bluewave

While we have been able to sustain the +PNA as the ridge axis pushes east and pulls back at times, the ridge can’t retrograde enough to keep the EPO negative with such a fast Pacific Jet.

We would all be much better off it they just made the OP runs available to 168 hours and everything beyond that time ensemble means.

But a storm signal doesn’t equal big snowstorm along the coast.

Great example of a long range OP GFS outlier run among its ensemble mean.

Between 09-10 and 17-18 the Pacific Jet was much weaker. So we didn’t get the constant parade of storms cutting through the Great Lakes and hugging the coast that has been dominant since 18-19. When the Pacific Jet was weaker, we could get even get cold storm tracks in warm patterns. Meaning the Pacific was able to relax enough to allow a clean benchmark track with no weak lows over the Lakes. These days even benchmark tracks can have a weak low over the Lakes which warms the airmass too much ahead of the low pressure formation to our Southeast. Now we get warm storm tracks even during shorter cold intervals like we had in early December. Warm up ahead of the storm and cool down behind. The reason the snowfall has been so low in the 2020s is that we are getting both warm winters and warm storm tracks. Much stronger Pacific Jet since 18-19

I just said it that way since the wave break which is initiating the NAO shift is originating near the East Coast.

It could just be something as simple as the much warmer Gulf Stream east of the Carolinas leading to a stronger Western Atlantic Ridge. The big Western Atlantic Ridge amplification last few days with 60s into the Northeast is preceding the NAO rise going forward. Higher heights near the East Coast usually leads to a trough formation several days later near Icekand.When we had the trough near the East Coast in early December heights were higher near Western Europe and Iceland.

Those were the days with extended December cold when we could get the whole month averaging around 32°. Now all our Decembers are in the upper 30s or the 40s. While we did get some real cold before Christmas 2022 with the NYC single digit lows, there was near 60° warmth before and after so the month on average was still 38.5°. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 2022-12-23 58 8 -4.1 2022-12-24 15 7 -25.9 2022-12-25 28 14 -15.7 2022-12-26 29 18 -12.9 2022-12-27 35 29 -4.2 2022-12-28 47 33 4.0 2022-12-29 51 40 9.7 2022-12-30 62 46 18.4 2022-12-31 55 50 17.1

Overall a nice event to start weakening the drought with 1-2 west of NYC and 2-4 east.

It will be interesting to see what happens. My one concern is that the MJO is currently contributing to the pattern rather than running it. We continue to get more of an El Niño influence blending in with the EPAC forcing. While the CFS and EPS have more of a MJO 7 look in early January, the GEFS looks different. So the GEFS doesn’t have a clean MJO signal like the EPS and CFS. Not sure which way it will go at this point since competing influences make the very long range more uncertain. Plus you can see some La Niña influences in the GEFS.

It’s only seasonable since the new 30 year climate normals around NYC are close to 40° in December. Back in the old days seasonable was closer to the mid 30s. We used to get a really cold December around or below freezing once every 5 to 10 years . Now we will make it 14 years without a really cold December.

Looks like the fast Pacific flow continues until further notice. Warm ups ahead of the Great Lakes lows and cool downs behind the storms. This could be a -1 to +1 month that doesn’t get decided + or - until New Year’s Eve.

The WAR was much stronger than forecast back around the start of December. But the Pacific Jet has been very fast also. So the trough couldn’t go negative tilt fast enough for areas west of NYC to get the heavier rains that Long Island is getting. Very northern stream dominant pattern.

So far the stratosphere and troposphere have been decoupled from each other but this can always change down the line. https://bsky.app/profile/drahbutler.bsky.social/post/3lbso7bj5q22r

Tree down in New Hyde Park.

Both the EPS and GEFS have a classic El Niño North American pattern for Christmas with higher temperature departures in Canada than Florida.

The Great Lakes continues to be the place for record snows in recent years.

More like the recent December temperature climatology where the coldest departures relative to the means are in early December and the warmer departures occur mid to late month. This is why we have been getting so many 50s and warmer readings this time of year. But the colder starts to December have prevented the monthly record high from getting challenged of 76° on 12-07-98. Since even in our warmest Decembers like 2015 it’s hard to set a new monthly max later later in the month.

The cold departure from the first week of December continues to get smaller as parts of the area approach record highs in the mid 60s today.

The split nature of the forcing between the WPAC and EPAC along with what you just said may slow the convection closer to Phase 7 in early January. I think that’s why all the extended guidance is showing the colder look then. But the interaction with the EPAC forcing may cause some type of interference or shift after that period.

Yeah, the bottom line when the Nina and Nino influences overlap is a very fast and mild Pacific flow.

Yeah, going from the 2010s to 2020s has been the biggest decadal decline in snowfall that we have seen so far. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.6 4.4 7.1 0.1 T 14.2 2023-2024 0.0 T T 2.3 5.2 T 0.0 7.5 2022-2023 0.0 0.0 T T 2.2 0.1 0.0 2.3 2021-2022 0.0 T 0.2 15.3 2.0 0.4 0.0 17.9 2020-2021 0.0 0.0 10.5 2.1 26.0 T 0.0 38.6 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.3 1.1 5.3 12.9 11.8 6.0 0.6 37.9 2018-2019 0.0 6.4 T 1.1 2.6 10.4 0.0 20.5 2017-2018 0.0 T 7.7 11.2 4.9 11.6 5.5 40.9 2016-2017 0.0 T 3.2 7.9 9.4 9.7 0.0 30.2 2015-2016 0.0 0.0 T 27.9 4.0 0.9 T 32.8 2014-2015 0.0 0.2 1.0 16.9 13.6 18.6 0.0 50.3 2013-2014 0.0 T 8.6 19.7 29.0 0.1 T 57.4 2012-2013 0.0 4.7 0.4 1.5 12.2 7.3 0.0 26.1 2011-2012 2.9 0.0 0.0 4.3 0.2 0.0 0.0 7.4 2010-2011 0.0 T 20.1 36.0 4.8 1.0 T 61.9 2009-2010 0.0 0.0 12.4 2.1 36.9 T 0.0 51.4 Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Mean T 0.0 2.5 7.7 7.8 0.6 T 18.6 2023-2024 0.0 T T 3.1 7.8 0.0 0.0 10.9 2022-2023 0.0 0.0 0.4 T 3.0 1.6 0.0 5.0 2021-2022 0.0 T 0.3 31.8 3.3 1.6 0.0 37.0 2020-2021 T 0.0 7.5 1.1 24.9 T T 33.5 2019-2020 0.0 0.1 4.2 2.5 0.0 T T 6.8 Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 0.9 5.9 16.5 12.8 8.2 0.5 44.8 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 12.8 2017-2018 0.0 T 6.0 22.0 1.4 31.9 4.6 65.9 2016-2017 T T 3.2 14.0 14.7 7.4 T 39.3 2015-2016 0.0 0.0 T 24.8 13.2 3.2 0.2 41.4 2014-2015 0.0 T 0.4 30.2 13.4 19.7 0.0 63.7 2013-2014 0.0 0.3 8.1 25.2 24.5 5.4 0.2 63.7 2012-2013 0.0 4.2 0.6 3.3 31.4 7.4 0.0 46.9 2011-2012 0.3 0.0 T 3.8 0.6 T 0.0 4.7 2010-2011 0.0 T 14.9 34.4 3.9 2.1 T 55.3 2009-2010 0.0 0.0 25.3 6.4 21.7 0.4 0.0 53.8 Monthly Total Snowfall for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean 0.9 T 5.2 12.2 7.0 0.6 0.2 26.1 2023-2024 0.0 T 0.2 9.0 0.5 T 0.1 9.8 2022-2023 0.0 T 1.0 6.9 3.6 0.9 0.0 12.4 2021-2022 0.0 T 0.4 36.2 15.3 2.1 T 54.0 2020-2021 4.3 T 13.0 5.8 15.3 0.1 0.1 38.6 2019-2020 0.0 T 11.5 3.1 0.5 T 0.7 15.8 Monthly Total Snowfall for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean 0.1 0.3 6.9 15.8 20.5 8.5 1.0 53.0 2018-2019 0.0 0.1 0.1 2.1 11.6 13.5 T 27.4 2017-2018 0.0 T 9.2 17.8 8.3 23.3 1.3 59.9 2016-2017 0.0 T 5.9 8.9 21.5 10.1 1.2 47.6 2015-2016 T 0.0 0.9 9.5 15.0 4.1 6.6 36.1 2014-2015 0.0 2.6 0.3 34.3 64.8 8.6 T 110.6 2013-2014 0.0 T 11.7 21.8 22.9 2.2 0.3 58.9 2012-2013 0.0 0.4 3.4 5.0 34.0 20.6 T 63.4 2011-2012 1.0 T T 6.8 0.9 0.6 0.0 9.3 2010-2011 0.0 T 22.0 38.3 18.5 1.3 0.9 81.0 2009-2010 0.1 0.0 15.2 13.2 7.0 0.2 0.0 35.7 Monthly Total Snowfall for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean T T 1.3 4.7 3.6 0.1 0.0 9.7 2023-2024 0.0 T T 8.0 3.2 0.0 0.0 11.2 2022-2023 T 0.0 T T 0.3 T 0.0 0.3 2021-2022 0.0 0.0 T 12.1 0.4 0.4 0.0 12.9 2020-2021 0.0 0.0 6.6 3.0 14.3 0.0 0.0 23.9 2019-2020 0.0 T 0.1 0.2 T 0.0 0.0 0.3 Monthly Total Snowfall for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean 0.0 0.4 5.8 10.1 10.8 4.9 0.0 31.9 2018-2019 0.0 3.6 0.3 2.6 6.6 4.0 0.0 17.1 2017-2018 0.0 0.0 8.6 4.6 1.4 15.2 T 29.8 2016-2017 0.0 T 0.3 5.7 2.0 7.0 0.0 15.0 2015-2016 0.0 0.0 0.0 22.9 3.3 1.0 0.3 27.5 2014-2015 0.0 T 0.1 4.3 10.6 12.0 T 27.0 2013-2014 0.0 T 11.2 25.9 22.4 8.5 T 68.0 2012-2013 0.0 T 0.4 3.9 2.7 1.3 0.0 8.3 2011-2012 0.3 0.0 0.0 2.5 1.2 T 0.0 4.0 2010-2011 0.0 T 12.7 25.2 6.1 T T 44.0 2009-2010 0.0 0.0 24.1 3.1 51.5 T 0.0 78.7

Yeah, it looks like we are currently on the more Nino-like side of the long range Euro 3.4 plumes.

The warm spots in NJ tomorrow could make it to the mid 60s.

Plenty of extremes in this pattern with the potential to approach December record high pressure near 1048mb in New England.