bluewave

Our last bookend La Niña was 17-18. Snowy mid-December to January 4th then early spring from mid-January through the 80° high in late February. Record snows in March to early April. 16-17 had a very even distribution of snow from December through March. It was really mild from late December through February. We had the famous Denver style 60° the day before the February blizzard. 10-11 was our last front-loaded La Niña winter with Newark recording 60"+ from late December to late January before the snows shut off. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Mar Apr Season 2016-2017 3.2 14.0 14.7 7.4 T 39.3 2017-2018 6.0 22.0 1.4 31.9 4.6 65.9 Maximum 35-Day Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Value Dates Missing Days Period of record: 1931-02-01 to 2021-11-06 1 61.6 2010-12-26 through 2011-01-29 0

The MJO going into phase 4-6 in mid to late November would support a big ridge over Western North America and colder temperatures in the East.

We’ll probably need one of the mid-November storm systems to amplify enough to get our first -10 departure of the fall. The last -10 departures occurred on the July 4th weekend. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=32&network=NYCLIMATE&station=NYC004&year=2016&var=avg&gddbase=50&gddceil=86&how=diff&cmap=jet&_r=t&dpi=100&_fmt=png

Yeah, 85-86 that was the last colder winter with below average snowfall. Several of the 1980s winters had patterns that haven’t repeated since. December 1980 was our last below zero Christmas. 1982 featured our last April blizzard with 3 daily consecutive record low temperatures. December 1989 was the last -10 departure December that averaged in the 20s.

Our last colder than average winter was 2014-2015. So we have had 6 warmer than normal winters in a row. Be interesting to see if our new warmer 1991-2020 climate normals make it easer to actually get a DJF below normal average temperature one of these winters. Luckily for the snow fans, we have had above normal snowfall for 4 out of those last 6 seasons.

The Euro seasonal DJF 500mb composite is a blend of the 16-17 and 17-18 La Ninas. The SE Ridge/WAR in the means kept those winters warmer than normal. But the poleward Aleutians ridge across the Arctic to Greenland gave us the -AO and -NAO intervals and above normal snows. Be interesting to see if the SEAS 5 comes close to the actual winter pattern.

The October NAO was the 2nd most negative on record for the month. But it was a continuation of the south based blocking like we saw last winter. Notice how much different this October was from the other 4 years below -2. The previous years were El Niño’s rather than the La Niña this year. So it will be interesting to see how things go as we head into December. https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table Top 5 lowest October NAO monthly averages -2.30….1968 -2.29…..2021 -2.28…..2002 -2.24…..2006 -2.06…..2012

Yeah, it still has the +PNA spike. But the SPV is a little stronger this run. So the Atlantic blocking later in November is extending north from east of New England. The last run with the weaker SPV had more Greenland blocking. But these SPV forecast beyond 10 days often change from run to run. So it may very well have another solution next week.

I think the models are going for a ridge over Western North America mid-November due to the MJO 5 La Niña standing wave. November is one of those months that convection near the Maritime Continent can force a ridge in that area. But it’s really uncertain how strong or long such a pattern would last. For later November into December, the blocking will probably determined by the strength of the SPV. And we know how uncertain these model SPV forecasts can be beyond the 6-10 day period. Our weather patterns from last November through the winter were very SPV driven. The very strong SPV in November lead to the record warmth. Then the SPV weakening was associated with the mid-December snowstorm. This was followed by record warmth on Christmas with the SPV rebound. Our best stretch of winter was in February following the major SSW.

What happens with the SPV next few weeks will probably determine how much blocking we get from later November into December.

Continuation of the colder departures further to the south theme. The departures yesterday were colder near DC than New England. We have seen this temperature departure pattern frequently this year. 11-3 departures CAR.…-2 BOS….-3 ISP…….-5 NYC…..-6 DCA……-8 Next several days more of the same Year to date temperature departures

That’s the kind of week 2 cold signal that could lead to a cold departure November if the late month blocking pattern comes to fruition.

That’s what it took to finally erase the persistent warm blob south of Alaska.

That’s one of the ways last winter was more like an El Niño. Snowy season following one of the warmest Novembers on record like 2009. We just had to wait until January for our record El Niño snows in 2015-2016. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Nov Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1975 52.7 0 2 2015 52.5 0 3 2009 51.0 0 - 2001 51.0 0 4 2020 50.9 0 - 1994 50.9 0 5 2011 50.8 0 - 2006 50.8 0 6 1948 50.7 0 7 2016 50.6 0 8 1982 50.4 0 9 1985 50.1 0

The latest first freeze at JFK was in 1983. Frost/Freeze Summary for JFK INTERNATIONAL AIRPORT, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Season Length 1983 03-30 (1983) 31 12-17 (1983) 31 261 1998 03-25 (1998) 31 12-14 (1998) 31 263 2016 04-10 (2016) 31 12-09 (2016) 31 242 2009 03-25 (2009) 31 12-07 (2009) 31 256 2006 04-05 (2006) 32 12-04 (2006) 31 242 1985 04-10 (1985) 29 12-02 (1985) 30 235 1975 04-07 (1975) 30 12-02 (1975) 32 238

Record lake effect snows with the warmest lake temperatures for so late in the season. RECORD EVENT REPORT NATIONAL WEATHER SERVICE 0234 AM EDT WED NOV 03 2021 ...RECORD DAILY NOVEMBER MAXIMUM SNOWFALL SET AT THE GAYLORD WEATHER FORECAST OFFICE... 11.7 INCHES BREAKS THE ALL TIME NOVEMBER DAILY SNOWFALL RECORD OF 10.7 INCHES SET BACK ON NOVEMBER 18TH, 2014. THIS IS ALSO THE 6TH HIGHEST ONE DAY TOTAL SNOWFALL FOR THE GAYLORD WEATHER FORECAST OFFICE SINCE RECORDS BEGAN BACK IN 1998.

2015-2016 was even more extreme at LGA. It was their only first freeze of the season to occur in January. Then it was followed by their biggest snowstorm on record. Frost/Freeze Summary for LAGUARDIA AIRPORT, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Season Length 2015 03-29 (2015) 27 01-04 (2016) 15 280 2001 03-28 (2001) 31 12-23 (2001) 32 269 1998 03-22 (1998) 31 12-22 (1998) 24 274 2011 03-29 (2011) 32 12-11 (2011) 31 256 1948 04-10 (1948) 32 12-11 (1948) 32 244 Maximum 3-Day Total Snowfall for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days Period of record: 1940-01-01 to 2021-11-02 1 28.2 2016-01-25 0 - 28.2 2016-01-24 0 27.9 2016-01-23 0 2 25.4 2006-02-13 0 - 25.4 2006-02-12 0 3 24.2 1996-01-09 0 23.8 1996-01-08 0 23.3 2006-02-14 0 4 22.8 1947-12-28 0 - 22.8 1947-12-27 0

Gorgeous photos of the sea smoke on the Long Island Sound with the SSTs still in the low 60s.

Places that miss their first freeze this week will get another chance mid-November as the trough returns to the East.

Low of 37° here in SW Suffolk with the first frost of the season on the cars and rooftops.

POU finally ends its longest above freezing streak at 210 days. Number of Consecutive Days Min Temperature > 32 for Poughkeepsie Area, NY (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Run Length Dates Last value also occurred in one or more previous years. Period of record: 1931-01-01 to 2021-11-02 1 210 2021-04-07 through 2021-11-02 2 197 1942-04-15 through 1942-10-28 3 194 1971-04-25 through 1971-11-04 4 190 2007-04-22 through 2007-10-28 - 190 1975-04-23 through 1975-10-29 5 183 1990-04-20 through 1990-10-19 6 178 2016-04-16 through 2016-10-10 - 178 1946-04-19 through 1946-10-13 - 178 1944-04-20 through 1944-10-14 7 177 2018-04-24 through 2018-10-17

This is the 2nd latest first 30s at Islip. First/Last Summary for ISLIP-LI MACARTHUR AP, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Difference 1971 05-05 (1971) 39 11-04 (1971) 39 182 2017 05-04 (2017) 39 11-01 (2017) 36 180 2011 05-06 (2011) 38 10-28 (2011) 37 174 1967 05-09 (1967) 38 10-26 (1967) 38 169

The EPS has a back and forth pattern also. Cool down this week followed by warm up next week. Another potential cool down showing up for the third week of November. 12z Nov 17th

The number of snow cover days held steady as temperatures and snowfall increased.

The last cold winter with memorable snowstorms was 10-11. While 13-14 and 14-15 were snowy, no one snowstorm really stood out. The lasting storm memory in 14-15 was the January snowstorm shifting east at the last minute. While 15-16 was one of our warmest winters on record, it also produced the heaviest snowstorm around NYC near 30”. The next year was almost as warm with 60s the day before the February blizzard. Although the 950 mb benchmark blizzard in January 2018 came at the end of a cold streak, the warmth in February was more impressive with our first 80°. March was the snowiest on record for Long Island. So while the last 6 winters have featured above normal to record temperatures, there has been no shortage of memorable snowstorms.