warmth is a result of the record warmth in Canada which had their warmest year on record. So it’s a symptom of the overall pattern and not the cause. Same goes for the delayed freeze-up on Hudson Bay. The Northeast being closer to this warmer region to the north is why the cold was muted this month in the Northeast relative to areas to our south. Past instances when West Virginia was so cold in January were significantly colder in the Northeast. This is the first time that parts of Northern Maine are +5 with West Virginia at -10. So this is something new for the Eastern US. In the old days it didn’t matter that the core of the cold went to our south. That PV lobe would have been far more expansive covering the Northeast and Eastern Canada. So as the climate continues to warm, the geographic footprint of these Arctic Outbreaks will continue to shrink. We saw a version of this smaller sized Arctic outbreak in February 2021 and January 2019. Much smaller areas of Arctic cold focusing into a smaller area than Arctic outbreaks of the past.

The reason for the delayed freeze-up on Hudson Bay plus the warmer lakes with less ice this winter is due to the lack of cold up in Canada. So the Northeast being closest to these influences muted the cold here this winter. In the old days Canada and the Northeast would have been much colder. A 7 station -2.6° average against the warmest 30 year climate normals would have been a run of the mill colder January before the 2020s. Same story as recent years with the coldest departures missing to our south and west. Canada warmth especially Hudson Bay and areas east January 2025 December 2024

They did a great job with quality control at Central Park while the NWS was still at 30 Rock into early 1993. The new ASOS was established around 1995 when the NWS was already out at Upton. So the deep shade issues artificially cooling the site didn’t emerge until the 1990s. The site was always open exposure like every other climate station before then. So the temperature and snowfall measurements were always very reliable before the NWS left NYC and they made sure that the there was a proper siting for the sensors. You can see how a spot like New Brunswick doesn’t have the sensors underneath the trees. But in a open clearing like the guidelines specify. 1920 2021 New Brunswick proper siting

It’s an accomplishment these days getting two colder winter months in a row even if the slightly colder December was a result of the much warmer averages. This December would have been warmer than average using 81-10 normals. The last time all of our climate sites had 3 consecutive colder winter months was way back in 02-03. During 09-10 some stations had a warmer January.

Yeah, the warmer flow from Eastern Canada crossing the Great Lakes kept the Northeast much warmer than areas to our south.

I never use the term torch when describing monthly temperature departures. My guess is that the February departure will be warmer than average across the 7 station average. Pretty typical for a Southeast Ridge pattern during February in a La Niña year. It’s a bit early for an exact warm departure number.

The trees are tall enough now close in to the sensors that the site can even get shade during the afternoon without any leaves on the trees.

-2.6° is the average. The NYC site has been consistently running too cold compared to the other stations across the area. So the increased tree growth is probably artificially suppressing the temperatures there during the day in the winter like during the warm season.

The cold has been more focused in other regions as the best we have been able to do for a 7 station average this month has only been -2.6°. It’s just remarkable how the coldest departures have been missing the Northeast since the 15-16 super El Niño. Even with the Southeast Ridge completely suppressed in January. So while I am not sure of the exact departure for February yet, it’s probably a good bet that the 7 station average will be warmer than the departures were in December and January as the Southeast Ridge returns. EWR..-2.7° NYC...-3.8° LGA….-3.3° JFK…..-1.1° HPN….-2.6° BDR….-2.3° ISP…...-2.6° AVG.…-2.6°