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Pattern November Knock-Out

GaWx said:
Browsing this forum's Dec of 2016 posts, there was similar optimism with similar ENSO, which one might think is a cause for concern that we're being too optimistic. However, the AO/NAO were horrible (AO was very strongly positive 12/10-31 and the QBO was strongly positive). We have about the opposite QBO. Further to the above, I just looked at the updated GEFS based AO 2 week forecast. It is trending back to more solidly negative:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
Click to expand...

Yeah, if we can get the MJO &/or a slow moving CCKW to make a run thru the Pacific (phases 6-8) in/around mid December that would send the NAO/AO tanking once again/even more so & would aid in forcing a ridge over the Canadian Rockies (+PNA) just in time for the holiday season...
 
Webberweather53 said:
Yeah, if we can get the MJO &/or a slow moving CCKW to make a run thru the Pacific (phases 6-8) in/around mid December that would send the NAO/AO tanking once again/even more so & would aid in forcing a ridge over the Canadian Rockies (+PNA) just in time for the holiday season...
Click to expand...
Webberweather53 said:
Yeah, if we can get the MJO &/or a slow moving CCKW to make a run thru the Pacific (phases 6-8) in/around mid December that would send the NAO/AO tanking once again/even more so & would aid in forcing a ridge over the Canadian Rockies (+PNA) just in time for the holiday season...
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You guys are getting me excited. Love the Positive optimism. Carry on....
 
0z Euro is showing a good shot at some snow for the mountains of far eastern TN and western NC starting on the 1st into the 2nd. 2-6" of snowfall. If that comes true, the ski resorts in NC are going to be happy!
 
GaWx said:
Browsing this forum's Dec of 2016 posts, there was similar optimism with similar ENSO, which one might think is a cause for concern that we're being too optimistic. However, the AO/NAO were horrible (AO was very strongly positive 12/10-31) and the QBO was strongly positive. We have about the opposite QBO. Further to the above, I just looked at the updated GEFS based AO 2 week forecast. It is trending back to more solidly negative:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
Click to expand...
Seems like it tends to repeat easier when it tanks. This certainly won't hurt when looking for a winter storm next month.
 
GaWx said:
Browsing this forum's Dec of 2016 posts, there was similar optimism with similar ENSO, which one might think is a cause for concern that we're being too optimistic. However, the AO/NAO were horrible (AO was very strongly positive 12/10-31) and the QBO was strongly positive. We have about the opposite QBO. Further to the above, I just looked at the updated GEFS based AO 2 week forecast. It is trending back to more solidly negative:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
Click to expand...

Very nice catch.


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whatalife said:
Very nice catch.


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Click to expand...
I'm loaded with optimism!! Bring on December! If that don't work, bring on January! If that don't get it done, fab February will bring the funk! :)
 
Webberweather53 said:
In all likelihood February will be "funking" ugly so we most likely have just December and January to get it done
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That's what has me concerned. If the mid-December pants bursting pattern being shown on the weeklies and EPS, gets pushed back two weeks, like it inevitably does from winter to winter, then we are into January, chasing that strat-warming unicorn, again! :(
 
With all of the forecasts for a more front-loaded winter, it would be just like mother nature to distribute a 1993 redux LOL
 
Per 12Z ensemble consensus: looks rather torchy in the SE the 1st week of Dec (and perhaps a bit more torchy than the 0Z) thanks to our friend, the SE ridge. However, the sharp turn to colder soon afterward is still there and, if anything, looks colder than the 0Z consensus with a very nice -AO/-NAO/+PNA combo. This colder change would be following the QBO/ENSO/Nov AO/MJO analogs very well. Before the several early Dec torchy days, the rest of Nov should average near normal (cool followed by mild).

Note that no more than the first week of Dec is looking mild. Compare that to how early Nov was looking on the models at this point in Oct: similar to now there was then a turn to a torch after a chilly late Oct with no end in sight to that early Nov torch. Worries about an overall warm Nov were heard throughout wx land from amateurs and even a number of pros. But then we started seeing the models cool with just about each and every run for the period starting 11/8, which eventually resulted in a considerably colder 2nd week of Nov than earlier thought thus bringing a cautious smile to wx fanatics. For Dec, we don't even need to worry about a warm 2nd week+! I remain pumped.
 
GaWx said:
Per 12Z ensemble consensus: looks rather torchy in the SE the 1st week of Dec (and perhaps a bit more torchy than the 0Z) thanks to our friend, the SE ridge. However, the sharp turn to colder soon afterward is still there and, if anything, looks colder than the 0Z consensus with a very nice -AO/-NAO/+PNA combo. This colder change would be following the QBO/ENSO/Nov AO/MJO analogs very well. Before the several early Dec torchy days, the rest of Nov should average near normal (cool followed by mild).

Note that no more than the first week of Dec is looking mild. Compare that to how early Nov was looking on the models at this point in Oct: similar to now there was then a turn to a torch after a chilly late Oct with no end in sight to that early Nov torch. Worries about an overall warm Nov were heard throughout wx land from amateurs and even a number of pros. But then we started seeing the models cool with just about each and every run for the period starting 11/8, which eventually resulted in a considerably colder 2nd week of Nov than earlier thought thus bringing a cautious smile to wx fanatics. For Dec, we don't even need to worry about a warm 2nd week+! I remain pumped.
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Yeah the EPS suite starts to look good by 324 hours, if we can hold this look through the end of the upcoming week & get some support w/ an MJO pulse or CCKW, definitely will be a very legit pattern change.
eps_z500a_noram_55.png
eps_t850a_noram_61.png
 
if we get the nao ao negative thats fine... but positive pna going to lead to a suppressed pattern nothing but cold dry... meh i take my chance with the pna slightly negative to nuetral....
 
tennessee storm said:
if we get the nao ao negative thats fine... but positive pna going to lead to a suppressed pattern nothing but cold dry... meh i take my chance with the pna slightly negative to nuetral....
Click to expand...

A neutral or negative PNA will result in the forthcoming pattern the first week of December which is blowtorch warm with absolutely no chance whatsoever for wintry weather... A +PNA doesn't automatically mean the pattern is "suppressed & dry". In fact a +PNA in NDJ, reminiscent to an El Nino (as one would expect given ENSO is moderately correlated w/ the sign of the PNA) actually favors a colder and stormier pattern in the southeastern US, especially for Texas, North Carolina, South Carolina, Georgia, and Florida... The Tennessee Valley of course tends to lose out during a +PNA (as it also does during an El Nino), but when coupled w/ a NINA base state, it likely won't be as dry as would be observed if the +PNA/-NAO was coupled w/ a NINO...

NOAA US PSD Climate Division precipitation correlation w/ +PNA in NDJ
climdivcorr.2606-a000-1500-8005-898b-ae9-3104-a5d.327.16.53.26.prcp.gif
 
It is worth mentioning here that while the pattern the next week or two is not terribly conducive whatsoever to wintry weather in the southeastern US, this pattern could be helping us in the long run. Although having a big vortex over northeastern Eurasia (+WPO) is favorable for mild Pacific air to flood North America, this trough is actually increasing the Wave Activity Flux (WAFz) onto the stratospheric polar vortex that's associated with upward propagating planetary waves from the troposphere. As these waves constructively interfere with the mean wave pattern, they more effectively decelerate the westerly polar night jet encapsulating the polar vortex, which due to thermal wind relation, warms the polar stratosphere and if these anomalies propagate into the troposphere, they can significantly alter the tropospheric AO/NAO...

Here's a crude picture of the mid-upper level planetary wave configuration in the Northern Hemisphere
Northern Hemisphere Mid-upper level Planetary Wave Configuration.png

Given how similar the pattern over the next week or so on the guidance is to the mean planetary wave configuration shown above, it's not surprising that it ends up being pretty similar to the Garfinkel et al (2012) sudden stratospheric warming event precursor...

gfs-ens_z500a_nhem_26.png
Screen Shot 2017-11-24 at 7.41.05 PM.png
 

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tennessee storm said:
if we get the nao ao negative thats fine... but positive pna going to lead to a suppressed pattern nothing but cold dry... meh i take my chance with the pna slightly negative to nuetral....
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You want a strong positive PNA. A strong positive PNA favors a western ridge and a trough over the east. In the coming days, the ENS mean of the PNA is trending towards slightly above positive to neutral then back slightly negative. NAO is slightly negative and will continue to do so. The AO is trending towards neutral, then back to negative. The way the teleconnections are now, favor some quick shots at cold air over the east, but warmer than avg. will be more dominant vs colder then avg. The only area that has a better chance at winter precip. is the far northeastern US for now. Also, a positive PNA doesn't necessarily mean suppressed systems.
 
I'm ready for some weather in forecasting range... there's not even rain here til fantasy land

The 18z GFS didn't even have a freeze in Chicago the entire run, their average low next week is 26
 
SoutheastRidge said:
Thats just crazy that Dallas had 20" in one winter. You never EVER see Atlanta get that much snow, despite the fact that Atlanta gets on average about the same as Dallas.
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most of that fell in one storm on February 11, 2010, 12 inches of snow at the airport, totally unexpected lol

also there was up to 8 inches in the northern suburbs on the first day of spring after that! also unexpected
 
CHA has had 5 20+ seasonal snowfall totals since 1870. Most recent being 92-93 of course. The closest we've come since then is 10-11, with 12.6. A La Nina year too..
 
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10-11 is a pretty decent analog right now... and that year wasn't too bad here either. Had a week in February 2011 where snow/ice stayed on the ground(leading up to when Dallas hosted the Super Bowl), there were all kinds of problems even after temperatures had warmed up into the 50s by then

it was first a sleet storm on the heels of an arctic front and then several inches of snow a couple days later, the two days in between had temperatures barely in the 20s for highs

the winter otherwise was pretty torchy
 
The lack of precipitation in the continental US currently is pretty dramatic. Don't know how unusual that is. There's a patch of rain in NW Washington state and a few showers in Michigan. That's it.
 
whamby said:
The lack of precipitation in the continental US currently is pretty dramatic. Don't know how unusual that is. There's a patch of rain in NW Washington state and a few showers in Michigan. That's it.
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its really amazing how quiet the weather is literally everywhere

Calm before the storm? ;)
 
whamby said:
The lack of precipitation in the continental US currently is pretty dramatic. Don't know how unusual that is. There's a patch of rain in NW Washington state and a few showers in Michigan. That's it.
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Seems rather unusual for late November.
 
GFS continues to look great at 384!
:(
 
cd2play said:
Is the mid-December cold still on the table?
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Yes, this is from the GEFS, this is the look you need to have cold in the east. This look favors below normal temps. over the east. If this look holds, we should start to see a
+ PNA, - AO. There would probably be a
- NAO as well with the Greenland blocking.

I'd think the east will experience below normal temps. with higher chance at winter precip. including the SE. Especially the upper south by mid December.
de9f0b0ae1dd01790f6914b564b10d62.jpg


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Storm5 said:
Yeah the 12z GEFS post 300 is belt bursting exciting
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Isn't it always?? :(
Let's see some pants busting inside 200 hours for a change!
 
Storm5 said:
Belt bursting
82e2fd12b5035d71e3c588d1fff81948.jpg


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I get it! Let's see if it remotely looks like this on Dec 9th! Pants busting or pants deflating?? Time will tell
 
The GFS could be onto something. 6z had winter mischief mostly over the upper south and the 12z GFS also had winter mischief. Both runs had it over the 300 hour mark. The reason why I say the GFS could be onto something is because it showed winter mischief twice past 300 hours. What's the chance? Still a small chance of anything happening, but if we start to see consistency, the chances of something wintry happening goes up.

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The models can only "say" so much. Truly enjoying the interpretations and translations. Nothing of value to add, except ... Thanks!
Best,
Phil
 
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