bluewave

The first we thing see in early January are the VP anomalies almost going off the scale with the record marine heatwave near 60E. While the MJO composites aren’t a perfect match, my guess is that the shift toward a -PNA week 2 of January is in response to this. A deep trough in the West is close to the MJO 2 El Niño composite. The MJO getting over to 3 would tend to build the ridge again in Canada. But any lingering convection near 60E could hold an undercutting trough in the SW. So we may go to an overlapping composite look for a time before the next step in the MJO becomes better defined.

Bradford, PA is currently at +9.0 and at their 2nd warmest December. Time Series Summary for BRADFORD REGIONAL AIRPORT, PA - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 39.0 0 2 2023 37.9 4 3 2021 36.0 0 4 2012 35.8 0 5 2006 32.9 0 6 1998 32.3 0 7 2001 32.1 0 8 2011 32.0 0 - 1984 32.0 0 9 1982 31.4 0 10 1990 30.7 0

Closer to the higher end of my +2.5 to +5.0 range worked out this month around the area. EWR…+5.4 NYC….+4.5 JFK….+3.5 LGA...+3.4 ISP…..+4.3 FRG….+4.5 HPN….+4.6 BDR….+3.0 HVN….+5.6 DXR….+6.1 POU….+5.1 BDL….+5.6

Warmer than Richmond for the 91-20 climate normals.

NYC just experienced the 3 warmest consecutive winter months on record with all 3 months above 41.0°. This lead to the lowest calendar year snowfall at only 2.3”. It was warmer and less snowy than the Richmond, VA averages. Jan 23…43.5° Feb 23….41.1° Dec 23...44.2° AVG……42.9° Dec 01…44.1° Jan 02…39.9° Feb 02….40.6° AVG…….41.5° Jan 98…40.0° Feb 98….40.6° Dec 98….43.1° AVG………41.2° Time Series Summary for NY CITY CENTRAL PARK, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Total Snowfall Missing Count 1 2023 2.3 6 2 1913 3.4 0 3 1973 5.6 0 4 1901 6.5 2 5 1998 7.5 0 6 1953 7.6 0 7 1931 8.0 0 8 1951 8.8 0 9 2012 9.6 0 10 1997 9.9 0 https://www.weather.gov/media/akq/climateRECORDS/RIC_Climate_Records.pdf Richmond, VA….Jan…38.3°…Feb…41.0°….Dec…41.8°…snowfall….8.8”

NYC currently in 2nd place for warmest December with highs forecast to reach 50° or warmer through Friday. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 50.8 0 2 2023 44.1 6 - 2001 44.1 0 3 2021 43.8 0 4 1984 43.7 0 5 2006 43.6 0 6 2011 43.3 0 7 1998 43.1 0 8 1982 42.7 0 9 1990 42.6 0 10 1891 42.5 0

Action Park was my favorite place to go during the summers in the 1980s. NW NJ is a beautiful area. I wish you the best of luck when you make your move.

We generally don’t do as well following SSWs during El Niños that weren’t already snowy before the event. December 1972 and 2006 only had a trace of snow or less in December like this year. The SSW in December 1965 even happened earlier and that December only had a trace. We can’t really count on a repeat of 15-16 since that was an extreme outlier compared to most other years. https://csl.noaa.gov/groups/csl8/sswcompendium/majorevents.html Seasonal El Niño snowfall in NYC with only a T or less in December 2006-2007….12.4…..SSW…2-24 2015-2016….32.8 1997-1998…..5.5 1994-1995…..11.8 1972-1973…..2.8…..SSW….2-2 1965-1966….21.4….SSW…12-8 1877-1878…..8.1

This period is showing us something we haven’t seen before. While we will eventually see another 1” and 2” in NYC and surrounding stations, this long a streak hasn’t happened before. It definitely seems like a shift began to occur with the super El Niño in 2015. We had a record 8 warmer than average winters in a row since then. This December was another top 10 warmest at our local stations. But the 15-16 to 17-18 winters were still snowy. So it seems like those were still part of the snowier interval which began in 09-10. Then in 18-19 we began a 5 year run with much lower and frequently disappointing snowfall outcomes. This is when the warmer patterns began to overlap with less snowy.

The only periods since 18-19 that the Pacific wasn’t hostile were the 20-21 winter and January 22.

I know. She was one of the most gifted singer-songwriters of the last 30 to 40 years.

But that won’t be because if what happened from January 1st to 15th. El Niños with only a T of snow during December typically haven’t had as much snow as the ones with more December accumulation. We can’t count on an exception like 15-16 to recur again since that was such an extreme event. Seasonal El Niño snowfall in NYC with only a T or less in December 2006-2007….12.4 2015-2016….32.8 1997-1998…..5.5 1994-1995…..11.8 1972-1973…..2.8 1965-1966….21.4 1877-1878…..8.1

A very Merry Christmas and Happy Hanukkah to everyone. This had to be the thickest fog that I have ever driven in during Christmas. It was an interesting ride home over the hills here in Southern CT. I am more accustomed to driving in dense fog on flat surfaces like the Ocean Parkway back on Long Island. But the up and down on hills in the dense fog was pretty wild.

Yeah, I remember. We should develop a custom set of indices based more on 500 mb composites. Several times the CPC raw indices don’t do pattern justice. I know most on here consider it a -PNA when there is a trough in the West even with a ridge over the top in Canada which computes as a +PNA on the CPC site. This was the case last January. I would also develop a custom Southeast ridge index.

I am not too concerned about the next few weeks since this season like most El Niños will be judged on what happens after January 15th.

Most of us will call it a -PNA as long as there is a trough the Western US. But it’s possible we may get a technically +PNA with a ridge over the top in portions of Canada. I have seen many times the official CPC site call it a +PNA when we had a trough in the West due to ridging in Canada.

One of my favorite Irish singers who also left us way too soon. Merry Christmas to everyone.

It has been easier for Newark to reach 50° on Christmas since the super El Niño in 15 than reach 90° on July 4th. Data for December 25 - NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall Snow Depth 2022-12-25 30 14 0.00 0.0 0 2021-12-25 55 38 0.16 0.0 0 2020-12-25 62 28 0.66 0.0 0 2019-12-25 48 27 0.00 0.0 0 2018-12-25 42 29 0.00 0.0 0 2017-12-25 38 28 0.20 0.1 0 2016-12-25 52 34 0.00 0.0 0 2015-12-25 63 54 0.03 0.0 0 Data for July 4 - NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall Snow Depth 2023-07-04 83 74 1.19 0.0 0 2022-07-04 91 64 0.00 0.0 0 2021-07-04 84 64 0.00 0.0 0 2020-07-04 87 70 T 0.0 0 2019-07-04 89 74 0.00 0.0 0 2018-07-04 89 76 T 0.0 0 2017-07-04 88 71 T 0.0 0 2016-07-04 84 62 0.46 0.0 0 2015-07-04 79 70 T 0.0 0

Heavy thunderstorms and low 40s later in the morning to heavy snow and 5-10” in the evening near the coast. CT STAMFORD 5 N COOP 10.0 NY BRONX COOP 9.9 NY YORKTOWN HEIGHTS 1W COOP 9.2 NY DOBBS FERRY-ARDSLEY COOP 9.0 NY OCEANSIDE COOP 8.0 NY ISLIP-LI MACARTHUR AP WBAN 8.0 NJ CHARLOTTEBURG RESERVOIR COOP 7.5 NY MINEOLA COOP 7.2 NY LAGUARDIA AIRPORT WBAN 6.3 NJ ESSEX FELLS SERVICE BLDG COOP 6.0 NY SEA CLIFF COOP 6.0 NJ CANOE BROOK COOP 5.7 NJ WANAQUE RAYMOND DAM COOP 5.5 NY JFK INTERNATIONAL AIRPORT WBAN 5.1 NY NY CITY CENTRAL PARK WBAN 5.0 NJ MIDLAND PARK COOP 5.0

What about the rest of North America? https://globalcryospherewatch.org/state_of_cryo/snow/

Alaska is one the few locations in North America that can do OK on snowfall with an overpowering +EPO pattern.

You are doing a fantastic job. Really beautiful display. Even during the colder era, it didn’t snow that much on Christmas. 2002 was our snowiest Christmas in almost 100 years. But it was a real rarity. Data for December 25 - NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall Snow Depth 1909-12-25 38 31 0.34 7.0 M 1902-12-25 34 25 0.72 6.5 M 2002-12-25 37 31 1.30 5.0 M 1883-12-25 31 28 0.38 5.0 M 1904-12-25 27 21 0.16 3.0 M 1969-12-25 29 14 0.25 2.1 0 1975-12-25 33 17 0.17 0.5 T 1935-12-25 30 17 0.05 0.5 T 1879-12-25 40 21 0.32 0.5 M 1976-12-25 36 23 0.06 0.4 0 1966-12-25 32 23 0.05 0.4 7 1924-12-25 36 15 0.04 0.4 T 1962-12-25 35 24 0.10 0.3 T 1974-12-25 40 34 0.19 0.1 0 1926-12-25 43 34 0.09 0.1 T 1919-12-25 27 16 0.01 0.1 2 1892-12-25 24 18 0.01 0.1 M

We have had an active STJ and NPJ split flow dueling all month.

The main difference these days between El Niños and La Ninas in December is the location of the +10 or greater departures. During El Niños the warmest departures are in the north with the +PNA. They shift to the south during the La Ninas with the -PNA. Getting 3 Decembers since 2015 with any section of the US going higher than +10 is pretty extreme. +10 or greater departure months used to be very rare. The +10 at some stations last January in the Northeast was a 4th month which was during a La Niña. A 5th month was the +10 in the Southeast in February 2018. January 2020 which was neutral came close in some locations.