bluewave

Very consistent Great Lakes cutter, coastal hugger, and southern stream suppressed storm track since last winter.

A remarkable shift to extreme winter warmth since December 2015. This will be the 11th warmer than average winter month in NYC out of the last 14. Monthly warmest records were set in December 2015 and February 2018. February 2017 was 2nd warmest and January 2017 was 11th warmest. January 2020 is currently 8th warmest on record. NYC Dec 15...+13.3...#1 Jan 16....+1.9 Feb 16....+2.4 Dec 16...+0.8 Jan 17...+5.4...#12 Feb 17...+6.3...#2 Dec 17...-2.5 Jan 18...-0.9 Feb 18...+6.7..#1 Dec..18..+2.6 Jan...19..-0.1 Feb...19..+0.9 Dec...19..+0.8 Jan...20...+6.8.....#8 so far

While this doesn’t diminish in any way the recent era snowfall extremes, many of those older storms were undermeasured by modern standards. https://news.ucar.edu/14009/snowfall-measurement-flaky-history Earlier in our weather history, the standard practice was to record snowfall amounts less frequently, such as every 12 or 24 hours, or even to take just one measurement of depth on the ground at the end of the storm. You might think that one or two measurements per day should add up to pretty much the same as measurements taken every 6 hours during the storm. It’s a logical assumption, but you would be mistaken. Snow on the ground gets compacted as additional snow falls. Therefore, multiple measurements during a storm typically result in a higher total than if snowfall is derived from just one or two measurements per day. That can make quite a significant difference. It turns out that it’s not uncommon for the snow on the ground at the end of a storm to be 15 to 20 percent less than the total that would be derived from multiple snowboard measurements. As the cooperative climate observer for Boulder, Colorado, I examined the 15 biggest snowfalls of the last two decades, all measured at the NOAA campus in Boulder. The sum of the snowboard measurements averaged 17 percent greater than the maximum depth on the ground at the end of the storm. For a 20-inch snowfall, that would be a boost of 3.4 inches—enough to dethrone many close rivals on the top-10 snowstorm list that were not necessarily lesser storms!

Snowfall has been a challenge last 2 winters with such a strong ridge stuck north of Hawaii.

Most stations around the region will finish with the top 5 warmest January minimum temperatures on record. Time Series Summary for New York-Central Park Area, NY (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1937 25 0 2 1990 24 0 - 1932 24 0 3 2002 21 0 - 1993 21 0 - 1953 21 0 4 2020 20 3 - 1949 20 0 Time Series Summary for Islip Area, NY (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1990 21 0 2 1993 18 0 3 2020 16 3 4 2002 15 0 - 1998 15 0 Time Series Summary for Albany Area, NY (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1932 16 0 2 1990 12 0 3 1937 11 0 4 1953 10 0 - 1913 10 0 5 2020 7 3 Time Series Summary for Binghamton Area, NY (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2002 11 0 2 1990 10 0 - 1960 10 0 3 1953 9 0 4 2001 7 0 5 1993 6 0 6 2020 5 3 - 1980 5 0 Time Series Summary for Boston Area, MA (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2002 22 0 2 1932 18 0 3 1953 15 0 - 1937 15 0 4 2020 14 3 - 1990 14 0 - 1949 14 0 Time Series Summary for Philadelphia Area, PA (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1937 25 0 2 1953 23 0 - 1932 23 0 3 1993 22 0 - 1913 22 0 4 2006 20 0 - 2002 20 0 - 1990 20 0 - 1950 20 0 5 2020 19 3 Time Series Summary for Atlantic City Area, NJ (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1949 22 0 2 1953 21 0 3 2020 17 3 - 1960 17 0 - 1950 17 0 Time Series Summary for STATE COLLEGE, PA - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2006 18 0 2 1990 17 0 3 1953 16 0 - 1932 16 0 4 1950 15 0 - 1937 15 1 5 2020 13 3 Time Series Summary for Washington Area, DC (ThreadEx) - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1937 29 0 2 1990 26 0 3 2006 25 0 - 1953 25 0 - 1932 25 0 4 1913 24 0 5 2020 23 3

Look how close the 500 mb pattern was to MJO 4-5 and La Niña.

Very big surprise for the Alaskan forecasters to get such a strong Niña-like pattern without actually having one. Must be the combination of the record MJO, record WPAC warm pool, and PV alignment. http://ak-wx.blogspot.com

One of the strongest January +EPO patterns on record will do it for them. Like a La Niña without actually having one.

Record storms around the Mediterranean. https://www.surfertoday.com/environment/storm-gloria-generates-the-biggest-wave-ever-recorded-in-the-mediterranean https://www.timesofisrael.com/torrential-rains-in-northern-israel-break-51-year-record/

The warmth in Europe has been even more impressive than here.

Yeah, the flip around the solstice was very dramatic. We were -2 to -3 before then. But quickly reversed to the 5th warmest on record since December 22nd. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Dec 22 to Jan 27 Missing Count 1 1932-01-27 42.7 0 2 1950-01-27 41.9 0 - 1933-01-27 41.9 0 3 1937-01-27 40.8 0 4 2006-01-27 40.5 0 5 2020-01-27 40.4 0 6 2007-01-27 40.1 0 7 1913-01-27 39.9 0 8 2017-01-27 39.3 0 - 1995-01-27 39.3 0 9 1998-01-27 39.1 0 10 2016-01-27 38.8 0

A top 10 warmest January for many. The winter temperature departures since December 1st are +3 to +8 across the East. Big reduction in home heating costs for a large amount of customers.

The exact evolution may have to wait to within the NAM’s best range. Plenty going on with the fast northern stream and timing of the southern stream shortwave ejection. A perfectly timed phase and UL track will be necessary to compensate for the lack of high pressure to the N and NW. It’s been a while since a phase worked out for us.

Just one record after another for winter warmth since December 2015. Those 13-14 and 14-15 seasons seem like a long time ago.

Yeah, timing of the phase and surface and UL track will be critical.

We would probably also need the UL to close off right over the area to make up for the lack of any high pressure to the N or NW.

The January highs and lows were nearly identical to Atlanta so far. Atlanta.....72....23 NYC..........69....20.......EWR.....70....20

Long range model skill may be ready to make another decline. They have dueling areas of forcing in the IO and WPAC. So it’s no surprise that their MJO forecasts are all different. Plus check out this big Jet extension across most of the Northern Hemisphere.

The heavy rain on Saturday was part of another repeating weather pattern since 2010. The heaviest January precipitation event occurred right around the same date late in January. This makes 8 out of the last 11 years for the area. Heaviest January precipitation events since 2010 1-25-20.....Wantagh....1.28 1-24-19......NYC...1.33....EWR.....1-19/20-19...1.52 1-23/24-17......NYC...2.34...T 1-23-16......NYC...2.31....27.3 1-27-15......ISP....1.44......17.4 1-31-13......NYC...0.90 1-26/27-11....NYC....2.06...19.0 1-25-10.....NYC...1.25

28 out of the last 34 days had above normal temperatures. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Avg Temperature Departure 2019-12-23 13.8 2019-12-24 6.5 2019-12-25 4.7 2019-12-26 6.5 2019-12-27 15.7 2019-12-28 12.9 2019-12-29 7.6 2019-12-30 5.3 2019-12-31 6.9 2020-01-01 4.1 2020-01-02 7.7 2020-01-03 13.4 2020-01-04 13.0 2020-01-05 5.6 2020-01-06 5.7 2020-01-07 7.8 2020-01-08 2.4 2020-01-09 -4.0 2020-01-10 11.6 2020-01-11 27.6 2020-01-12 23.2 2020-01-13 9.2 2020-01-14 10.2 2020-01-15 13.2 2020-01-16 8.8 2020-01-17 -5.2 2020-01-18 -3.8 2020-01-19 2.7 2020-01-20 -6.8 2020-01-21 -5.8 2020-01-22 -0.9 2020-01-23 7.6 2020-01-24 11.5 2020-01-25 12.0

Looks like Newark did it in January 1932.

Newark made it to 70 and 69 on those two days. JFK reached 68 degrees.

Heaviest downpour in a while to move through through SW Suffolk. Wantagh mesonet to my west is at 1.11 of rain. Probably some street flooding in the usual spots.

Yeah, it usually comes down to getting a deep enough system near the benchmark with a high to the N or NW or favorable UL track. Even brief -NAO or -AO intervals can produce that track for us. My favorite example of this was February 2017. That was one of our warmest Februaries on record averaging around 40 degrees. It’s close to the same temperature we have averaged since late December. But all it took that month was a brief -AO /-NAO drop to produce. March 2018 really delivered for us while averaging around 40 degrees. But the extended strong blocking and proper high pressure placement locked in the the benchmark storm track for multiple events. That’s why I am more about the right storm track and teleconnections rather than absolute temperature departures for snowfall. Last winter was all about the wrong storm track and intervals of cold going to waste. This winter so far was a combination of poor storm track and warmth. So you hope that we can capitalize on any blocking intervals we get during the remainder of the season. But there are no guarantees.

We weren’t even the warmest relative to the means across the Northern Hemisphere. The ridge stuck north of Hawaii with the +EPO and +NAO Is a very mild winter pattern for us. We would probably be talking about 100 degree days if this was the summer.