bluewave

These past 2 events were unusual for their intensity across the whole region. Snow squalls usually just affect parts of the area. It’s pretty rare to get two events in the same calendar year that don’t weaken as they cross the area. The one last winter produced the heaviest snowfall rates of the season. This time it was the heaviest rates through at least December. I can’t really remember the last time a snow squall produced the seasons peak snowfall rate. Maybe Uncle can remember if the January 1977 squall was the heaviest rate for that season. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall 1977-01-28 44 13 0.02 0.2 1977-01-29 13 1 0.00 0.0 1977-01-30 19 10 0.00 0.0 1977-01-31 22 8 0.00 0.0

These snow squalls are very location specific like summer thunderstorms. Last January for me was more extreme with stronger winds and lower visibility. So I guess you were in a better spot for this one than me. But it’s interesting how we got two such potent events this close together in time. Must be a product of the fast Pacific flow and rapid 500 mb wavelength changes. Notice how last year also had short the Arctic outbreak and temperature moderation a few days later. But the lows and highs over the next week will be less extreme. Another version of 2010’s repeating weather patterns. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Snowfall 2019-01-30 35 6 0.4 2019-01-31 16 2 0.0 2019-02-01 21 11 0.0 2019-02-02 34 16 0.0 2019-02-03 53 33 0.0 2019-02-04 61 41 0.0 2019-02-05 65 44 0.0

Yeah, 4 out of the last 5 years with March being the snowiest month was more like the Rockies and Plains. Welcome to the 2010’s. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season 2014-2015 0.0 0.2 1.0 16.9 13.6 18.6 0.0 50.3 2015-2016 0.0 0.0 T 27.9 4.0 0.9 T 32.8 2016-2017 0.0 T 3.2 7.9 9.4 9.7 0.0 30.2 2017-2018 0.0 T 7.7 11.2 4.9 11.6 5.5 40.9 2018-2019 0.0 6.4 T 1.1 2.6 10.4 0.0 20.5

NYC also has a shot at March surpassing December for average snowfall. 1991-2019 NYC average monthly snowfall. December.....4.9 March............5.1

Yeah, the 2nd lowest by year. Only 2017 dropped below 16 degrees.

You know it’s the 2010’s when Chicago gets record snowfall on Halloween and none on Christmas.

In a decade defined by December warmth, the 16 in NYC is the 2nd coldest December minimum of the 2010’s. The last week of 2017 holds the record for lowest December temperatures of the decade. NYC had 6 consecutive December days below freezing with a low of 9. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Year Lowest Min Temperature Missing Count 2019 16 13 2018 24 0 2017 9 0 2016 17 0 2015 34 0 2014 24 0 2013 19 0 2012 28 0 2011 22 0 2010 19 0 Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature 2017-12-26 28 23 2017-12-27 24 17 2017-12-28 18 11 2017-12-29 22 11 2017-12-30 23 17 2017-12-31 21 9

It got heavy here in SW Suffolk for a few minutes. Just enough to coat the ground. But it didn’t reach the intensity of the snow squall last January.

The good stuff is getting close to you.

Whiteout now at the NYC mesonet.

View from NYC mesonet.

The heaviest snowfall rates all last winter was with a snow squall also.

.2 of a mile for a few minutes so far at TEB. http://wxweb.meteostar.com/meteogram/link.shtml?choice=KTEB

Visibility dropped to .2 of a mile at FWN when the squall came through. http://wxweb.meteostar.com/meteogram/link.shtml?choice=KFWN

The models do show the squall over NEPA holding together down to the coast later.

At least get your facts straight if you are going to be posting comments like that. The Euro isn’t 15 degrees colder than the GFS MOS on Christmas Eve. The 23rd and 24th high temperatures are similar to the GFS MOS. We’ll just have to wait and see how close the forecasts come to the actual high temperatures on those days. NEW YORK CITY-CENTRAL PARK KNYC GFSX MOS GUIDANCE 12/18/2019 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 WED 18| THU 19| FRI 20| SAT 21| SUN 22| MON 23| TUE 24| WED 25 CLIMO X/N 37| 17 25| 21 34| 26 36| 31 45| 36 51| 44 53| 38 46 28 41 TMP 29| 18 24| 23 32| 27 35| 33 43| 38 48| 45 48| 39 43

This was only the 10th year that JFK finished with over 50 inches of precipitation. 5 of the top 10 wettest years occurred since 2004. Time Series Summary for JFK INTL AP, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 1983 59.12 0 2 2018 57.40 0 3 1975 57.18 0 4 2011 55.78 0 5 1989 55.73 0 6 1984 53.22 0 7 1996 51.45 0 8 2019 51.13 14 9 2004 50.95 0 10 2014 50.75 0

Pretty impressive for JFK to record its wettest December on record by the 17th of the month. The top 3 spots have occurred in just the last 6 years. Just goes to show how wet our climate has become. Time Series Summary for JFK INTL AP, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2019 7.17 14 2 2014 7.04 0 3 2018 6.76 0 4 1986 6.73 0 5 2009 6.25 0 6 1969 6.16 0 7 1983 6.14 0 8 1974 6.07 0 9 1948 6.05 0 10 1996 6.00 0

Quick Arctic shot coming up next few days. Then we get our annual warm up potential before Christmas. The monthly departures will be decided by the temperatures during the last week of the month. The average NYC high and low for the last week of December is 40/29. So anything above 40 degrees is considered mild. NEW YORK CITY-CENTRAL PARK KNYC GFSX MOS GUIDANCE 12/18/2019 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 WED 18| THU 19| FRI 20| SAT 21| SUN 22| MON 23| TUE 24| WED 25 CLIMO X/N 37| 17 25| 21 34| 26 36| 31 45| 36 51| 44 53| 38 46 28 41 TMP 29| 18 24| 23 32| 27 35| 33 43| 38 48| 45 48| 39 43

Warm and wet storm track followed by cold and dry. But the last true Arctic air mass was over a month ago. Plenty of Pacific modification to the air mass over the CONUS.

The EPS is a carbon copy of the GEFS.

Yeah, one the heaviest 2 day rainfalls on record for December. Maximum 2-Day Total Precipitation for JFK INTL AP, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days Period of record: 1948-07-17 to 2019-12-16 1 3.23 2008-12-12 0 2 3.15 2014-12-10 0 3 3.04 2014-12-09 0 4 3.00 1992-12-11 0 5 2.95 1996-12-07 0 6 2.86 1948-12-31 0 7 2.77 2019-12-14 0 8 2.75 1992-12-12 0 9 2.46 1974-12-17 0 - 2.46 1974-12-16 0

This was the wettest first 16 days of December on record at JFK. Time Series Summary for JFK INTL AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Dec 1 to Dec 16 Missing Count 1 2019-12-16 6.10 0 2 2014-12-16 5.60 0 3 1974-12-16 5.48 0 4 1996-12-16 5.07 0 5 2008-12-16 3.99 0

The first 17 days of the month have been near the wettest on record. So we need a break. The holiday shoppers and travelers will appreciate the step down in heavy precipitation.

The next week to 10 days looks drier than 12/1 to 12/17 as the ridge builds over the East.