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OKpowdah

Analog approach to November and beyond

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Using October northern hemisphere 500mb heights, equatorial sea surface temperatures, and the QBO, and projecting the October 2013 pattern on all previous years, here are the "weights" I get for each year:

 

ftp://ftp.cdc.noaa.gov/Public/incoming/timeseries/octanalog9.txt

 

Check comparison of the October 2013 pattern to the analog mean pattern:

 

post-128-0-44175800-1383469534_thumb.gif

post-128-0-30685600-1383469567_thumb.gif

 

And then moving the analog means forward in time:

 

NOVEMBER

post-128-0-64371300-1383469848_thumb.gif

 

DECEMBER

post-128-0-09284100-1383469857_thumb.gif

 

JANUARY

post-128-0-60120800-1383469873_thumb.gif

 

Notice that the November pattern also aligns reasonably with what we are seeing unfold: the developing +NAO/-PNA pattern and ridging in the SE US.

 

Based on the analog composite, December is a warm pattern everywhere east of the Rockies. The January pattern has the potential to be cold and stormy for the Northeast US. The biggest signal is in that central to eastern Pacific trough, anchoring ridging over the western US. There's also disconnect in the AO and NAO. The continued west-based +NAO while coupled with above normal heights on the other side of the arctic can produce some shots of arctic air into the Northeast.

 

Just wanted to share a quit and dirty analog run. Happy switch back to standard time everyone!

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FWIW, 2006 is the strongest match. And what we're seeing in the EC ensembles long range and all, with a strong signal for continued warmth, matches pretty well with the 2006 November-December.

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You called that a quick analog, would take me months to figure out how to move analogs back and forward in time, nice work.

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FWIW, 2006 is the strongest match. And what we're seeing in the EC ensembles long range and all, with a strong signal for continued warmth, matches pretty well with the 2006 November-December.

Interestingly, January 2007 brought a significant pattern change to a much colder regime across a large portion of North America where temps and winter precipitation mostly in the form of ice, sleet and freezing rain developed very far S from AZ/NM/TX/OK/AR/MO and into LA stretching E and NE into Eastern Canada. I know we here in Houston had two fairly significant ice storms and 4 inches of freezing rain fell across portions OK into MO.

 

http://en.wikipedia.org/wiki/January_2007_North_American_ice_storm

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Interestingly, January 2007 brought a significant pattern change to a much colder regime across a large portion of North America where temps and winter precipitation mostly in the form of ice, sleet and freezing rain developed very far S from AZ/NM/TX/OK/AR/MO and into LA stretching E and NE into Eastern Canada. I know we here in Houston had two fairly significant ice storms and 4 inches of freezing rain fell across portions OK into MO.

 

http://en.wikipedia.org/wiki/January_2007_North_American_ice_storm

 

Yeah, I definitely thought of the second half of the 2006-7 winter also. I'm interested to see what direction ENSO slides toward, because with the QBO westerlies modulating the meridional overturning in the tropics, there's some support for a colder and stormier second half, a la late January- Feb-Apr 2007.

 

But I guess let's first see how well the analogs work through December :lol:

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Yeah, I definitely thought of the second half of the 2006-7 winter also. I'm interested to see what direction ENSO slides toward, because with the QBO westerlies modulating the meridional overturning in the tropics, there's some support for a colder and stormier second half, a la late January- Feb-Apr 2007.

 

Agree 100%. Would be nice to get a weakly positive ENSO to crank up the subtropical jet without overwhelming the polar jet...at least for us here in the Northeast :)

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Looking at 2006 specifically, end of January saw one of these...

 

http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2006_01_24.gif

 

If the AO annoys everyone enough over December then this will be light at the end of the tunnel if it were to repeat.

 

Thanks for the link to the ESRL PSD page, still learning the functions in there, can do daily datasets but not tried working that type of dataset before.  The daily ones have a lag of out to 20 days, whereas the monthly composite allows extended lag.over months. 

 

 

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So far, the analogs for November have nailed the major teleconnections: North Pacific ridging, lending to a -PNA, and +NAO --> east based -NAO, and the overall positive annular mode. However, the details in the longitudes of the three ridge axes have made a difference.

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FWIW, 2006 is the strongest match. And what we're seeing in the EC ensembles long range and all, with a strong signal for continued warmth, matches pretty well with the 2006 November-December.

 

This part hasn't worked out too well. There are different types of -PNA, and I would argue that the -PNA this month has not been typical. It's the big heights over the Aleutians that created it, but there has been little in the way of meaningful troughing over the West Coast, which typically happens downstream with a -PNA.

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While sensible weather in the US definitely didn't work out for the October analogs, the 500mb pattern features verified: Ridging over the north Pacific, lower heights across eastern Canada, ridging over the northeast Atlantic, ridging over western Asia -- overall mid latitude ridging and a positive index annular mode. 

 

post-128-0-83294700-1385916509_thumb.gif

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