November 2020 General Discussions & Observations Thread

[donsutherland1]

In a day filled with sunshine, the temperature soared into the 60s across much of the region today. 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 +16.86.

Today, the preliminary Arctic Oscillation (AO) figure was +3.144.

On November 19 the MJO was in Phase 2 at an amplitude of 1.579 (RMM). The November 18-adjusted amplitude was 1.551.

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 98% 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 near 80%. 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.

 

[CIK62]

The next 8 days are averaging 51degs.[45/56].         Making it 46degs., or +3.0.

Month to date is 53.2[+3.8].          Should be 51.1[+3.6] by the 29th.

Last two days of November are now switched to AN, after a recount.  lol!

EURO Weeklies greet Winter with 11 straight days in the 60's.

EURO Control outlook for December is a warning to 12/2015----Look Out!----I am gunning for you.

55*(54%RH) here at 6am.     54* at 7am.      60* by 11am.       62* by Noon.        63* at 1pm.        60* by 4pm.       It clouded up after 1pm and T went no further.      54* by 9pm.

[bluewave]

NYC on track for a top 10 warmest November. Models have generally above normal temperatures for the remainder of the month. Today looks like the 2nd day in a row to reach 60°.

KNYC   GFSX MOS GUIDANCE  11/21/2020  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 SAT  21| SUN 22| MON 23| TUE 24| WED 25| THU 26| FRI 27| SAT 28 CLIMO
 X/N  60| 42  53| 48  55| 36  48| 40  55| 48  58| 43  54| 44  54 36 49

 

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	53.2	10
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

 

[snowman19]

33 minutes ago, bluewave said:

NYC on track for a top 10 warmest November. Models have generally above normal temperatures for the remainder of the month. Today looks like the 2nd day in a row to reach 60°.

KNYC   GFSX MOS GUIDANCE  11/21/2020  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 SAT  21| SUN 22| MON 23| TUE 24| WED 25| THU 26| FRI 27| SAT 28 CLIMO
 X/N  60| 42  53| 48  55| 36  48| 40  55| 48  58| 43  54| 44  54 36 49

 

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	53.2	10
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

 

Looks like a rather intense period of La Niña strengthening coming up. Easterlies are going to be ripping, regions 3.4 and 4 still very cold and dropping. This is going to limit how far east any MJO wave can make it, the cold waters and very strong easterlies are going to shear it apart

[donsutherland1]

Morning thoughts...

Today will be another mostly sunny and mild day. High temperatures in the region will likely reach the lower 60s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 61°

Newark: 63°

Philadelphia: 64°

Tomorrow will be somewhat cooler and there could showers.

[KEITH L.I]

30 minutes ago, 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.

 

At least there's a trough in the east and ridge in the west lol..GFS long range looks stormy in the east,probably rainstorms but at least it's not 60 and sunny in early December

[Allsnow]

59 minutes ago, KEITH L.I said:

At least there's a trough in the east and ridge in the west lol..GFS long range looks stormy in the east,probably rainstorms but at least it's not 60 and sunny in early December

Yeah, I don’t think we had a ridge spike like that in the west for years.

[Allsnow]

Looks like a active STJ and +pna to start December. We could have a chance with that set up

[bluewave]

1 hour ago, KEITH L.I said:

At least there's a trough in the east and ridge in the west lol..GFS long range looks stormy in the east,probably rainstorms but at least it's not 60 and sunny in early December

Remarkably consistent storm track since 2018 with 3 of the wettest years on record for higher elevations to our SW.

Time Series Summary for HIGHLANDS, NC - Jan through Dec
Click column heading to sort ascending, click again to sort descending.

Rank	Year	Total Precipitation	Missing Count
1	2020	125.89	42
2	2018	125.46	0
3	1979	115.92	37
4	2019	111.78	0

 

[Rjay]

My forecasted high 2 days ago for today was 59.   Yesterday the forecast for today was 62.   It's 65 currently.  

[qg_omega]

16 minutes ago, Rjay said:

My forecasted high 2 days ago for today was 59.   Yesterday the forecast for today was 62.   It's 65 currently.  

More sun then expected

[Stormlover74]

Upton going with a high near 60. Currently 64

[Stormlover74]

Nope

Highs today will top out in the mid 50s to lower 60s. Stayed on the higher end of the guidance based on recent performance.

[Brian5671]

66 here

[donsutherland1]

Temperatures are running well above the guidance. Central Park will likely reach the middle 60s and Newark will be in the upper 60s to near 70.

[Stormlover74]

Clouds starting to filter in now. Temps probably start leveling off

[Intensewind002]

High of 65F right now, the forecast was for 60 here

[Cfa]

68 here. Picture perfect.

[CIK62]

Courtesy of WeatherBell.   

Very Ugly Look for a 46 Day interval.     Records are gonna fall if this holds up.    Hey, lets process this through a malfunctioning Star Trek Transporter and maybe we could get the inverse----if you remember that episode. 

 

C

 

 

 

 

 

 

[Allsnow]

This would be fun if true . This is a niño look in a Niña ENSO lol 

[Allsnow]

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 

[binbisso]

14 minutes ago, Allsnow said:

This would be fun if true . This is a niño look in a Niña ENSO lol 

Yeah most Mets and others keep saying that this Nina is coupled with the atmosphere but obviously that is not the case as we typically would have a colder than normal November and December. Last year we had a Nino  but November and most of December played out like a nina. clearly something's up  between enso and the atmosphere.   if this map plays out That's a classic nino positive PNA negative N A O Negative a o. 

[Allsnow]

12 minutes ago, bluewave said:

We even had the cutter, hugger, southern stream suppression storm track with the +PNA during December and January 2018-2019. Notice the SE Ridge +PNA pattern. You can see that stubborn Niña ridge north of Hawaii with the fast Pacific flow. Our biggest snow event during this period was the famous whiteout snow squall at the end of a January.

That map doesn’t look like a +pna to me. It’s tough to tell with the hgt lines but doesn’t look like it. I don’t see any downstream trough in the east. Unless you’re talking about some garbage hgt rise in the west.
 

I don’t recall +pna in December 18 or January 2019. We had a dateline ridge with a -pna. I remember we had blocking in early December that produced a snowstorm north/west. January 2019 we had recorded breaking warmth with a southeast ridge and -pna combo.
 

March 2018 we had a snowy weekend with a -pna/-epo combo. 

[Allsnow]

Just now, bluewave said:

The PNA was positive in Dec 18 and Jan 19. It shifted negative for Feb 19. 
 

2018   0.40  -1.03  -0.89  -0.91  -1.34   0.51  -0.37   1.27   1.44   0.21   0.24   0.86
2019   0.83  -1.08   0.25  -0.61  -0.29   0.12   1.11   1.18   2.00  -1.02  -0.06   0.18
2020  -0.24   0.17  -2.17  -1.18   0.21   0.70   1.73   1.82   0.75  -1.13

That flow was still basically from Seattle or southern BC off a flat ridge. Not exactly a ideal pna rise for us. 

[Allsnow]

31 minutes ago, binbisso said:

Yeah most Mets and others keep saying that this Nina is coupled with the atmosphere but obviously that is not the case as we typically would have a colder than normal November and December. Last year we had a Nino  but November and most of December played out like a nina. clearly something's up  between enso and the atmosphere.   if this map plays out That's a classic nino positive PNA negative N A O Negative a o. 

This is why I think 11/12 is a bad analog. We are not getting a typical Niña response and the PV might weaken for the second half of the winter. 

[Allsnow]

Just now, bluewave said:

The last time we had a teleconnection pattern which could be considered ideal was in March 2018.

That’s all I’m really alluding to. Yes, as you said we had a tiny ridge for those months but the flow was split  still kind of zonal at h5.

[Allsnow]

Looks like a cold shot to start December after whatever storm goes by to end November 

[Allsnow]

5 minutes ago, Allsnow said:

Definitely more trending towards the GEFS today 

 

[snowman19]

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

[donsutherland1]

Under sunshine that last into the early afternoon, the temperature soared to 64° at Central Park. At the New York Botanical Garden, most of the leaves are now down. Three photos from this afternoon: