bluewave

It would be pretty wild if the record Aleutians block actually triggered an El Niño event.

Maybe this first Nino-like WWB and STJ enhanced storm track can be a preview of an El Niño for next winter? But then we’’ll need the WPAC to back off an let it couple. So we’ll see how things go. Brief SOI dip to negative 2 Jan 2022 1011.96 1007.80 -2.11 12.36 10.40 1 Jan 2022 1013.42 1008.00 3.82 12.84 10.62 31 Dec 2021 1014.44 1007.60 16.19 13.07 10.76 30 Dec 2021 1013.61 1006.95 15.26 12.88 10.73 29 Dec 2021 1010.94 1004.90 12.04 12.75 10.68 28 Dec 2021 1009.59 1000.95 25.53 12.29 10.74 27 Dec 2021 1009.20 1000.15 27.66 11.65 10.80 26 Dec 2021 1012.82 1000.10 46.71 11.43 10.90 25 Dec 2021 1015.80 1003.15 46.34 10.90 10.65 Nino-like WWB near Dateline

Wavelength spacing looks like it will be important behind the storm a few days earlier. Then it’s a battle of which ridge is stronger. If the ridge east of New England is stronger then a future run could tuck in a little more. Stronger blocking across the Arctic would continue with runs like today. So several days to go for clarification.

Stretched polar vortex into SE Canada with Arctic outbreak into the region several days after the storm.

Newark nearly caught 95-96 in just 33 days during 10-11. So while wall to wall November to April cold and snow is unlikely in a warmer climate, a shorter period of intense snowfall could eventually rival 95-96. Philly beat 95-96 in a much shorter period in 09-10. Same for Boston beating 95-96 in 2015. Maximum 33-Day Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 61.5 2011-01-27 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1996-04-30 78.4 0 2 1961-04-30 73.5 0 3 2011-04-30 68.2 0

3rd warmest December in NYC with many of the top ranking years since the late 90s. 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 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 11 1994 42.2 0 12 1923 42.0 0 13 2012 41.5 0 14 1996 41.3 0 - 1953 41.3 0 15 1979 41.1 0 16 1956 40.9 0 - 1931 40.9 0 17 1971 40.8 0 18 2014 40.5 0 - 1965 40.5 0 19 1957 40.2 0 20 2018 40.1 0

Happy New Year everyone. After a mild start to the year, the Euro is bringing a very intense polar vortex to SE Canada. This is due to the very strong -EPO and +PNA around day 10. So it will be interesting to track the progress of this Arctic outbreak as we get closer.

A perfect Nov to Apr -NAO /-EPO pattern with a ridge near California. Maybe Walt can comment on what the long range forecasts looked like. I really got interested in longer range forecasting after reading Walt’s great AFD’s out of the Boston NWS office in the late 90s. Probably the greatest long range AFDs in NWS history.

I would consider 95-96 a wall to wall winter. Snowstorms from late November into April and 90.75” at BNL. Even though we got that big flood cutter in late January, the monthly average temperature was below freezing.. So consistent cold and snow from the fall into the spring. BNL https://www.bnl.gov/weather/4cast/MonthlySnowfall.htm 4.5…15.5…23.5…20.0…11.25…16.0…90.75 Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Nov Dec Jan Feb Mar Apr Season 1995-1996 43.6 32.4 30.5 33.8 38.9 52.2 38.6

Hopefully, the EPS holds that 12z look going forward. It has been pretty volatile from run to run in recent days. Just goes to show important the forcing shifting east closer to phase 7-8 will be for our January snowfall potential.

Yeah, nice to see it finally roll east after being stuck for so long around those record SSTs near Australia and New Zealand. That’s why the EPS +PNA is so much better than just a few days ago. Even the CPC commented on the non canonical behavior of the recent forcing. The RMM indices indicate MJO-related convection in Phase 8, but this convection has not followed the canonical eastward propagating evolution of typical MJO events over recent weeks and may be more reflective of other tropical signals besides the MJO. Ensemble mean forecasts of the RMM indices suggest a westward retreat of the signal before weakening into the Week-2 period.

That EPS forecast is starting to look like something from late January 2015. When I made my comment about losing a favorable Atlantic the other day, it was based on the ridge being much further west in the old EPS forecast. That kind of blocking over Western North America could produce a 6”+ snowstorm in NYC even with a very +AO vortex. Old run I commented on ridge further west

The STJ may be getting a Nino-like boost with the current WWB near the dateline.

40° and warmer Decembers have become much more common in recent years.

Several stations will finish 2021 in top 5 warmest years. You can see how many top 10 warmest there have been in recent years. The minimum temperature for the year was also among the warmest on record. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2021 57.9 1 2 2012 57.8 0 3 1990 57.5 0 4 2020 57.3 0 - 2011 57.3 0 5 2016 57.2 0 - 1998 57.2 0 6 2010 57.0 0 - 2006 57.0 0 - 1973 57.0 0 7 1991 56.9 0 8 2002 56.5 0 - 1993 56.5 0 9 2017 56.4 0 10 1999 56.3 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2012 55.2 0 2 1998 55.0 0 3 2020 54.9 0 4 2021 54.7 1 - 2016 54.7 0 5 1999 54.3 0 6 2017 54.2 0 - 2011 54.2 0 - 1991 54.2 0 - 1990 54.2 0 7 2010 54.0 0 8 2006 53.9 0 9 2018 53.7 0 10 2002 53.6 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2002 18 0 2 2021 16 1 3 1949 15 0 - 1937 15 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2021 13 1 - 2020 13 0 - 2006 13 0

The EPS VP anomalies as of the 0z showed more motion to the east. Starts out in phase 6 next week and progresses over to phase 7 during the 2nd week of January. So it’s no surprise there is so much volatility from run to run with the NEPAC pattern.

You can see the models continuing to struggle with the forcing. The GEPS was more in phase 6 and a flatter +PNA. While the GEFS has phase 7 and stronger +PNA ridge. Just goes to show how a few degrees difference of forcing location can have such a big effect on the pattern.

Yeah, that’s exactly what a recent study found. https://www.pnas.org/content/116/11/ However, human evaluation of weather as either normal or abnormal will also be influenced by a range of factors including expectations, memory limitations, and cognitive biases. Here we show that experience of weather in recent years—rather than longer historical periods—determines the climatic baseline against which current weather is evaluated, potentially obscuring public recognition of anthropogenic climate change.

DFW just had their version of 2015 in our area beating the next warmest December by more than 7°. Time Series Summary for Dallas-Fort Worth Area, TX (ThreadEx) - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2021 61.3 2 2 1933 54.0 0 3 2015 53.6 0 4 1970 53.5 0 5 1965 52.8 0

This is the 2nd warmest December so far at Newark and Islip. NYC is sitting in 5th place with a few days to go. You can see how the majority of the top 10 warmest Decembers have occurred since the late 90s. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 49.8 0 2 2021 44.2 2 3 2001 43.5 0 4 2006 43.0 0 5 1982 42.8 0 6 2011 42.5 0 7 1990 42.2 0 8 1998 41.8 0 9 1994 41.4 0 10 1971 41.3 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 48.4 0 2 2021 41.3 2 3 2001 41.2 0 - 1984 41.2 0 4 2006 41.1 0 5 2012 40.5 0 - 2011 40.5 0 6 1982 40.1 0 - 1971 40.1 0 7 1998 40.0 0 8 1990 39.9 0 9 1994 39.7 0 10 2014 39.6 0 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 2001 44.1 0 3 1984 43.7 0 4 2006 43.6 0 5 2021 43.4 2 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

I agree. These marine heatwaves have been interfering with the typical ENSO responses during recent winters. A marine heatwave in the WPAC didn’t allow the El Niño to couple in 18-19. The next year we had the record warm SSTs associated with the record fall IOD. Studies found that this may have contributed to the supercharged polar vortex in the 19-20 winter. Last winter the record off equator SST warmth for a La Niña prevented the expected La Niña response. So using past analogs for winter forecasts hasn’t been working out in this new marine heatwave regime.

This is more than the typical La Niña standing wave. The cat 4 marine heatwave in the area is enhancing the convection near Australia and New Zealand. So it’s no surprise that the models have been trying to decrease the convection in those areas too quickly.

Yeah, the 12z GEPS was the same as the 12 EPS at 360 hrs. Looks like a blend of phase 6 and phase 7 forcing. That’s where the standing wave has been stuck for a while now.

The convection on the 12 EPS 360 forecast is strung out across the phase 6 and 7 regions. 12z 360 hr EPS forecast

I think that you put your finger on it. The 360 hr EPS below is a La Niña phase 6 for January on the Pacific side. So it may be really struggling in where to place the convection from run to run. We probably need to see what it does in the next few runs. Image below courtesy of the New England forum