bluewave

It’s been an active last few years. NYC is on track to reach 50 inches of precipitation for the 2nd year in a row. Monthly Total Precipitation for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2018 2.18 5.83 5.17 5.78 3.53 3.11 7.45 8.59 6.19 3.59 7.62 6.51 65.55 2019 3.58 3.14 3.87 4.55 6.82 5.46 5.77 3.70 0.95 6.15 1.95 2.69 48.63

The dominant story since 2018 continues to be the raging Pacific Jet. Next soaking rainfall possible on the weekend.

I.63 in Wantagh so far.

It’s been a while.The last 1.00”+ liquid equivalent snow event in NYC during December was in 2010. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Precipitation Snowfall 2010-12-26 1.09 12.2 2010-12-27 0.52 7.8

Currently looks like the best chance for NYC accumulation should be the colder surfaces like the grass in Central Park.

Another top 10 year for days with measurable precipitation in NYC. On track for a top 5 finish following the 1st place finish last year. Time Series Summary for NY CITY CENTRAL PARK, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Precipitation >= .01 Missing Count 1 2018 158 0 2 1996 152 0 3 1972 145 0 4 2003 142 0 5 2008 141 0 - 1950 141 0 6 1938 140 0 - 1920 140 0 - 1898 140 0 7 1919 139 0 8 1956 138 0 - 2019 138 22

Short duration snow cover has been the norm this decade. The exceptions were 2011, 2014, and 2015. But I don’t mind quick warm ups after snow as long as it’s a quality storm. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Number of Days Snow Depth >= 1 Oct 1 to Apr 30 Seasonal Snowfall 2019-04-30 12 20.5 2018-04-30 20 40.9 2017-04-30 20 30.2 2016-04-30 11 32.8 2015-04-30 55 50.3 2014-04-30 59 57.4 2013-04-30 11 26.1 2012-04-30 3 7.4 2011-04-30 57 61.9 2010-04-30 25 51.4

I wouldn’t go by the GEFS since it’s been running too cold.

Just go back a few pages. We have been discussing the -EPO relaxation. Along with the seasonal pattern of December beginning with colder departures and gradually moderating as the month goes on.

A 41 degree temperature rise out at FOK in 24 hrs. It went from 10 degrees to 51 now with the strong WAA. https://www.wrh.noaa.gov/mesowest/getobext.php?sid=KFOK&table=1&num=168&banner=off

It would be nice to get back to the benchmark KU snowstorm pattern that ran up through March 2018. While small or moderate snows are OK, they can’t compare with high end events.This recent pattern has been more like something from the 80’s into the early 90’s. You learn to appreciate whatever snows you can get.

We generally need a high impact event like a rapidly deepening low to pull it off. It also helps to be closer to a climatologically colder and snowier part of the winter. Under these circumstances we can go from 60 degrees to a 12”+. https://www.weather.gov/okx/Blizzard_Feb92017

Piece of cake with a low bombing out near the benchmark in the heart of winter like 2-9-17.

I guess it comes down to the biggest snows in NYC usually sharing the wealth with the wider area. One exception was February 2006 which wasn’t as good in some spots. But the best snows in NYC generally mean many surrounding areas do very well. January 2016 was a great example of this.

The Euro has 3.8” as frozen including mixed for NYC. It starts at 38 and ends at 32. So cut that in half for cold surface accusation to around 2”. The coating is if later runs decrease the precipitation and it’s a little warmer. The 3 could be some colder spots like the North Shore of Long Island with a heavier snow burst and the temp falling to 31.

You know that people are hungry for snow after last winter. If a coating to 3 mainly on colder surfaces potential causes all this bickering, then better hope the KU snow machine cranks up before the winter is over. I can’t even imagine what this place would have been like from 96-97 to 01-02. Or even 79-80 to 91-92 for that matter.

The timing for any potential weakening of the -EPO may begin just before the solstice. We have seen this temperature moderation period often during the last decade. Even the MJO remaining in the weaker circle portion of phases 4-5 could produce a temperature moderation. Not really speculating on what things look like all the way out to January yet.

Longer range, it looks like convection migrating toward the Maritime Continent may weaken the -EPO. We’ll see how it goes. EPO forecast courtesy of Bamwx on twitter from weathermodels.com

Easily the snowiest first week of December on record for Albany. Time Series Summary for Albany Area, NY (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Dec 1 to Dec 7 Missing Count 1 2019-12-07 24.5 1 2 2003-12-07 19.2 0 3 1977-12-07 12.4 0 4 1902-12-07 10.3 0 5 1926-12-07 10.2 0 6 1901-12-07 10.0 0

Portions of the area could see a 40 degree drop in temperatures from late Tuesday into early Thursday. A 42 degree drop in 36 hours for Newark is the December record set in 1990. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&hours=36&month=dec&dir=cool&dpi=100&_fmt=png

The EPS has been too warm while the GEFS has been too cold. But these biases can change in the future. https://www.frontierweather.com/verification.html

I will look on the positive side. That November snow prevented parts of the area from finishing the season in the single digits. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 12.8

The rapid warming of the NW Atlantic independent of the AMO may be an even bigger story for all the extreme coastal storms we continue to see. https://phys.org/news/2016-01-northwest-atlantic-ocean-warmer-sooner.html

Yeah, small 1-2 inch events like the other day are nice. But we need the help of multiple warning level snow events for a normal to above normal snowfall season.

December 2013 was a +NAO and -EPO pattern also. My guess is that the warming WPAC is giving us this low frequency forcing pattern. We got a lucky SFWE on 12-13-14. So NYC finished with above normal snowfall in December. But the MJO going into 4-5 spoiled the party with the 70 degree temperatures around the solstice. That was the only reason NYC finished +1 instead of a cold departure. So root for the MJO to stay weak the rest of the month with a lucky SWFE.