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Rtd208

November 2017 Discussions & Observations Thread

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23 minutes ago, uncle W said:

1996 was one of the exceptions that had a negative ao and nao in December with nothing to show for it...November 1996 was cold...

Decembers with an ao and nao -1 or lower...

year.....ao.....nao.....

1950...-1.928.....-1.02...snow 12/27...

1961...-1.668.....-1.48...snow 12/24

1963...-1.178.....-1.92...snow 12/23

1976...-2.074.....-1.60...snow 12/26

1995...-2.127.....-1.67...snow 12/20

1996...-1.721.....-1.41...no snow...

2009...-3.413.....-1.93...snow 12/20

2010...-1.749.....-1.85...snow 12/27

1996 was the only December that was mild without measurable snow in NYC...

the pna was negative in 12/96...positive in 12/95...

further review shows 2010 with a very negative pna...it was close to neutral the time of the blizzard on the 27th...1961 had a negative pna most of the month...

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51 minutes ago, bluewave said:

It could have been a great December if the Pacific wasn't so unfavorable.

 

 

Yes. It was -NAO too. The -PNA/+EPO ruined it like you said. 

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5 minutes ago, snowman19 said:

Yes. It was -NAO too. The -PNA/+EPO ruined it like you said. 

Sometimes the Pacific just doesn't wan't to play ball.

 

96.png.e8840bee71fec4e59e8c78ba61a06e43.png

 

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2 minutes ago, bluewave said:

Sometimes the Pacific just doesn't wan't to play ball.

 

96.png.e8840bee71fec4e59e8c78ba61a06e43.png

 

That actually was a pretty good month not far from the Coastal Plain.  I was a Junior in HS at the time in Ridgefield, Ct. and we had two storms within a 3 day period that produced 4-6" of snow.  Both were rain -> snow deals.  Further inland got significantly more.  That was the famous first Jim Cantore thundersnow shot (which as been since replicated several times) from Worcester, Ma.

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32 minutes ago, bluewave said:

Sometimes the Pacific just doesn't wan't to play ball.

 

96.png.e8840bee71fec4e59e8c78ba61a06e43.png

 

My memory of the 96-97 winter as whole is that it was sort of a reverse 93-94 and 14-15. Every indice argued the winter should have been cold or at least near normal but it wasn't  

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1 hour ago, danstorm said:

That actually was a pretty good month not far from the Coastal Plain.  I was a Junior in HS at the time in Ridgefield, Ct. and we had two storms within a 3 day period that produced 4-6" of snow.  Both were rain -> snow deals.  Further inland got significantly more.  That was the famous first Jim Cantore thundersnow shot (which as been since replicated several times) from Worcester, Ma.

We had several legit nor’easters that winter. I remember one specifically that was close on the island. We switched from moderate rain to heavy heavy parachutes that gave a slushy coating. Some of the heaviest snow I have ever seen. As soon as the precip intensity dropped it went back to and stayed rain. Had it been a few degrees colder it would have been a solid snow storm.

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14 minutes ago, uncle W said:

96-97 had major snow chances in early December and March 31st...both times temperatures were above freezing and the city got mostly rain..

Yes that was the April fools day storm which had a crazy gradient. Nyc was basically all rain, coastal westchester and SW CT was around 5-6”, just 10 or so miles inland at Armonk was around13” and another 10 or so miles at Yorktown was around 18”. Pretty sharp to say the least.

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Record Heat on Tap for Phoenix/Southwest…

Today’s preliminary Arctic Oscillation (AO) value was -3.582. That figure, if finalized, would surpass the November 21 daily record low AO reading of -3.357, which was set in 1985. The only other November 21 cases with AO values of -3.000 or below occurred in 1950 (-3.113) and 1959 (-3.239). The kind of very strong blocking that is present at this time of year has typically provided a good indication that the following winter would feature blocking (often with at least one month with an average AO figure of -1.000 or below). The return of Atlantic blocking for winter 2017-18 would be a big change from the near absence of such blocking during winter 2016-17.

Perhaps the biggest weather story in the United States will be the extreme heat that will build across the Desert Southwest in coming days. The forecast high temperatures for Phoenix (11/21 12z MOS) are as follows:

November 22: 89° (Record: 89°, 1950)
November 23: 91° (Record: 87°, 1950) **Possible latest 90° reading on record**
November 24: 89° (Record: 88°, 1950)
November 25: 88° (Record: 88°, 1950)
November 26: 86° (Record: 87°, 2014)

Latest 90° reading on record: November 15, 1999: 90°

Two years had extended outbreaks of extreme heat at this time of year that approached the magnitude of that forecast for Phoenix. Those years were 1933 and 1950. After a very warm December across the CONUS, winter 1933-34 would shift dramatically. The outcome would be much above normal snowfall in much of the eastern United States and outbreaks of extreme cold. In contrast, December 1950 was very cold across the eastern third of the United States except for parts of New England. That winter underwent a dramatic change to warmer than normal conditions that prevailed, on average, through January and February. Snowfall wound up being much below normal, especially on the coastal plain. Seasonal snowfall totals included:

Baltimore: 6.2”
Boston: 29.7”
Bridgeport: 13.7”
New York City: 11.6”
Newark: 10.9”
Philadelphia: 4.6”
Poughkeepsie: 40.8”
Washington, DC: 10.2”

Currently, the CFSv2 is forecasting temperature anomalies that are closer to those of December 1933 than December 1950. However, the Middle Atlantic and New England regions are trending colder. Based on the idea that there will be blocking during parts of December, a colder solution in the Northeast still appears somewhat more likely than a warmer one.

During winter 1933-34, the PDO turned positive.

October-March 1933-34:
October 1933: -1.19
November 1933: +0.55
December 1933: -1.10
January 1934: +0.17
February 1934: +0.68
March 1934: +1.34

During winter 1950-51, the PDO remained strongly negative to negative:

October-March 1950-51:
October 1950: -1.36
November 1950: -2.46
December 1950: -0.76
January 1951: -1.54
February 1951: -1.06
March 1951: -1.90

La Niña-PDO+ winters tend to have above to much above normal snowfall in the eastern United States. La Niña-PDO- winters tend to have below to much below normal snowfall in that region. Winter 2010-11 was an exception to the La Niña-PDO- relationship with much above normal snowfall courtesy of extreme blocking that predominated from roughly mid-December to mid-January. Once the blocking ended, there was very little additional snowfall going forward. Winter 2017-18 is likely to see the PDO closer to neutral than was the case for winter 1950-51 (possibly somewhat positive). Therefore, I continue to believe that snowfall across the Middle Atlantic and New England regions should be much higher than it was during winter 1950-51 with much of the region seeing above normal snowfall. Should strong blocking redevelop in December and the winter turn out to feature abundant strong blocking, the potential for much above normal snowfall would be on the proverbial table.

CFSv211212017.jpg

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2 hours ago, bluewave said:

All that I remember about that winter was that it was my first on the internet and had no snowstorms to track. I kept wishing that I got online a year earlier for the epic 95-96 winter. Really got started tracking the patterns once online and enjoyed reading the legendary Walt Drag long range AFD's.

We had a surprise event in early January that ended up a 2 to 4" localized event. 

http://www.raymondcmartinjr.com/weather/1997/11-Jan-97.html

 

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Models shifted to a less cold pattern over the next 10 days than they were showing over the last week or so. This is probably a result of the MJO becoming more active again with the fast Pacific flow.

 

eps_t2ma_d5_noram_120.thumb.png.e7914c673a2061864825684e0798481e.png

eps_t2ma_d5_noram_240.thumb.png.251d1ec580de119011a18bffcf711672.png

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52 minutes ago, bluewave said:

Models shifted to a less cold pattern over the next 10 days than they were showing over the last week or so. This is probably a result of the MJO becoming more active again with the fast Pacific flow.

 

eps_t2ma_d5_noram_120.thumb.png.e7914c673a2061864825684e0798481e.png

eps_t2ma_d5_noram_240.thumb.png.251d1ec580de119011a18bffcf711672.png

Verbatim it looks as though it’s showing a less -AO pattern then it had been. As anomolies aren’t as extreme up north.

i would prefer to allow the arctic to cool for a bit and then have the cold dislodge when we get into “our” snow season. Right now any cold is essentially a waste. 

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8 minutes ago, LongBeachSurfFreak said:

Verbatim it looks as though it’s showing a less -AO pattern then it had been. As anomolies aren’t as extreme up north.

i would prefer to allow the arctic to cool for a bit and then have the cold dislodge when we get into “our” snow season. Right now any cold is essentially a waste. 

This will be one of those unusual occasions when the coldest November temperatures in NYC come during the first half of November instead of the second. 

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11 minutes ago, bluewave said:

This will be one of those unusual occasions when the coldest November temperatures in NYC come during the first half of November instead of the second. 

Another factor in the upcoming pattern is the WPO going strongly positive 

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5 minutes ago, snowman19 said:

Another factor in the upcoming pattern is the WPO going strongly positive 

It will be interesting to see how or if the rapid Nino 1+2 spike affects the pattern. Some of the models are showing increasing convection over the extreme EPAC next week to 10 days. Kind of a confused look with suppressed convection over the CPAC and enhanced EPAC.

 

nino12.png.352c628b71dddc1a0416b69e32fd585a.png

 

gfs-ens_apcpna_npac_10.thumb.png.77ebe8ebd85e24e506bfda4eac86e48d.png

 

 

 

 

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14 minutes ago, Snow88 said:

CFS is now showing a cold winter

It was showing a blowtorch lol

FB_IMG_1511359071434.jpg

Next run it’ll be back to a blowtorch. Horrific model, hands down the worst of all time

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2 minutes ago, snowman19 said:

Next run it’ll be back to a blowtorch. Horrific model, hands down the worst of all time

it's prone to wild swings, that's for sure.  Remind me of the NAM's 6 hour massive changes...terrible model.

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This morning, the preliminary value of the Arctic Oscillation (AO) was -3.205. The record low value for November 22 remains -3.463, which was established in 1985.

Recent runs of the EPS and GEFS have shifted toward a warmer opening in December. However, there remains considerable uncertainty. For example, there is a cluster of ensemble members that suggest the redevelopment of strong Atlantic blocking (AO between -3.000 and -2.000) in the extended range coupled with the development of a positive PNA. Such a setup could increase prospects for the development of a trough where the EPS and GEFS currently show somewhat above normal height anomalies in eastern North America. Prospects of below normal temperatures in the eastern quarter to third of the U.S. (along with southern Ontario and southern Quebec) would also increase. December 1-7, 1985 provides an example of such a scenario. An exception is presented by December 1-7, 1991 where much of the East Coast was warmer than normal with cold anomalies locked up in Canada. The 11/22 0z run of the GFS forecast the development of a trough in the East late in the first week of December with cold anomalies developing early in the second week of December.  The 6z run featured a transient trough in the East during the first week of December along with cooler than normal readings for much of that week.  

In sum, there is a lot of uncertainty concerning the first week of December. Even with the EPS and GEFS favoring a somewhat warmer than normal first week of December as a whole, there remain plausible alternative outcomes. Much will depend on whether strong Atlantic blocking redevelops in combination with a positive PNA.

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20 minutes ago, donsutherland1 said:

This morning, the preliminary value of the Arctic Oscillation (AO) was -3.205. The record low value for November 22 remains -3.463, which was established in 1985.

Recent runs of the EPS and GEFS have shifted toward a warmer opening in December. However, there remains considerable uncertainty. For example, there is a cluster of ensemble members that suggest the redevelopment of strong Atlantic blocking (AO between -3.000 and -2.000) in the extended range coupled with the development of a positive PNA. Such a setup could increase prospects for the development of a trough where the EPS and GEFS currently show somewhat above normal height anomalies in eastern North America. Prospects of below normal temperatures in the eastern quarter to third of the U.S. (along with southern Ontario and southern Quebec) would also increase. December 1-7, 1985 provides an example of such a scenario. An exception is presented by December 1-7, 1991 where much of the East Coast was warmer than normal with cold anomalies locked up in Canada. The 11/22 0z run of the GFS forecast the development of a trough in the East late in the first week of December with cold anomalies developing early in the second week of December.  The 6z run featured a transient trough in the East during the first week of December along with cooler than normal readings for much of that week.  

In sum, there is a lot of uncertainty concerning the first week of December. Even with the EPS and GEFS favoring a somewhat warmer than normal first week of December as a whole, there remain plausible alternative outcomes. Much will depend on whether strong Atlantic blocking redevelops in combination with a positive PNA.

 

 

Thank you Don.

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51 minutes ago, donsutherland1 said:

This morning, the preliminary value of the Arctic Oscillation (AO) was -3.205. The record low value for November 22 remains -3.463, which was established in 1985.

Recent runs of the EPS and GEFS have shifted toward a warmer opening in December. However, there remains considerable uncertainty. For example, there is a cluster of ensemble members that suggest the redevelopment of strong Atlantic blocking (AO between -3.000 and -2.000) in the extended range coupled with the development of a positive PNA. Such a setup could increase prospects for the development of a trough where the EPS and GEFS currently show somewhat above normal height anomalies in eastern North America. Prospects of below normal temperatures in the eastern quarter to third of the U.S. (along with southern Ontario and southern Quebec) would also increase. December 1-7, 1985 provides an example of such a scenario. An exception is presented by December 1-7, 1991 where much of the East Coast was warmer than normal with cold anomalies locked up in Canada. The 11/22 0z run of the GFS forecast the development of a trough in the East late in the first week of December with cold anomalies developing early in the second week of December.  The 6z run featured a transient trough in the East during the first week of December along with cooler than normal readings for much of that week.  

In sum, there is a lot of uncertainty concerning the first week of December. Even with the EPS and GEFS favoring a somewhat warmer than normal first week of December as a whole, there remain plausible alternative outcomes. Much will depend on whether strong Atlantic blocking redevelops in combination with a positive PNA.

 

 

Thank you Don. I look forward to December. It's all about learning from the experience.

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The fast Pacific flow and MJO going through the milder phases should limit the amount of cold air over the next 10 days or so. So this will be the first time since 2012 that the coldest November temperature in NYC was before the 15th.

 

NEW YORK CITY-CENTRAL PARK
 KNYC   GFSX MOS GUIDANCE  11/22/2017  1200 UTC                       
 FHR  24  36| 48  60| 72  84| 96 108|120 132|144 156|168 180|192      
      THU 23| FRI 24| SAT 25| SUN 26| MON 27| TUE 28| WED 29|THU CLIMO
 N/X  33  48| 36  52| 44  55| 39  48| 32  49| 42  55| 46  52| 41 36 49

 

ECMF_phase_51m_small.gif.5a6d9a89b54ef12167fd7b656eda7808.gif

 

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3 minutes ago, bluewave said:

The fast Pacific flow and MJO going through the milder phases should limit the amount of cold air over the next 10 days or so. So this will be the first time since 2012 that the coldest November temperature in NYC was before the 15th.

 

NEW YORK CITY-CENTRAL PARK
 KNYC   GFSX MOS GUIDANCE  11/22/2017  1200 UTC                       
 FHR  24  36| 48  60| 72  84| 96 108|120 132|144 156|168 180|192      
      THU 23| FRI 24| SAT 25| SUN 26| MON 27| TUE 28| WED 29|THU CLIMO
 N/X  33  48| 36  52| 44  55| 39  48| 32  49| 42  55| 46  52| 41 36 49

 

Models keep going back and forth that remains to be seen about the amount of cold air.

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