bluewave

Preliminary AO data suggests that we may have a new 2nd highest reading following the record on February 10th. The first month with two +6 or higher values. https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/daily.index.ascii 01Feb2020 0.20221E+01 -0.52677E-01 0.29204E+00 -0.64548E+00 02Feb2020 0.18573E+01 0.21773E+00 0.20699E+00 -0.55492E+00 03Feb2020 0.12789E+01 0.15999E-01 0.71990E-01 0.41582E+00 04Feb2020 0.11909E+01 -0.10099E+00 0.56737E-01 0.79638E+00 05Feb2020 0.11668E+01 -0.29145E+00 0.34918E+00 0.96277E+00 06Feb2020 0.21146E+01 -0.21840E+00 0.56460E+00 0.11092E+01 07Feb2020 0.22717E+01 0.24262E+00 0.94827E+00 0.37856E+00 08Feb2020 0.31727E+01 0.82119E+00 0.87266E+00 -0.29577E+00 09Feb2020 0.51799E+01 0.14128E+01 0.44704E+00 -0.61452E+00 10Feb2020 0.63415E+01 0.15626E+01 -0.16199E+00 -0.78893E+00 11Feb2020 0.52334E+01 0.12471E+01 -0.42390E+00 -0.63371E+00 12Feb2020 0.32855E+01 0.10390E+01 -0.15466E+00 0.42111E+00 13Feb2020 0.18597E+01 0.79792E+00 0.64890E-01 0.11103E+01 14Feb2020 0.16864E+01 0.83402E+00 0.19030E+00 0.59934E+00 15Feb2020 0.27003E+01 0.11294E+01 0.25389E+00 -0.32445E+00 16Feb2020 0.41686E+01 0.12515E+01 0.12688E+00 -0.45273E+00 17Feb2020 0.47429E+01 0.12109E+01 0.62894E-01 0.58521E-01 18Feb2020 0.46598E+01 0.10510E+01 0.97554E-01 0.70548E-01 19Feb2020 0.43469E+01 0.10294E+01 0.21451E-01 -0.29174E+00 20Feb2020 0.43393E+01 0.10597E+01 0.13981E+00 -0.19496E+00 21Feb2020 0.58365E+01 0.12835E+01 0.22726E+00 0.24356E+00 22Feb2020 0.61873E+01 0.15184E+01 0.26919E+00 0.85533E+00 Date AO NAO PNA AAO

The GEFS cold bias strikes again. https://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

First time that several of our stations don’t even have a trace of snow for February.

Could be another year with close in powerful hurricane activity.

Yeah, this has easily been our warmest 5 winter period on record. Average winter temperatures near 40 degrees are typical for Richmond, Virginia. https://www.weather.gov/media/akq/climateRECORDS/RIC_AVE_T.pdf Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Season Mean Avg Temperature Departure 2019-2020 39.0 +3.9 2018-2019 36.3 +1.2 2017-2018 36.1 +1.0 2016-2017 39.3 +4.2 2015-2016 41.0 +5.9

Today will be one of our rare cold departure days before we warm back up to around 50 degrees over the weekend. NYC is currently in 8th place for warmest winter. The 39.0 degree average is close to +4 for the winter. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2001-2002 41.6 0 2 2015-2016 41.0 0 3 2011-2012 40.5 0 4 1931-1932 40.2 0 5 1997-1998 39.6 0 6 2016-2017 39.3 0 7 1990-1991 39.1 0 8 2019-2020 39.0 9 9 1998-1999 38.6 0 10 1948-1949 38.5 0

I agree. Certain signals must just be easier for models to detect in the fall. We often see different models exhibit better skill with one element of the forecast than another. This winter some models did better with the AO and NAO than last year. But while they indicated another year with the ridge north of Hawaii, the strength of the +EPO wasn’t we’ll forecast in advance. Last winter may have come down to the models missing the the fact that the El Niño never was able to couple. Several of us were discussing in the fall of 2018 how the SST configuration wasn’t aligned with the typical El Niño pattern. The SOI fall reversal was also a red flag that seasonal forecasts would struggle. So it’s always a challenge to know exactly what if any forecast elements the seasonal models will have success with. ENSO blog write up on last winter https://www.climate.gov/news-features/blogs/enso/csi-enso-case-missing-central-pacific-rainfall

We will find out next fall and winter whether this was another two year stuck pattern like 2009-2011, 2013-2015 and 2016-2018. Two year stuck winter patterns have been the maximum since 2010. Hopefully, this isn’t a throwback to the longer snow droughts of the late 1990’s and early 2000’s.

Most of the seasonal models had a strong +NAO +AO for the winter from the fall forecasts. Some research points to the record +IOD late in the fall into early winter. While several seasonal models had the strong ridge north of Hawaii, they all underestimated the strength of the +EPO.

This Niña-like background state with a struggling El Niño hasn’t worked for snowfall the last two winters. The ridge just stays stuck north of Hawaii leading to the cutter, hugger, and suppressed southern stream storm tracks. We may need a stronger El Niño or official La Niña in coming winters to boost our snowfall potential again.

That just goes to show how important the storm track and teleconnections are for snow here. Both winters featured that strong ridge stuck just north of Hawaii. So we had similar DJF snowfall even though this winter was 3 degrees warmer.

97-98 finished the whole snowfall season 7th lowest. They had the benefit of a -AO for DJFM that finally clicked for them on 3-22 with 5.0”. But this year we continue with the record SPV and +AO. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1973-04-30 2.8 0 2 2002-04-30 3.5 0 3 1919-04-30 3.8 0 4 2020-04-30 4.8 72 5 1901-04-30 5.1 2 6 1932-04-30 5.3 0 7 1998-04-30 5.5 0 8 2012-04-30 7.4 0 9 1989-04-30 8.1 0 - 1878-04-30 8.1 0 10 1951-04-30 9.3 0

This is the same winter snowfall pattern as last year. It’s 9th lowest in snowfall and last winter finished 7th. Identical storm track pattern of cutter, hugger, and southern stream suppressed snowstorms. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Total Snowfall Missing Count 1 1997-1998 0.5 0 2 1918-1919 1.1 0 3 1972-1973 2.6 0 4 1931-1932 2.7 0 5 1991-1992 3.2 0 6 2001-2002 3.5 0 7 2018-2019 3.7 0 8 2011-2012 4.5 0 9 2019-2020 4.8 10 10 1989-1990 5.0 0

Last July was really close. 7-21-19 set or tied multiple record high temperatures at 99 degrees. Since the dew points were so high, the heat indices were similar to 7-22-11. The month also finished top 10 warmest around +3. JFK came within 1 degree of the all-time highest heat index at 114 degrees.

The record +AO just reinforces that background North Atlantic SST pattern that has been stuck in place for years. So we get record SST warmth off the East Coast and that cold pool south of Greemland.

You can see how quickly the models pull the ridge back to the Aleutians. This strong +EPO/-PDO is different from recent years. So this March may turn out warmer than we have experienced from 2017 to 2019.

Yeah, it will be interesting to see if we can pick up any snow this March. The lack of measurable snowfall since January 20th is different from recent years. This is the first time since 2002 with no measurable snowfall during the peak of the season. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Jan 20 to Feb 20 Missing Count 2020-02-20 T 3 2019-02-20 2.9 0 2018-02-20 5.9 0 2017-02-20 10.4 0 2016-02-20 31.5 0 2015-02-20 24.0 0 2014-02-20 42.1 0 2013-02-20 13.7 0 2012-02-20 4.5 0 2011-02-20 25.8 0 2010-02-20 17.3 0 2009-02-20 7.3 0 2008-02-20 2.8 0 2007-02-20 4.3 0 2006-02-20 26.9 0 2005-02-20 15.5 0 2004-02-20 11.0 0 2003-02-20 28.6 0 2002-02-20 T 0

The bar is set pretty low this year. All NYC needs is 2.6 inches of snow in March to make it the snowiest month of the season. It would be the 5th time since 14-15 if NYC can pull it off. 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 2019-2020 0.0 0.0 2.5 2.3 T M M 4.8

Just a remarkable shift to winter warmth since December 2015. Your area is also in 4th place. 3 top 4 finishes in 5 winters is as extreme as it gets. Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Number of Days Min Temperature > 32 Missing Count 1 2015-2016 44 0 2 2016-2017 40 0 3 2011-2012 38 0 - 2001-2002 38 0 4 2019-2020 36 11

NYC moves into 4th place for most winter days with the low temperature remaining above freezing. Today was the 49th day. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Number of Days Min Temperature > 32 Missing Count 1 2011-2012 58 0 - 1997-1998 58 0 2 2016-2017 55 0 - 2015-2016 55 0 - 2001-2002 55 0 3 1931-1932 53 0 4 1998-1999 49 0 2019-2020 49 11

Today is 19th day to reach 50 or warmer at Newark since December 22nd. It’s the 4th highest number of days for the time period. Feels like an early spring day out there. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Number of Days Max Temperature >= 50 Dec 22 to Feb 17 Missing Count 1 2006-02-17 22 0 2 2012-02-17 21 0 - 1990-02-17 21 0 - 1932-02-17 21 0 3 1991-02-17 20 0 - 1950-02-17 20 0 4 1972-02-17 19 0 - 1933-02-17 19 0 2020-02-17 19 0

It’s been a real challenge with this Niña background pattern. This is the first time since the early 2010’s that the +EPO was strong enough to drop the -PDO this much.

We will have to make due with a much weaker -EPO than we had near the end of Feb and start of Mar last year. The AO is also much more positive this year coming off the current record breaking period. Looks like a transient +PNA before the ridge pulls back near the Aleutians.

Models have been too aggressive with the -EPO long range all winter. So this is no big surprise. It looks like we may get a transient +PNA near the start of March before the ridge pulls back closer to the Aleutians. We had a decent -EPO at this time last year which extended into March.

This is only our 6th time with no measurable snowfall during the peak snowfall season so far. It’s also the first time that this has occurred since 2002 and 1998. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Jan 20 to Feb 16 Missing Count 1 1890-02-16 0.0 0 2 2020-02-16 T 0 - 2002-02-16 T 0 - 1998-02-16 T 0 - 1981-02-16 T 0 - 1968-02-16 T 0 - 1900-02-16 T 0