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November 2019 General Discussions & Observations Thread


Rtd208
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22 minutes ago, bluewave said:

Yeah, a strong Aleutian low in November is typically found with El Niños.This time we have the much intense -EPO blocking of recent Novembers combined with it. So maybe the atmosphere will follow an El Niño progression this year. But the wild card is what the NAO does in December. The default El Niño December is mild for us. So -NAO is required for colder and snowier outcomes like 2002.The NAO has been in a positive state in December since 2011. 

5725339A-A522-4372-AF57-3E72BB0BA4A0.png.5f6426cccc3bd2f89c94ff6dbaa82548.png

 

Looking ahead at the AO forecasts next 2 weeks if that verifies it seems virtually impossible we could have a positive AO winter.  Without even looking I would guess there is at most 2 cases of a -2 or greater AO November having a Dec-Feb AO average positive

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37 minutes ago, bluewave said:

Yeah, a strong Aleutian low in November is typically found with El Niños.This time we have the much intense -EPO blocking of recent Novembers combined with it. So maybe the atmosphere will follow an El Niño progression this year. But the wild card is what the NAO does in December. The default El Niño December is mild for us. So -NAO is required for colder and snowier outcomes like 2002.The NAO has been in a positive state in December since 2011. 

Right, and that's why I find the end of the ensembles very interesting right now. But I've also seen some research suggest that there is a 7-8 year oscillation between + and - NAO winter regimes. We're about due if that's accurate.

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32 minutes ago, SnowGoose69 said:

Looking ahead at the AO forecasts next 2 weeks if that verifies it seems virtually impossible we could have a positive AO winter.  Without even looking I would guess there is at most 2 cases of a -2 or greater AO November having a Dec-Feb AO average positive

 

9 minutes ago, EasternLI said:

Right, and that's why I find the end of the ensembles very interesting right now. But I've also seen some research suggest that there is a 7-8 year oscillation between + and - NAO winter regimes. We're about due if that's accurate.

The key is actually verifying a -NAO during December. Expecting one since 2011 has been like betting against the house. Last 8 years have been the most positive December +NAO streak on record. So it will be interesting to see if this year can push back against the recent decadal pattern.

C0F6C64A-0624-45A8-87DD-AA1E3C8F0B65.png.62d5ad8b183b06fa1a9528ee983a181e.png

 

 

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20 minutes ago, bluewave said:

 

The key is actually verifying a -NAO during December. Expecting one since 2011 has been like betting against the house. Last 8 years have been the most positive December +NAO streak on record. So it will be interesting to see if this year can push back against the recent decadal pattern.

Agreed. Will be fascinating to watch everything play out. 

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5 hours ago, Snow88 said:

Way too early to say what's going to happen through December. Remember all the great winter outlooks last winter ? How did they turn out ?

Long  range is a crapshoot

Our best winter forecast skill this decade has been the timing or sequence of the monthly temperature departures. But the magnitude of those departures has been a surprise. When taking the entire OKX forecast area into account, snowfall totals have also been difficult to pin down before the season started. Maybe some years demonstrated relative success in snowfall forecasts for NYC. But the extreme totals at some places like Islip have blown past expectations of winter forecasts. Seasonal forecasts have been very poor at handling the actual extremes that defined the 2010’s.

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11 minutes ago, Brian5671 said:

I think it would be more mid-day Tuesday as the precip pulls out the stuff at night and Tue AM is rain (coast)

The Euro has something for everyone on Tuesday. Highs of 55-60 on Long Island early in the morning. Then a sharp cold front and the precipitation ending as snow during the day. Followed by near record cold Wednesday.

 

BFDFA880-4F3C-44FC-9BF0-395F9DC9B5AB.thumb.png.b8322a0edefd853bcb2044b64c3f3a27.png

5F0FBD8A-E742-4983-A244-CF9080517F46.thumb.png.11ec9659319a287b5a83bbb31919e364.png

644677DE-6352-4409-A078-22AEAA9705A9.thumb.png.3c9d10dbca6a7eec883200439ffe36c6.png

 

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most of the snowiest Decembers had a neg ao on average...out of the 20 years 14 were cold...5 la nina...6 el nino...9 neutral...13 had a neg ao...4 were positive...3 near neutral...11 neg nao...7 positive...2 neutral...12 positive pna...6 neg pna...2 neutral...9 neg qbo...9 positive...2 around neutral...

year....snowfall....big snow......ave temp....oni…...AO.......NAO....PNA....QBO...

2010.....20.1"...…….20.0"...…….32.8......-1.6....-2.631....-1.85....-1.78....10.97

2003.....19.8"...…….14.0"...…….37.6...….0.4.....0.265.....0.64.....0.86...-11.38

1960.....18.6"...…….15.2"...…….30.9...….0.1....-0.343.....0.06.....1.46...-11.36

1959.....15.8"...…….13.7"...…….38.4...….0.0....-0.042.....0.44.....0.66......8.30

2000.....13.4"...…….12.0"...…….31.1...…-0.7....-2.354....-0.58.....1.23...-14.56

2009.....12.4"...…….10.7"...…….35.9...….1.6....-3.413....-1.93.....0.34...-15.57

1995.....11.5"...……...7.9"...…….32.4...…-1.0....-2.127....-1.67.....0.92.....-4.57

1963.....11.3"...……...6.3"...…….31.2...….1.3....-1.178....-1.92....-0.08......5.48

2002.....11.0"...……...6.0"...…….36.0...….1.1....-1.592....-0.94.....1.59.....-0.50

2005...….9.7"...…......5.8"...…….35.3...…-0.8....-2.104....-0.44.....1.38...-25.04

1966...….9.1"...….…..7.1"...…….35.7...….-0.3....-1.401.....0.72.....0.09....13.26

1957...….8.7"...….…..8.0"...…….40.2...…..1.7.....0.828.....0.12....-0.43...…7.35

2013...….8.6"...….…..5.0"...…….38.5...….-0.3.....1.475.....0.95....-0.86....12.52

1961...….7.7"...….…..6.2"...…….35.5...….-0.2....-1.668....-1.48....-1.24......6.25

2017...….7.7"...….…..4.5"...…….35.0...….-1.0....-0.059.....0.88.....0.89...-18.12

1952...….7.5"...….…..4.5"...…….38.4...…..0.1....-1.827....-0.43.....0.93.....-1.65

1990...….7.2"...….…..7.2"...…….42.6...…..0.4.....1.277.....0.22....-1.32....10.68

1968...….7.0"...….…..5.2"...…….34.3...…..1.0....-0.783....-1.40....-1.44...-11.36

1993...….6.9"...….…..4.0"...…….37.3...…..0.1....-0.104.....1.56.....0.72.....-6.00

1969...….6.8"...….…..6.8"...…….33.4...…..0.6....-1.856....-0.28.....1.84......5.00

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14 minutes ago, bluewave said:

The Euro has something for everyone on Tuesday. Highs of 55-60 on Long Island early in the morning. Then a sharp cold front and the precipitation ending as snow during the day. Followed by near record cold Wednesday.

 

BFDFA880-4F3C-44FC-9BF0-395F9DC9B5AB.thumb.png.b8322a0edefd853bcb2044b64c3f3a27.png

5F0FBD8A-E742-4983-A244-CF9080517F46.thumb.png.11ec9659319a287b5a83bbb31919e364.png

644677DE-6352-4409-A078-22AEAA9705A9.thumb.png.3c9d10dbca6a7eec883200439ffe36c6.png

 

Eps is similiar

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5 hours ago, Cfa said:

Wouldn’t surprise me if today’s “warmth” over performs in some spots. Already 48 here with the sun partially obscured by clouds, forecast is 52.

Ehh, a lot cloudier than expected, so I was wrong. Temps were off to the races earlier with sunshine, we would’ve easily passed the lower 50’s had it remained sunny.

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2 hours ago, uncle W said:

most of the snowiest Decembers had a neg ao on average...out of the 20 years 14 were cold...5 la nina...6 el nino...9 neutral...13 had a neg ao...4 were positive...3 near neutral...11 neg nao...7 positive...2 neutral...12 positive pna...6 neg pna...2 neutral...9 neg qbo...9 positive...2 around neutral...

 

Yeah, only 2 solid -NAO Decembers with an El Niño since 2000. We got favorable MJO phases for a -NAO during December 2002 and 2009. Notice how the MJO mostly avoided the Maritime Continent phases. During recent Decembers, the MJO always found a way to focus in phases 4 and 5.  So the MJO will be important to track as we head into December.

2F558068-8C13-46B7-9E80-1F3590F6BE59.gif.edda754021d23913351e7e6038a2e943.gif

DA2B5367-8FDD-4E1C-AF7E-69DEBEF993B2.gif.5a5a88a2e6a162eeb1eebf90528a9880.gif

 

 

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Tomorrow will feature a very mild day for November. However, much colder air is on the way.

An unseasonably cold air mass will push into the region on Tuesday. Numerous cities in the Middle Atlantic and southern New England areas could challenge or set daily record low temperatures on Wednesday.

Select records for November 13 are:

Allentown: 18°, 1996
Baltimore: 22°, 1911
Boston: 14°, 1883
Bridgeport: 23°, 1986
Harrisburg: 21°, 1911
Islip: 24°, 2001
New York City-JFK: 25°, 1986
New York City-LGA: 26°, 1986
New York City-NYC: 24°, 1986
Newark: 24°, 1986
Philadelphia: 24°, 1996
Poughkeepsie: 16°, 2013
Scranton: 19°, 1986
White Plains: 23°, 1986
Washington, DC: 22°, 1911

The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was +0.7°C for the week centered around October 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged +0.58°C. A neutral ENSO is currently the base case for Winter 2019-20.

The SOI was -14.64 today.

An SOI reading of -30 or below, as occurred on November 4-5, also occurred during three prior years in the November 1-10 timeframe. All three cases featured a warmer than normal December. The average temperature for those three cases was 2 degrees warmer than normal.

Today, the preliminary Arctic Oscillation (AO) figure was -1.176.

Some of the more recent guidance shows the AO remaining strongly negative through the next two weeks. Such an outcome would increase prospects for at least some additional bouts of cold in the East after mid-month.

On November 9, the MJO was in Phase 6 at an amplitude of 2.566 (RMM). The November 8-adjusted amplitude was 2.534.

The MJO's move into Phase 5 at a high amplitude reinforces the idea of a warmer to perhaps much warmer than normal second half of November. Since 1974, there were 3 cases that saw the MJO in Phase 5 at an amplitude of 1.500 or above for at least 2 days during the November 1-10 period. The November 16-30 temperature averaged 46.1° (0.2° above normal). However, when the case that had a cooler than normal September was excluded, the mean temperature was 49.1° (3.2° above normal). September 2019 had a mean temperature of 70.4°, which was 2.4° above normal.

Even as the second half of November will likely experience a pattern change to generally warmer than normal conditions within a few days of November 20, the magnitude of the cold during the first half of the month has made it very likely that November will finish with a cold anomaly in the region.

In addition, the MJO has now spent two days in Phase 6 at an amplitude of 1.500 or above. That development reinforces the the idea from the strongly negative SOI earlier this month that December will be likely be warmer than normal.

Since 1974, five years saw the MJO in Phase 6 at an amplitude of 1.500 or higher for two or more days during the 1974-2018 period: 1985, 1987, 1996, 1998, and 2018. Only 1985 with a mean temperature of 34.2° was colder than normal during December. The mean temperature for those five cases was 39.7°. The 1981-2010 normal monthly temperature for New York City is 37.5°.

Based on sensitivity analysis applied to the latest guidance, New York City has an implied 78% probability of experiencing a colder than normal November.

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the earliest 20 degree or lower temperature in Central Park is 20 on 11/14/1905...the earliest date the max temperature was 32 or lower was also on 11/14 but in 1942...there is a chance NYC could break the record low on the 12th at midnight and break the record low on the 13th...there is a chance the max could be below freezing and the min 20 or below setting records for so early in the season...

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The next 8 days are averaging 40degs., or about 7degs. BN.

Month to date is  -4.2[46.8].          Should be  -5.4[43.8] by the 19th.

Big story will have to be the T, since virtually no Snow is showing for NYC.

51* here at 6am.  (unit seems pre-programed  at this T for the last 15 hours.)   53* by 8am.     57* by 11am.    58* at Noon.      59* by 2pm.       60* by 4pm.

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