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November 2020 General Discussions & Observations Thread


Rtd208
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1 hour ago, bluewave said:

The SE Ridge or war has been a factor in the last 12 out of 15 DJF winter months. The only 3 winter months that we had mean trough in the East since the super El Niño were Dec17, Feb 16, and Jan 16. Models beyond 8-10 days have reliably underestimated the ridge. We usually have to wait until about a week out for the models to show the proper strength. 

I don’t believe any model showing a -NAO in the long-range, especially the GFS. How many times over the last several years have we seen these phantom -NAO’s pop up in the long range modeling, only to completely disappear as we move forward in time? People keep falling for it. Until proven otherwise, it’s a mirage

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1 hour ago, qg_omega said:

Bluewave doesn’t seem on board with the December optimism

I don’t think December 2010 is walking through the door but I feel optimistic for some snow in December. 
 

1. the Pv isn’t going to sit in Ak

2. The pna willbe positive with the potential for some blocking 

3. Once into mid December the above normal temps in Canada are below normal here. 
 

 

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With sunshine that persisted into the afternoon, temperatures rose well into the 60s in much of the region. Tomorrow will be cooler under mainly cloudy skies. Showers are likely. A steadier rain could develop later in the day or at night.

Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. One such cool shot is likely early next week. 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 +2.86.

Today, the preliminary Arctic Oscillation (AO) figure was +3.262.

On November 20 the MJO was in Phase 2 at an amplitude of 1.401 (RMM). The November 19-adjusted amplitude was 1.581.

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 99% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.2°.

The implied probability for a November mean temperature of 50.0° in Central Park is now approximately 81%. Since 1869, there have been 19 cases where November had a mean temperature of 50.0° or above. 14/19 (74%) went on to have a warmer than normal December, including 9/19 (47%) with a December mean temperature of 40.0° or above (2.5° or more above normal). The winter mean temperature for those 14 cases was 37.5° (2.2° above normal). The winter mean temperature for the subset of December cases with a mean temperature of 40.0° or above was 38.9° (3.6° above normal) and four of those cases wound up having an average winter temperature of 40.0° or above.

 

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On 11/17/2020 at 3:56 PM, bluewave said:

Yeah, the 8-4-15 macroburst was one of our more impressive severe events for so early in the day.

https://www.weather.gov/okx/storm08042015


0502 AM     TSTM WND GST     1 WSW SOUTH SETAUKET    40.91N  73.12W
08/04/2015  E74 MPH          SUFFOLK            NY   MESONET         

            95 MPH GUST MEASURED ON ROOF OF STONY BROOK HEALTH 
            SCIENCES TOWER. 

Cool.  I never saw the LSR before because we had no power for a couple of days.  Two of those storm reports are from within a block or two of here.  It was quite a scary wakeup alarm.  It sounded like rocks being blasted at the house which I took to be hail, but some of it was branches blown out of trees.

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The next 8 days are averaging 52degs.[47/57].         Making it 47degs., or +4.0.

Month to date is 53.3[4.1].           Should be 51.6[+4.1] by the 30th.

W/O the correction I always apply, this would be the warmest November ever.      We could gain 40 degrees worth of  surplus and thus another 40/30 = +1.3.      It actually indicates 6 more 60-Degree Days are possible by months end.

First week of December seems to have too many vortices around the EC at the same time.

47*(57%RH) here at 6am.     46* at 7am.      50* at 9am.        54* by Noon.        55* by 4pm, but most of the PM was at 52*.       56* at 6pm.     57* at 10pm.     58* at 11pm.

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It looks like the CONUS is on track for a top 5 warmest November. Numerous stations are in 1st place with just under 10 days to go. Pretty uniform warmth across the country.


 

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Nov
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Mean Avg Temperature 
Missing Count
1 2020 53.3 9
2 2015 52.8 0
3 2001 52.7 0
4 1979 52.5 0
5 1948 52.4 0
6 1975 52.3 0
7 2011 51.9 0
- 2006 51.9 0
- 1994 51.9 0
- 1931 51.9 0
8 1902 51.4 0
9 2009 51.1 0
10 1999 50.8 0


 

Time Series Summary for Chicago Area, IL (ThreadEx) - Month of Nov
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Mean Avg Temperature 
Missing Count
1 2020 50.2 9
2 1931 50.0 0
3 1909 48.5 0
4 2001 48.2 0
5 1913 47.2 0

 

Time Series Summary for Goodland Area, KS (ThreadEx) - Month of Nov
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Mean Avg Temperature 
Missing Count
1 2020 48.9 9
2 1999 46.4 0
3 1914 46.0 0
4 1949 45.7 0
5 2016 45.5 0

 

BE7C0EB3-1026-4A0F-8DD9-1BAED3F2C258.thumb.png.be8464d3bacb2d9cb6c2a037f68c66d9.png

77A62142-76D8-4AE4-A61B-57F3FFFE93DD.thumb.png.1ce113da9ddc6f0d04ee10201d47fee3.png

 

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Morning thoughts...

At 8:35, rain and snow was falling in northern Pennsylvania along a warm front associated with a storm that will be tracking north and west of the region. Rain was falling in part of the Ohio Valley and light snow was falling in Detroit.

Today will be another mostly cloudy. Showers will become increasingly likely during the afternoon and evening. Steadier rain will likely arrive tonight. High temperatures in the region will likely reach the lower and middle 50s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 55°

Newark: 57°

Philadelphia: 58°

A brief shot of cooler air is likely Tuesday into Wednesday.

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On 11/17/2020 at 9:11 AM, dWave said:

I think the NWS didn't consider that night sufficient enough to end the growing season throughout the 5 boros.  Just touching 32 for a few mins deep in Central Park while the sun is coming up didn't do much harm overall in NYC.  Staten Island and a few isolated neighborhoods elsewhere being the exception. 

it also hit 32 at JFK and the temp was exactly 0.0 C in my urbanized part of SW Nassau County a few miles SE of JFK on Oct 31.

 

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19 hours ago, Allsnow said:

I might be in the minority but I feel the cutter/hugger track the last few years is more of a cause of the -pna then ENSO state 

yes same thing happened in the late 80s/early 90s...enso didnt matter we got cutter/hugger regardless.  If it wasnt that the storms missed us out to sea or to our south lol.  It sounds like the last few years....

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On 11/21/2020 at 7:59 AM, bluewave said:

We are going to need a strong enough El Niño in coming years to change up this entrenched La Niña background state. Very persistent Great Lakes and coastal hugger storm tracks in recent years. Notice how both the Euro and GFS  have another strong cutter near the end of November.

35CFCA17-EC84-482C-80FF-AE877D32E630.thumb.png.0edd292fe99b685fd4c66a21c7ae1879.png

325A780C-E6A0-41B2-AEC4-81AFBD511633.thumb.png.ad21e528a0966ae380c2520e569b2d38.png

 

on the other hand, some of our strongest el ninos have been snowless a la 1997-98

 

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NYC could see only the 5th 60° Thanksgiving since 1999.

 

KNYC   GFSX MOS GUIDANCE  11/22/2020  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 SUN  22| MON 23| TUE 24| WED 25| THU 26| FRI 27| SAT 28| SUN 29 CLIMO
 X/N  54| 50  55| 38  49| 36  52| 51  64| 50  58| 52  57| 49  54 35 48

https://www.weather.gov/media/okx/Climate/CentralPark/Thanksgivingwx.pdf

11-26-15...60°

11-22-07...66°

11-25-04...65°

11-25-99...61°
 

https://www.weather.gov/media/okx/Climate/CentralPark/Top5Thanksgiving.pdf

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20 minutes ago, bluewave said:

NYC could see only the 5th 60° Thanksgiving since 1999.

 


KNYC   GFSX MOS GUIDANCE  11/22/2020  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 SUN  22| MON 23| TUE 24| WED 25| THU 26| FRI 27| SAT 28| SUN 29 CLIMO
 X/N  54| 50  55| 38  49| 36  52| 51  64| 50  58| 52  57| 49  54 35 48

https://www.weather.gov/media/okx/Climate/CentralPark/Thanksgivingwx.pdf

11-26-15...60°

11-22-07...66°

11-25-04...65°

11-25-99...61°
 

https://www.weather.gov/media/okx/Climate/CentralPark/Top5Thanksgiving.pdf

1999 appears to be a strong analog for both the east and west coast

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On 11/21/2020 at 7:59 AM, bluewave said:

We are going to need a strong enough El Niño in coming years to change up this entrenched La Niña background state. Very persistent Great Lakes and coastal hugger storm tracks in recent years. Notice how both the Euro and GFS  have another strong cutter near the end of November.

35CFCA17-EC84-482C-80FF-AE877D32E630.thumb.png.0edd292fe99b685fd4c66a21c7ae1879.png

325A780C-E6A0-41B2-AEC4-81AFBD511633.thumb.png.ad21e528a0966ae380c2520e569b2d38.png

 

if we get a moderate or strong el nino next year it may eat into what was set to be another baking hot summer following in the 11 yr cycle.  The summers in the 11 yr cycle that haven't been extremely hot (but still had periods of extreme heat) were all developing el ninos.  Then again so was 2002.....

 

 

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18 minutes ago, bluewave said:

We usually have to wait until early to mid-December for the models to catch on to the overall December pattern. I think that this is due to the 2nd half of the month warming at a much faster rate than the first half. So the early December patterns usually aren’t representative of the means for the whole month averaged out. This seems to fit with the big warm that up we have experienced most years near the solstice. 2013 was a classic example of this. NYC had 5.0” of snow on 12-14 and 71° on 12-22.

60E0CA55-B63F-454E-A763-29A04086AB43.thumb.jpeg.32898d858a348b6523912a5725fbbeba.jpeg
03BD3FB2-67E5-4C23-B23F-3B78384DDC96.thumb.jpeg.fe733f3dc2aace95aec5a4d73ec30281.jpeg

Im more referring to the winter as a whole. The last two winters whatever pattern set up at the end of December has dominated throughout the winter. This year seems reversed so far, with a warm November and early start to December. 
 

Now do we get a reverse in the second half of the month? The PV is very strong currently, this time last year it was weak and on the verge of a ssw. At the end of December 2018 the Pv took off and pretty much closed the shades on any snow potential.

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3 hours ago, bluewave said:

We usually have to wait until early to mid-December for the models to catch on to the overall December pattern. I think that this is due to the 2nd half of the month warming at a much faster rate than the first half. So the early December patterns usually aren’t representative of the means for the whole month averaged out. This seems to fit with the big warm that up we have experienced most years near the solstice. 2013 was a classic example of this. NYC had 5.0” of snow on 12-14 and 71° on 12-22.

60E0CA55-B63F-454E-A763-29A04086AB43.thumb.jpeg.32898d858a348b6523912a5725fbbeba.jpeg
03BD3FB2-67E5-4C23-B23F-3B78384DDC96.thumb.jpeg.fe733f3dc2aace95aec5a4d73ec30281.jpeg

Remember that..and two days later we had snow showers Christmas eve

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