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November 2020 General Discussions & Observations Thread

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8 minutes ago, snowman19 said:

Yes. This La Niña is going to be right up there with the strong Ninas of 73-74, 88-89, 98-99

all snowfall duds.  The only one that delivered was 10-11 with the strong blocking that developed.

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Tomorrow should be somewhat milder. Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region.

December could see above normal temperatures redevelop during or after the first week of the month after starting off on a cool note. The possible development of a period where the AO is negative and PNA is positive could delay the warmup.

Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December, but this is no typical La Niña pattern. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance still suggest a warmer than normal December is the base case even if the first half of the month winds up near normal or even somewhat cooler than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above.  

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +2.92.

Today, the preliminary Arctic Oscillation (AO) figure was +1.345.

On November 23 the MJO was in Phase 3 at an amplitude of 0.765 (RMM). The November 22-adjusted amplitude was 0.962.

Based on the latest guidance, no significant stratospheric warming event is likely through the end of November.  

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.

Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1".

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 near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.9°.

 

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If this were summer? We'd wonder why modeling is so conservative on a band of snow and ice pellet showers racing (45 MPH?) eastward across N Central PA.  As it stands...the 18z EC is trying...  and may allow a sprinkle here and there in NYC metro between 2A-430A? We'll be sleeping and not notice if it does make it. 

 

If it was summer, it might be a band of thunderstorms. Hopefully the HRRR, which is supposed to be good at picking up convection, would have this.  Right now, I think it's lagging. I see mPing just picked up on ice pellets at State College.  Miniscule minor Fgen/WAA mainly 800-600MB.

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EURO Control for the Weeklies still has the Hudson Bay region at +10F to +25F for an entire month starting the Dec. 08, so no Arctic Air invasion is going to happen here.         Average T for the next 6 weeks is +5F,  just like last  Jan, Feb, Mar.

JB  still says get it done around here by December 15th or the 20th.         Winter ends December 21st.! 

I once again will soothe myself with the thoughts of  The Ten Day Winter,  ala Feb. 05-15  1983.       Even that failed last winter.

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30 minutes ago, CIK62 said:

EURO Control for the Weeklies still has the Hudson Bay region at +10F to +25F for an entire month starting the Dec. 08, so no Arctic Air invasion is going to happen here.         Average T for the next 6 weeks is +5F,  just like last  Jan, Feb, Mar.

JB  still says get it done around here by December 15th or the 20th.         Winter ends December 21st.! 

I once again will soothe myself with the thoughts of  The Ten Day Winter,  ala Feb. 05-15  1983.       Even that failed last winter.

DT says backloaded winter

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On 11/22/2020 at 4:28 PM, uncle W said:

I hope this year ends on a good note and we see snow for Christmas...the La ninas have seen some happy endings...it hasn't snowed except for a flurry or two on Christmas eve night since 1993's very light snow...the last good storm in that timeframe was way back in 1966...

1961...weak negative...

1962...weak negative...

1963...el nino...

1966...weak negative...

1969...el nino...

1970...la nina...

1975...la nina...

1980...weak negative...

1983...la nina...

1993...weak - to weak +

1995...la nina...

1998...la nina...

2002...el nino...

 

 

 

 

Do you remember that crazy storm on Christmas Eve in Dec 1994?  Was that actually a tropical storm making landfall at JFK after getting Fujiwhara-ed?

 

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7 hours ago, bluewave said:

It’s difficult to compare the older La Niña SST anomalies to present day due to the steady ENSO warming.

https://www.climate.gov/news-features/understanding-climate/watching-el-niño-and-la-niña-noaa-adapts-global-warming

D355ADC6-5FFF-4535-A39C-4636702230E0.jpeg.b7333a9250c3c96e083881993b7b9d0b.jpeg

 

 

 

are  we going to have to recalibrate what we consider el nino or la nina?

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6 hours ago, donsutherland1 said:

Tomorrow should be somewhat milder. Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region.

December could see above normal temperatures redevelop during or after the first week of the month after starting off on a cool note. The possible development of a period where the AO is negative and PNA is positive could delay the warmup.

Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December, but this is no typical La Niña pattern. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance still suggest a warmer than normal December is the base case even if the first half of the month winds up near normal or even somewhat cooler than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above.  

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +2.92.

Today, the preliminary Arctic Oscillation (AO) figure was +1.345.

On November 23 the MJO was in Phase 3 at an amplitude of 0.765 (RMM). The November 22-adjusted amplitude was 0.962.

Based on the latest guidance, no significant stratospheric warming event is likely through the end of November.  

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.

Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1".

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 near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.9°.

 

Don didn't Jan 2000 have a crazy weird freak snowstorm?  But it snowed in the south and rained in the north?

 

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18 hours ago, bluewave said:

NYC holding in 1st place for warmest November by a narrow margin with several more 60° days possible.

KNYC   GFSX MOS GUIDANCE  11/24/2020  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 TUE  24| WED 25| THU 26| FRI 27| SAT 28| SUN 29| MON 30| TUE 01 CLIMO
 X/N  49| 40  56| 49  62| 51  61| 51  62| 43  49| 45  56| 42  45 35 48


 

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 7
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

didn't realize 2009 was on this list, that was a classic snowy winter that comes after a mild November.

 

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The last 6 days of November are averaging 52degs.[47/57].          Making it 48degs., or +5.0.

Month to date is 52.8[+4.1].          November should end at 51.8[+4.3].

AN T's already consuming the first three days of December.        Investigate election results will ya!!!     Investigate these atmospheric models for colluding with Global Warming.

48*(60%RH) here at 6am.         51* by 10am.         54* most of the afternoon.      55* at 4pm.       53* at 5pm.      53* at 8pm.

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This may be the first time that NYC had 8 consecutive warmer than average falls.

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.
Year
Mean Avg Temperature 
Departure
2020 59.8 +2.3
2019 58.1 +0.6
2018 57.6 +0.1
2017 60.4 +2.9
2016 60.1 +2.6
2015 61.8 +3.3
2014 58.2 +0.7
2013 57.8 +0.3
2012 56.9 -0.6

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5 hours ago, LibertyBell said:

Don didn't Jan 2000 have a crazy weird freak snowstorm?  But it snowed in the south and rained in the north?

 

Yes. Raleigh picked up 20” snow, Baltimore had almost 15”, but NYC had less than 6”.

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Morning thoughts...

Today will be mostly cloudy and mild as a storm tracking to the toward the Great Lakes region brings warmer air to the East. High temperatures in the region will likely reach the middle and upper 50s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 55°

Newark: 57°

Philadelphia: 58°

An unseasonably mild Thanksgiving Day holiday lies ahead.

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Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region. There will also be some rain and showers, especially during the first half of the day.

December could start off mild before a period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December, but there is considerable uncertainty. The now likely development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month.

Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance suggest that a warmer than normal December remains the base case even if the first half of the month winds up colder than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above.  

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +5.66.

Today, the preliminary Arctic Oscillation (AO) figure was +0.705.

On November 24 the MJO was in Phase 4 at an amplitude of 0.702 (RMM). The November 23-adjusted amplitude was 0.764.

Based on the latest guidance, no significant stratospheric warming event is likely through the start of December.  

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.

Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1".

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 near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 52.1°.

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The last 5 days of November are averaging 54degs.[48/59].      Making it 50degs., or +7.0.

Month to date is  52.7[+4.1].        November should end at 52.2[+4.6].

Latest GFS run is Cold for the start of December, but snow less (clueless too?)    At any rate,  the uncorrected average is  41[38/45].         This would be a +1.0, but I would go with a corrected average of 35, or -5.0 for the first 7 days of December.     

57*(99%RH) at 6am, rain.       60* at 7am.        58* by 9am.       59* by 10am.        62* at 11:30am, but 60* at Noon.       65* at 1:30pm.      66* with some sun at 3pm.       67* at 3:15pm.        60* by 7pm.       57* by 10pm.

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1 hour ago, wdrag said:

Interesting morning midday LI/CT... possible gusts 35-45 MPH in a couple of showers/isolated thunderstorm. Sounding not quite unstable enough lower 1000 feet for better transfer.  I expect isolated thunderstorms to develop LI/CT before this ends from west to east midday-early afternoon. 

I can hear the wind whistling through the trees!

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39 minutes ago, bluewave said:

We are on track for a top 5 warmest Thanksgiving across the area. Parts of LI are already in the low 60s at 7am.

Shirley        LGT RAIN  61  55  81 S9       

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

NYC

#1....69°

#2....66°

#3....65°

#4....64°

#5....62°

Chris what was number 1?  I know number 2 was 2007.

Also do you think we'll have the top warmest November?

 

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Morning thoughts...

A storm is currently moving up the St. Lawrence River Valley. Rain and showers associated with that storm will end and the sun could return during the afternoon. It will be very mild for the season. Temperatures will likely top out in the lower and middle 60s across the area. Likely high temperatures around the region include:

New York City (Central Park): 64°
Newark: 65°
Philadelphia: 66°

The remainder of November will be generally warmer than normal.

 

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27 minutes ago, dWave said:

Rain looks mostly done already. Just an occasional shower left. Or should I excpect areas to the west to fill in? 

Can't promise but the little line near Allentown at this time may strengthen across NYC around 11A?  12z Modeling doesn't seem to capture this so i could be wrong but relying more on 06z HRDPS. 

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65° at Newark. Getting close to the record high of 68° set back in 2011.

Newark Liberty PTSUNNY   65  59  81 SW16      29.95F
Almanac for NEWARK LIBERTY INTL AP, NJ
November 26, 2020
Daily Data Observed Normal Record Highest Record Lowest
Max Temperature M 51 68 in 2011 29 in 1938
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