bluewave

The period starting around the 12th could be our first shot at a coastal development.

3” here just to the east of HVN. It’s nice to be in Southern New England for these gradients. Also one of the thicker fogs over a fresh snowpack since I moved up here.

Yeah, my point was that it was more a blend of forcing influences across the tropics rather than one well defined MJO pattern like we have seen in recent winters. This goes back to my research with the very strong forcing which occurred near the Maritime Continent back in October. The past La Niña cases similarly saw weaker MJO 4-6 activity from December into January with +PNA and -EPO mismatch patterns for La Niña. The opposite was true with weaker MJO 5 October La Niña patterns and then stronger through the winter. So there has been a well defined inverse relationship with the October to winter patterns. We can see the blend of forcing across the tropics from January 1-20. So we didn’t get the coherent MJO 8 response and 30 inches of snow at Islip which occurred in January 2022. The late January forcing near the Maritime Continent was more the La Niña interseasonal forcing shift which occurs closer to the start of February. This is why the Southeast Ridge typically emerges during La Niña Februaries.

If the EPS 500 mb look verifies, then you would probably want to see more coupling than we have seen so far this season. This is why the -AO back in January faded pretty quickly. With coupling we would get more than a 5-7 day window where the gradient can finally sink to our south.

There was no real forcing in the 8-1-2 regions. It was mostly In the 4-5 regions. So the +PNA -EPO -AO Niña mismatch pattern was being driven by something else. But it’s possible that the background forcing in 4-5 may have lead to the unfavorable Pacific Jet response. Since Suffolk got 30 inches of snow with a legit MJO 8 back in January 2022. Notice how much more favorable the forcing was closer to and east of the Dateline in January 2022 than in 2025.

The stratosphere and troposphere have been decoupled this winter. So our fortunes will probably rise or fall on what happens closer to 500mb. Hopefully, the EPS ends up being more correct than the other guidance day 10 to 20.

The MJO hasn’t been driving the pattern this winter. This has been a combination of tropical forcing in multiple regions. So expectations based on past MJO events haven’t worked out.

You want the gradient to drop to our south. Otherwise it’s just a bunch of front end thumps changing to rain and 40s. The EPS had a better look beyond 10 days than the GEFS and GEPS. At least a ridge bridge like over the top the EPS is advertising beyond 10 days could introduce a BM track potential for maybe around 5 days. But the whole mid-February pattern will come down to the EPS scoring a win before the pattern begins relaxing later in the month.

The 5 day window would be the amount of time we could get the gradient to our south for more than just overrunning mixed precipitation events. You want the gradient to our south for a BM track. So when the pattern begins to relax we get a coastal development that takes a BM track. No guarantees yet since the GEFS and GEPS are weaker with the blocking. So we just have to let this play out and see if the Euro score a win with the much stronger blocking.

Hopefully, the EPS can score a win here in mid-February. The GEFS and GEPS aren’t as strong with the blocking. But the EPS verbatim is a very nice look. My guess is that if the EPS is correct we’ll probably get a 5 day window before the pattern relaxes later in February.

So far this has been a -1.2° winter across the area from December 1st through January 31st. Jan 2025 EWR…-1.4° NYC…-2.5° LGA….-2.0° JFK…..-0.2° HPN….-1.6° BDR….-1.3° ISP…...-1.5° AVG…..-1.5° Dec 2024 EWR….-0.1° NYC….-0.9° LGA…..-1.0° JFK…..+0.1° HPN….-1.6° BDR…..-1.3° ISP…….-0.6° AVG….-0.8° AVG through 1-31….-1.2°

1976-1977 was in a class by it self. The late 1970s was the last time the U.S had a top 10 coldest winter. The same for our area also. These days we need strong northerly flow to get closer to 0° like we saw in early February 2023. Back in the 70s to early 90s Canada and the Great Lakes we cold enough so NYC could get to -2° and Newark -8° on westerly flow.

Textbook La Niña progression heading into February. The -EPO ridge pulls back to the west allowing the Southeast Ridge to rebound. So February is in track for our first warmer than average temperature departure month this winter.

Combined effects from climate change. The warmth in the Great Lakes plus Hudson Bay were the result of the record warmth in Eastern Canada. So when you have a strong 500 mb low east of New England circulating air from these relatively milder regions the end result is that the cold over the Northeast gets muted. The colder departures to our south this month tracked from the region west of Hudson Bay which was colder. Plus the extent of Arctic air across the Northern Hemisphere was at a record low this winter. So if we had the amount of cold that was available in past decades, Canada and the Northeast would have been much colder.

The warmer ending to January pushed the local 7 station average up to 30.7° or a -1.8° departure. The last time all 7 stations finished below 30° in January was back in 2014. The most recent January that all 7 stations finished under 26° was back in 2004. Other Januaries averaging under 26° were 1994, 1982, 1981, and 1977. So while we have had a few slightly colder Januaries since the 15-16 super El Niño like 2022 and 2018, the coldest January temperatures and departures have been missing the area. EWR…31.1°…..-1.7° NYC...30.9°….-2.8° LGA….32.0°….-2.4° JFK….32.7°….-0.2° HPN…28.0°….-1.9° BDR…29.9°….-1.5° ISP…..30.1°……-1.8° AVG…30.7°…..-1.8°

There was a 95 inches of snow report from New Haven for the 1779-1780 season. https://www.nps.gov/morr/learn/historyculture/hard-winter-news.htm ALL REPORTS INDICATE THAT THE WINTER OF 1779-80 IS THE WORST WINTER EVER KNOWN IN THE NORTHEAST UNITED STATES David M. Ludlum in his book Early American Winter 1604-1820, in the chapter on “The Hard Winter of 1779-80” writes that it was “the most hard difficult winter….that ever was known by any person living. There has been only one winter in recorded American history during which the waters surrounding New York City have frozen over and remained closed to all navigation for weeks at a time…the Hard Winter of 1780.” According to Ludlum, January 1780 rated as the most persistently cold calendar month in the history of the eastern United States, and “The severity of the 1780 season reached all parts of the colonies. Reports from Maine southward along the seaboard to Georgia, and from Detroit down through the interior waterways to New Orleans, all chronicled tales of deep snow, and widespread suffering.” Ludlum believed that his research definitely showed that the season of 1779-80 in the eastern United States well deserved the name given to it by the people that experienced its effects….The Hard Winter. EYEWITNESS ACCOUNTS SUPPORT THIS BELIEF William Smith (a loyalist living in New York City) records in his diary that on January 16, 1780, people were walking across the frozen Hudson River from New York to Paulus Hook (today Jersey City) New Jersey. A Hessian soldier, Johann Dohla recorded in his diary on January 30, "The North (Hudson) and East rivers are frozen solid. The ice was checked and found to be eighteen feet thick. All ships were frozen in, and it was possible to cross over the North (Hudson) River on foot, riding or driving, without fear." Later, (on February 22) Dohla wrote "Today the North River ice began to break, after having been frozen for nearly seven weeks." A German officer, Major Baurmeister wrote, "The severe winter covered the North River with ice early in January; even where the current of the river is swiftest, the ice was eleven feet thick, in spire of the fact that it is 1800 yards wide between Fort George (today Battery Park, New York City) and Powles Hook." February 1780 seems to have been even colder: On February 10, William Smith mentions in his diary that a few days earlier a "24 Pounder" (that is, a cannon that fired a solid ball weighing 24 pounds - the entire cannon weighed three tons) was rolled across the Hudson River to Paulus Hook (today part of Jersey City, New Jersey.) Smith goes on to say that even a heavy load as this it made no impression on the ice. On the night of February 10th, Smith heard that four to five hundred British cavalry rode their horses across the river. MANY ACCOUNTS MENTION UNPRECEDENTED CONDITIONS A teacher in Yale College (New Haven, Connecticut) recorded approximately twenty days with snowfall, and a total of 95 inches of snow that winter. People walked across the Sound from Stanford, Connecticut to Long Island. Others walked from Rhode Island mainland to Block Island. Chesapeake Bay and the York River in Virginia froze over for the first time since Europeans settled there. Many people mentioned in letters that they could not remember a winter as bad.

Imagine how many posts the January 1780 thread would have had if online weather forums were around in those days.

Similar pattern to December when the cold departures got smaller during the last week of the month. EWR…-1.8 NYC….-2.9 LGA…..-2.4 JFK…..-0.2 HPN….-1.9 BDR….-1.5 ISP……-1.8 AVG….-1.8

I was discussing the +PNA mismatch La Niña potential for December into January back in the La Niña thread during October. The very robust MJO 5 this October I pointed out back in October thread preceded La Niña winters like 2020-2021 and 2017-2018. But at the time I was also highlighted that there were other things about this event that didn’t match past analogs. While we got the -EPO+PNA, and -AO, the Pacific Jet didn’t relax like it did during earlier mismatch La Niña Decembers into January. So we got the lowest snowfall for this type of pattern compared to previous years. The clue I picked up on back in October was the change in tropical forcing from the 22-23 La Niña indicating that the warm MJO phases would be inactive this winter so far. And that has been the case with the recent patterns not matching the typical MJO phase composites. For some reason stronger MJO 5 October activity during La Ninas since 2010 have preceded weaker MJO 5s from December into January. And the La Nina’s with weaker MJO 5s in October followed with stronger MJO 5 into the early and mid winter. Click on top right arrow to read post

Today was a great example of how much models like the Euro have been struggling with all the westerly flow in January. The EPS had a 11 day run of NYC not getting above 32° which was much too cold from the 6th to the 16th. Then had lows near 0° last week around NYC which were around 10° too cold. Same today with the Euro having a high at JFK of 46° which was 9° too cool for the 55° high. This is why the monthly average temperatures came in several degrees above the forecasts from earlier in the month. They should develop a way for AI to fix this cold bias.

2004 was the last time that JFK had a top 10 coldest January. There have been 5 top 10 warmest Januaries since 2002. The last below 0° reading at JFK was January 1985. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. 1 1977 21.9 0 2 2004 24.6 0 3 1968 25.6 0 4 1994 26.3 0 5 1981 26.5 0 6 1982 26.7 0 - 1970 26.7 0 7 2003 27.6 0 - 1961 27.6 0 8 1971 27.9 0 9 1976 28.0 0 10 1957 28.2 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. 1 1985 -2 0 2 1982 -1 0 - 1977 -1 0 3 1994 0 0 - 1968 0 0 4 2004 1 0 5 1976 2 0 6 2019 3 0 - 2014 3 0 - 1957 3 0 7 2018 4 0 - 2000 4 0 - 1997 4 0 - 1988 4 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. 1 2023 41.8 0 2 1950 40.5 0 3 1998 39.6 0 4 1990 39.4 0 5 2006 39.1 0 6 2002 38.9 0 7 2020 38.7 0 8 2017 38.6 0 9 1949 38.1 0 10 1975 37.9 0

Yeah, JFK is up to 55° now. So they won’t be able to finish January below 32° like they did back in 2022. The last really cold January at JFK was in 2004. I can remember Reynolds Channel at the Long Beach bridge nearly frozen all the way across. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. 2025 32.2 3 2024 36.0 0 2023 41.8 0 2022 30.3 0 2021 34.8 0 2020 38.7 0 2019 32.4 0 2018 30.2 0 2017 38.6 0 2016 34.6 0 2015 30.7 0 2014 28.6 0 2013 35.0 0 2012 37.2 0 2011 29.1 0 2010 32.1 0 2009 28.7 0 2008 35.3 0 2007 37.3 0 2006 39.1 0 2005 30.5 0 2004 24.6 0

Would be great to know exactly what the trigger was for the rapid acceleration in global temperatures back in 2023. Since it occurred much sooner than past El Niños that were much stronger and has lingered beyond anything in the past into a La Niña. It may very well be that we have just have experienced some type of nonlinear or threshold event on a global scale.

Westerly flow downsloping winds were much colder in the 1970s than today. Canada was significantly colder back then than they were this month. Plus much of the Great Lakes were frozen over that winter. Not to mention a much larger cold pool across the entire Northern Hemisphere. So the broader source region and geographic extent of the cold is very important. Notice that NYC didn’t get below 10° this month with the westerly flow. From the 1970s to early 1990s NYC could get to -2° with westerly flow. These days NYC needs northerly flow to get down closer to 0° like they did in February 2023 when they reached 3°. It’s no coincidence that February 2016 and January 2004 Arctic outbreaks near 0° around NYC were northerly flow events. This is why I posted early on that the Euro and EPS were way too cold this month here. Remember when the Euro had near 0° around NYC this month. The GFS had upper single digits which was closer to reality. The world was a much colder place in January 1977. So the -EPO +PNA -AO pattern like this month had a tremendous Northern Hemisphere cold pool to work with. That wasn’t the case this time around when the world just experienced its warmest January on record. So these teleconnections were much warmer this month.

What theory are you talking about? The planet has warmed tremendously since the 1970s. So even a roughly similar 500 mb pattern won’t be as cold.