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November 2020 General Discussions & Observations Thread


Rtd208
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10 minutes ago, uncle W said:

the night before Kocin did say there was an outside chance the storm comes up the coast...

The satellite and radar trends the day before looked like it was coming up the coast. But all the models were OTS. Imagine if when NYC had their heaviest snowstorm in January 2016 the models all had no snow the day before. This is what happened at RDU when they got their record 20.3” on 1-25-00. 

https://projects.ncsu.edu/atmos_collaboration/nwsfo/storage/cases/20000125/

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With strong cold air advection, temperatures remained mainly in the 30s across the region today. High temperatures included:

Boston: 35°
Bridgeport: 36°
Islip: 37°
New York City: 36°
Newark: 38°
Philadelphia: 40°

In the West, Phoenix set a record high temperature of 89° (old record: 88°, 2008) and Tucson reached a record 91° (old record: 86°, 1990 and 2019).

Tomorrow will get off to a cold start, but readings should rebound to well into the 40s during the afternoon. Afterward, temperatures will continue to rapidly moderate. Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. December could see above to perhaps much above normal temperatures redevelop during the first week of the month.

The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +20.10.

Today, the preliminary Arctic Oscillation (AO) figure was +1.970.

On November 17 the MJO was in Phase 2 at an amplitude of 1.682 (RMM). The November 16-adjusted amplitude was 1.564.

Based on the latest guidance, no significant stratospheric warming event is likely through at least November 25. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter.

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region.

The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia.

Based on sensitivity analysis applied to the latest guidance, there is an implied 94% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.0°.

 

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5 hours ago, BucksCO_PA said:

Don't get me wrong that winter wasn't epic & something that'll be remembered for years however it does have it's moments. 

At Philly the 31 day period from 1/14 thru 2/13 was quite cold, -6.4 degree departure. Over that span 15.8" of snow officially at the airport, a tick or two more here locally NE of the city. What's interesting is the # of consecutive days with at least 1" of snow cover. At PHL snow depth records go back to 1948 and that winter had the 3rd longest stretch on record.

JAN/FEB 1961 - 28 days

FEB/MAR 2003 - 26 days

JAN/FEB 2000 - 23 days

Locally I finished that season with just over 24" close to average. Included an APR stat padder, throw in some bonus pts. for a double digit storm & yeah after the laundry list of dreadful outlooks I'd sign up for something similar.

Locally 37 / 31 split so far today, 37 is the coldest high temp since FEB 29th

1st freeze if not late tonight then certainly tomorrow morning at PHL, the airport will finish with a growing season of 260 days while my location 10 miles NE of the city is a dramatically different 173 days thanks to the solid May freeze.

Great post. I would definitely sign for January 2000 after last year’s debacle. 

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January 2000 was my first internet snowstorm...1999-2000 and 1965-66 were similar winters...1999-00 averaged 36.2 for Dec thru Feb...1965-66 averaged 35.9...the coldest period for 1999-00 was from 1/9-2/7 averaging 26.2...15" of snow from 1/20-2/18...1965-66 was 1/12-2/10 averaging 28.5...18" of snow from 1/26-2/25...both winters had its first measurable snow on 1/20...1999-00 was a weaker version of 1965-66...

1965-66 snow dates...1999-00

0.4" 1/20/66...............2.5" 1/20...

2.4" 1/23.....................5.5" 1/25

2.0" 1/26-27................1.5" 1/30

6.8" 1/29-30................2.2" 2/3

3.1" 2/2-3....................3.0" 2/18

0.4" 2/16.....................

6.3" 2/24-25................

 

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2 hours ago, donsutherland1 said:

With strong cold air advection, temperatures remained mainly in the 30s across the region today. High temperatures included:

Boston: 35°
Bridgeport: 36°
Islip: 37°
New York City: 36°
Newark: 38°
Philadelphia: 40°

In the West, Phoenix set a record high temperature of 89° (old record: 88°, 2008) and Tucson reached a record 91° (old record: 86°, 1990 and 2019).

Tomorrow will get off to a cold start, but readings should rebound to well into the 40s during the afternoon. Afterward, temperatures will continue to rapidly moderate. Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. December could see above to perhaps much above normal temperatures redevelop during the first week of the month.

The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +20.10.

Today, the preliminary Arctic Oscillation (AO) figure was +1.970.

On November 17 the MJO was in Phase 2 at an amplitude of 1.682 (RMM). The November 16-adjusted amplitude was 1.564.

Based on the latest guidance, no significant stratospheric warming event is likely through at least November 25. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter.

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region.

The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia.

Based on sensitivity analysis applied to the latest guidance, there is an implied 94% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.0°.

 

I didn’t see any forecast with a 36 degree high for NYC today, very impressive

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8 hours ago, bluewave said:

We may have to wait until another strong El Niño emerges to see a dominant STJ instead. Jan 16 was one of my all time favorites.

Ah that seems so long ago now.   Can always hope for some of the good fortune we had in December 2017, although it really does not look good right now.

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