bluewave

I believe the only lower reading was the -504 EPO around Christmas 1983.

Looks like the -428 EPO was one of the most negative readings for any time of the year. https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

Report of some graupel mixing in with the heavier snow squalls. Serious flurries & BIG graupel outside Marksboro, Warren Co., NJ. Never saw graupel almost the size of peas!

First snow squall warning of the day in Central PA as the bands take shape and head for our area this evening.

Around 38° may be the magic number for getting snow showers this evening across the area. Could be some localized heavy snow bursts with the mesos indicating surface based cape. WSW flow could add some ocean enhancement to the snow across parts of LI that are away from the warmer immediate beaches which could stay as rain at 40°. Simulated radar loops looking unusually convective for late November. So a few rumbles of thunder will be possible. http://www.meteo.psu.edu/fxg1/HRRRNE_CUR/rloop.html http://www.meteo.psu.edu/fxg1/NAMSFC4_12z/rloop.html

The storm track in about a week will probably come down to how amplified the system is. The OP Euro was more amplified so the low cuts to our west and goes negative tilt. The ensemble mean was more positive tilt with the trough so the low takes more of a coastal track. Sometimes the ensembles smooth things out too much longer range. So we still don’t know if this will be cutter, hugger, or coastal track. The other possibility is that we get a primary crossing the lakes and the secondary gets going too late and favors New England.

I think the OP run was holding the energy back too long in the SW so it squashed the southern stream. The EPS had a bunch of nice coastal hits among the 50 members as the low ejects faster than the OP. Looks similar to the GEPS. We just don’t want such a quick ejection that the the low ends up hugging the coast like the GFS or cuts like the OP GEM. But a genuine storm signal of some type is there.

Pretty good coastal signal on the day 8-9 EPS.

First snow showers/squalls of the season here Friday evening.

December will probably come down to how the WP warm pool influences the MJO. The cold pattern coming up and record -EPO is a rough match for MJO 6 in November. We need the MJO to continue into 7 to maintain that -EPO into December. The EPS now gets us to phase 7 in early December. The duration of the -NAO this time of year is tricky since it can depend on wave breaks to keep it going. Those are outside the range of the longer range guidance. So we want to keep the Pacific as favorable as possible since it’s has such a big influence on our weather.

It’s very extreme to get a 581 dm ridge in Alaska during November.

The strongest full Novembers for -EPO blocking at the 500 mb level were 2019, 2018, 2014, 2013, 1996, and 1978.

This is probably the biggest day 6-10 full EPS mean shift in one run in a long time. Much more Pacific blocking holds on after this record -EPO. So it’s not just one of these overamped OP runs with no ensemble support. 0z 12z

One of our greatest snowstorms of all time in January 2016 occurred after the +13.3 December. This was followed by the snowiest March on record for Long Island in 2018 following the 80° at Newark in February. The 16-17 winter had record 60s warmth the day before the February blizzard. Last winter ACY was in the 60s the day before their record January snowfall. So warm winters can be great for snow if the blocking decides to show up between the record warmth. But we can always strikeout in the snowfall department like in 18-19 and 19-20 if there is no blocking. But even both those years had record November and May snows.

Yeah, we have entered a semi permanent La Niña background state since the super El Niño in 15-16 with giant La Niña ridges south of Alaska and along the East Coast. So the last 7 winters have all been warmer to record warm across the area. Snowfall has been modulated by how much blocking we get.

The rapid expansion of the Western Pacific warm pool has been slowing the MJO in phases 5-7. Here we show that rapid warming over the tropical oceans during 1981–2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900–2018 and at an accelerated average rate of 4 × 105 km2(the size of California) per year during 1981–2018

I believe the 65” in 2014 was the greatest November event for east of Lake Erie. They have pure rocket fuel this time with the record 55° lake temperatures from the recent record warmth. The lake should be in the upper 40s by now. So it will just come down to how long the band stalls in any given location.

It was 12-17-83 at JFK and yesterday at ISP. 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 Frost/Freeze 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 Season Length 2022 03-30 (2022) 25 11-15 (2022) 29 229 1984 04-10 (1984) 30 11-15 (1984) 29 218 2016 04-10 (2016) 32 11-14 (2016) 32 217 1994 04-23 (1994) 32 11-12 (1994) 32 202 1981 04-22 (1981) 32 11-12 (1981) 31 203 1977 04-11 (1977) 32 11-12 (1977) 32 214

The latest freeze in NYC was 12-22-98 and at LGA 1-4-16. Frost/Freeze Summary for NY CITY CENTRAL PARK, 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 1998 03-23 (1998) 32 12-22 (1998) 22 273 2001 03-28 (2001) 30 12-16 (2001) 32 262 1948 04-04 (1948) 32 12-11 (1948) 31 250 2011 03-29 (2011) 31 12-10 (2011) 32 255 2016 04-10 (2016) 31 12-09 (2016) 29 242 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 2021 04-02 (2021) 29 12-19 (2021) 31 260 2011 03-29 (2011) 32 12-11 (2011) 31 256

Toronto just had their latest first freeze on record. But the first freeze this weekend in NYC will be around the average time since 2010. Islip tied their latest first freeze yesterday. Record -EPO will deliver the first widespread 20s of the season. Historic 500 mb heights near Alaska for this time of year. Frost/Freeze Summary for NY CITY CENTRAL PARK, 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 Minimum 03-01 (2020) 10-31 (2020) 215 Mean 03-28 11-19 235 Maximum 04-16 (2014) 12-10 (2011) 255 2021 04-03 (2021) 32 11-23 (2021) 32 233 2020 03-01 (2020) 25 10-31 (2020) 32 243 2019 03-18 (2019) 32 11-08 (2019) 29 234 2018 04-09 (2018) 32 11-14 (2018) 32 218 2017 03-23 (2017) 23 11-10 (2017) 25 231 2016 04-10 (2016) 31 12-09 (2016) 29 242 2015 04-01 (2015) 32 11-24 (2015) 32 236 2014 04-16 (2014) 31 11-18 (2014) 24 215 2013 03-23 (2013) 32 11-12 (2013) 31 233 2012 03-27 (2012) 30 11-06 (2012) 31 223 2011 03-29 (2011) 31 12-10 (2011) 32 255 2010 03-27 (2010) 29 12-04 (2010) 32 251

The average December snowfall in NYC declined from 9.4” to 3.1”. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 9.4 9.4 2002 11.0 11.0 2003 19.8 19.8 2004 3.0 3.0 2005 9.7 9.7 2006 0.0 0.0 2007 2.9 2.9 2008 6.0 6.0 2009 12.4 12.4 2010 20.1 20.1 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 3.1 3.1 2011 0.0 0.0 2012 0.4 0.4 2013 8.6 8.6 2014 1.0 1.0 2015 T T 2016 3.2 3.2 2017 7.7 7.7 2018 T T 2019 2.5 2.5 2020 10.5 10.5 2021 0.2 0.2

The big December climate shift occurred around 2011 following the epic run of cold and snowy Decembers from 2002 to 2010. The SSTs were much colder north of Australia back during those years. Also much more Atlantic blocking and colder SSTs east of our area. Since 2011, we had had the warmest run of Decembers on record. Plenty of MJO 5-6 forcing and a very +AO and +NAO pattern. Also notice the record warm pool east of New England. This record warm pool north of Australia had become a reoccurring theme. Notice the VP anomalies all focused in the 5-6 MJO region over the last decade.

Yeah, the location of the MJO forcing will probably determine the December pattern again. The loop back into phase 6 last December muted the influence of the normally colder phase 7. So the pattern stayed warm the whole month. It didn’t get cold until January when the MJO finally went into 8. The record warm pool near Indonesia in the Phase 6 area will probably give us a decent warm up late November into early December. The question then is does the MJO try to go into 7 or get stuck in the warmer Phase 6 again?

While the long range guidance has some Greenland Blocking, it tries to link up with the SE Ridge due to the +EPO and -PNA. This is what happened last December when the MJO looped back into 6 after going into 7. So the pattern will get very mild if there is another phase 6 stall. We would need a smooth progression from 7 into 8 for a colder pattern.

Islip ties the latest first freeze on record. Low of 29° on November 15th. The 2nd latest date was in 2016. Frost/Freeze 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. First Value 11-15 (1984) 29 11-15 (2022) 29 11-14( 2016) 32 11-12 (1981) 31 11-12 (1977) 32 11-12 (1994) 32