bluewave

Steady light snow here in SW Suffolk with a light dusting on the ground.

This winter has probably been the most Nino-like moderate La Niña that we have ever seen. The +PNA for much of the winter has been classic El Niño. The warmer to colder and snowier progression by later in the winter is also El Niño. The -5 AO AO drop this February only occurred in the past during El Niño winters. Funny how the last two El Niño winters in 18-19 and 19-20 had more Niña-like patterns. So something is going on that is altering the expected ENSO response during the last three winters. Probably related to the anomalous warm SST blobs that have popped up all around the globe. The location of marine heatwaves need to be taken into account. But the interactions may be beyond what seasonal forecasts can resolve. The most reliable relationship between snowy winters and the -AO has worked out nicely this winter or us . February -5 AO readings and ENSO 2021.....-1.2 2010.....+1.6 1978.....+0.8 1969.....+1.1

This has to one of the most backloaded February La Ninas for snow and cold across the US that we have ever seen. Gives new meaning to competing winter influences. Makes it very difficult to produce seasonal forecasts during the fall based solely on ENSO and past analogs. It’s the third consecutive winter that forecasts went against ENSO expectations. Even though 15-16, 16-17, and 17-18 were extreme winters for their weather swings, at least they retained the El Niño and La Niña expected progressions.

This year really takes the prize for snow extent volatility. We went from record highs in October to record lows and now we are on top again. Also interesting how a version of the October pattern repeated in February. https://www.star.nesdis.noaa.gov/smcd/emb/snow/HTML/snow_extent_plots.html

Upton has had 11 years reach 40”+ since 2003 and 9 years reach 50”+. 2002 2003 0 2 11.5 5.8 31.8 5.5 5.5 62.1 2003 2004 0 0 25 22 2.2 11 0 60.2 2004 2005 0 0.5 13 29 20 16 0 78.5 2005 2006 0 1.5 7 4 14 4 0 30.5 2006 2007 0 0 Trace 0.5 3.5 5.5 0 9.5 2007 2008 0 Trace 3 0.5 7 1 0 11.5 2008 2009 0 Trace 10.9 12.1 5.2 14.8 0 43 2009 2010 0 0 26.3 12.7 28.4 0.4 0 67.8 2010 2011 0 0 19.8 35.7 4.7 1.3 0 61.5 2011 2012 0 0 0 5.5 0 0 0 5.5 2012 2013 0 1.1 1.4 4.7 35.8 8.8 0 51.8 2013 2014 0 0.2 5.4 24.8 23.9 3.2 0 57.5 2014 2015 0 0 0.3 22.8 15.2 23.9 0 62.2 2015 2016 0 0 Trace 18.8 14.3 2.7 0.1 35.9 2016 2017 0 0 4.1 14.3 15.8 7.9 0 42.1 2017 2018 0 0 7.4 21.2 1.3 21 4.3 55.2 2018 2019 0 4.6 Trace 1 3.5 6 0 15.1 2019 2020 0 2.19 3.8 2.7 0 0 0 8.69

A 40” season used to be a big deal before 2003. Now it’s just another above average season. This would make 10 years reaching 40” since 2003. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 2021-04-30 33.8 74 2020-04-30 4.8 1 2019-04-30 20.5 0 2018-04-30 40.9 0 2017-04-30 30.2 0 2016-04-30 32.8 0 2015-04-30 50.3 0 2014-04-30 57.4 0 2013-04-30 26.1 0 2012-04-30 7.4 0 2011-04-30 61.9 0 2010-04-30 51.4 0 2009-04-30 27.6 0 2008-04-30 11.9 0 2007-04-30 12.4 0 2006-04-30 40.0 0 2005-04-30 41.0 0 2004-04-30 42.6 0 2003-04-30 49.3 0

The 1980s Arctic outbreaks covered more real estate than this one. You can see how the US average temperatures on the peak outbreak days were colder in 1983 and 1989. Brian B has a fantastic post below comparing some of the strongest Arctic outbreaks back to 1899.

I agree with you. The US is much warmer now that it was during the 1980s and earlier times. The only area of small cold departures during the last 10 winter average has been focused over the Upper Plains. You can see how much more expansive the cold was across the US during the 1980s. So it makes sense that this historic cold outbreak was focused closer to the Plains. The 1989 Arctic outbreak matched the 1980s cold pattern which was more spread out over a wider area.

This was the 9th longest streak under 50° at Islip before the 50s today. Number of Consecutive Days Max Temperature < 50 for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Run Length Ending Date Period of record: 1963-09-05 to 2021-02-15 1 79 1968-03-10 2 62 2011-02-13 3 57 1977-02-15 4 54 2004-02-27 5 49 2015-03-08 6 48 1990-01-15 7 47 1985-02-18 8 45 1969-03-17 9 44 2021-02-15 - 44 1981-01-26

Looks like the Euro is overdoing the confluence in New England. So that 6”+ zone will probably bump north in later runs similar to the other guidance today.

Long Island will always eventually changeover with more tucked in storm tracks.

The forecast soundings look a little better this morning. Maybe we could sneak in a 3-6” front end thump at the coast before the sleet arrives. The high over New England is positioned better. We’ll see if we can hold this in coming days.

But the bigger snow piles are still doing OK.

Upper 40s and rain here in SW Suffolk with dense fog. Getting to see the first grassy patches of bare ground in a while. So it looks like the fog is quickly eroding the snowpack.

Very impressive run before the rapid rise this week.

Sure it is. Notice the SE Ridge or WAR extending more strongly into the Canadian Maritimes. Very difficult to lock in the surface CAD with a pattern like that. The 50/50 low got pushed further NE near Greenland. New run Old run

They need to improve the globals so they stop underestimating the SE Ridge. New Euro run Old run

The 12z Euro warmed up for tomorrow. Now has us getting into the 50s. So the early morning heavy thunderstorms could lead to some flooding issues with the big snow piles along the side of the roads.

RECORD EVENT REPORT NATIONAL WEATHER SERVICE SAN ANGELO TX 0749 AM CST MON FEB 15 2021 ...RECORD ALL-TIME MAXIMUM SNOWFALL SET AT ABILENE... AN ALL-TIME RECORD SNOWFALL OF 14.8 INCHES WAS SET AT ABILENE YESTERDAY FEBRUARY 14TH. THIS BREAKS THE OLD RECORD OF 9.3 INCHES SET ON APRIL 5 1996.

Long Island also averaged more snow than Newark from 95-96 to 08-09. I used BNL snowfall since there were several years of ISP missing data Newark averaged 25.5 inches over those years to 35.3 at BNL. There were no years over that stretch that EWR had 10” more than BNL in a single season. The only seasons that Newark had a 10” or more lead over Suffolk were 20-21 so far, 18-19, and 10-11. So big tucked in snowfall tracks like this year have been uncommon since 95-96. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Ending Date Islip Snowfall Newark Snowfall 2021-04-30 27.8 39.2 2020-04-30 6.8 6.9 2019-04-30 12.8 22.0 2018-04-30 65.9 39.4 2017-04-30 39.3 30.0 2016-04-30 41.4 32.8 2015-04-30 63.7 46.4 2014-04-30 63.7 61.1 2013-04-30 46.9 29.5 2012-04-30 4.7 8.8 2011-04-30 55.3 68.2 2010-04-30 53.8 47.9 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Ending Date Newark Snowfall Oct 1 to Apr 30 BNL LI Snowfall 2009-04-30 27.1 43 2008-04-30 14.6 11.5 2007-04-30 16.5 9.5 2006-04-30 37.9 30.5 2005-04-30 43.4 78.5 2004-04-30 47.8 60.2 2003-04-30 53.1 62.1 2002-04-30 3.6 5.5 2001-04-30 39.3 51.2 2000-04-30 18.4 14.0 1999-04-30 12.8 23.0 1998-04-30 6.9 4.5 1997-04-30 16.3 18.0 1996-04-30 78.4 90.7

While this winter is the snowiest in recent years, the storm track has still been tucked in near the coast. Newark has been ahead of snowfall at Islip for the last 2 out of 3 seasons with these closer to the coast storm tracks. Islip had the snowfall lead from 2013 to 2018 with more traditional benchmark tracks favoring eastern areas. It looks like the record SSTs off the coast have favored more ridging to the east during storm time. So the baroclinic zone has been further west. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Ending Date Islip Snowfall Newark Snowfall 2021-04-30 27.8 39.2 2020-04-30 6.8 6.9 2019-04-30 12.8 22.0 2018-04-30 65.9 39.4 2017-04-30 39.3 30.0 2016-04-30 41.4 32.8 2015-04-30 63.7 46.4 2014-04-30 63.7 61.1 2013-04-30 46.9 29.5 2012-04-30 4.7 8.8 2011-04-30 55.3 68.2 2010-04-30 53.8 47.9

Euro and NAM have a heavy elevated convection signal near the coast early Tuesday. So there could be quite a bit of ponding of water on the area roadways. Especially with the snowmelt and temperatures into the 40s. Should be an impressive temperature gradient between Toms River and Sussex County, NJ.

This is a great example of the October pattern repeating at some point during the winter. https://www.washingtonpost.com/weather/2020/10/27/oklahoma-ice-storm-power