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November 2017 Discussions & Observations Thread


Rtd208

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30 minutes ago, SnoSki14 said:

If you love storminess then that gfs run is for you, unfortunately it's a few weeks too early so we wouldn't be able to cash in on snowfall opportunities. 

Hopefully the blocking lasts a while.

You would snow with set that up , no question.

The key will be to get a PNA spike so a SW comes under a - 4/5 SD NAO sitting over Hudson Bay

No promises / But that's a big time set up.

Just need the SW to appear 

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The CFSv2 is essentially showing a scenario similar to what happened in 1959.

During the second week of November in 1959, the Arctic Oscillation plunged from a peak of +1.690 on November 8 to -4.749 on November 13. The extreme November blocking peaked on November 18 with the AO bottoming out at a November record -5.896. The lowest November temperature was 21° on November 18. This blocking episode ended on November 25. There was a short-lived strong block in the first half of December, but the month featured widespread warmth. North America’s temperature anomalies were similar to what the CFSv2 depicts.

Were AmericanWx around then, the “winter canceled” call would loudly been proclaimed across much of the subforums by mid-month. However, as things unfolded, it turned out that Scrooge did not steal the AO-. On December 25, the AO returned to negative values. It would remain negative through April 4, 1960. Winter 1959-60 wound up seeing 39.2” snow in New York City. Two big storms accounted for much of the snowfall: December 21-22, 1959 with 13.7” and March 3-4, 1960 with 14.5”.

Right now, I don’t think a December 1959 outcome is the most likely scenario. It is interesting seeing it on the CFSv2. The Euro Monthlies offer a colder outcome. At this point, I give the colder outcome approximately a 60% probability.

Finally, I have growing confidence that winter 2017-18 will likely feature far more blocking than was the case last winter. The probabilities seem tilted somewhat toward a winter with a predominantly negative AO. The potential for periods of sustained strong blocking is on the table, but it's still too soon for me to have much confidence in that idea. Having said that, I have confidence that at least one of the winter months will be very blocky (monthly AO average of -1.000 or below).

AO11092017.jpg

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3 minutes ago, LongBeachSurfFreak said:

That’s amazing and I would think would have to have positive impacts down the road. Obviously last winter was anomalous on the negative side. I would like to see what average is though before making an definite calls...

It's the highest through the 8th for the last 13 years while last year was the lowest.

 

https://www.star.nesdis.noaa.gov/smcd/emb/snow/HTML/snow_extent_plots.html

 

multisensor_4km_na_snow_extent_by_year_graph.png.43d39b95f81eb4afee53822b7176a67b.png

 

 

 

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16 minutes ago, LongBeachSurfFreak said:

That’s amazing and I would think would have to have positive impacts down the road. Obviously last winter was anomalous on the negative side. I would like to see what average is though before making an definite calls...

It's already having impacts this weekend.  This air mass solely based on temps aloft isn't insanely cold but it's holding together well as it comes southeast due to that snow cover 

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Next 8 days averaging about 44degs., or 4degs. BN.  Used 26/54 for todays inverse proceedings, since high T already acheived.

We should be -1deg. by the 18th., for the month.  Need to finish below +3.5degs., in order not to become the warmest (SON) ever.

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From the 11/10 0z GEFS, which very well illustrates how extreme the air mass now moving into the region is. The GEFS depicts 850 mb temperatures that are 3 standard deviations below normal for this time of year. As a result, NYC will smash its record low reading tomorrow and some parts of the region could see their earliest teens on record. 

 

GEFS111020170z.jpg

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This record cold is about a month ahead of schedule compared to the 2000's average in NYC. The average first day in NYC to drop to 25 degrees or lower during the 2000's is December 7th. NYC will beat the previous earliest for the 2000's by a week set on November 18th, 2014. The latest was January 4th 2016.

 

5a059b185cff8_Screenshot2017-11-10at7_19_21AM.png.2e259e4296aa5328825e11e49823e134.png

 

 

 

 

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