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Winter Speculation 17/18 -December Thread


AMZ8990

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2 hours ago, weathertree4u said:

Sounds good. I am real close to pulling the spring lever! Good too see the rain for sure. Dismayed that seems like we all lament the models each year how they are struggling with what ever pattern is present. Is this a ongoing thing? Seems like each year it is the same. Cannot even imagine what it must have been like to forecast the weather when I was a kid, back in the 70's, perhaps was easier back then!

Yeah...just organized the fly tying table.  We will see if the Davis Straits deal holds.  Definitely have been hints, but usually not on both models.  This SSW may be changing the pattern...we will see.  Reshuffle may be on tap...and reshuffles may be good or bad, but if the original deck was bad...a reshuffle is our best shot.

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This is the 12z GEFS 500 and 2m temp map for days 11-15...This is why I am not giving up on winter yet.  Look at the Davis Straits.  A lot of moderation there and if one looks at the daily maps, it looks as if the pattern over Greenland has flipped if the last couple of days of the ensemble are to be believed.  That is something to watch anyway.  The 0z EPS was very close to the same look.  It might be just enough to make the last half of February a bit more interesting.  I also added the Euro MJO plot which has now clearly corrected to phase 8 and looks as if it may correct to a higher amplitude.  

5a7747a12519c_ScreenShot2018-02-04at12_42_26PM.png.de6cf7ddcdc7ef2fa7323faff5936c66.png

5a77483663e51_ScreenShot2018-02-04at12_43_16PM.png.61266d98f8a7b74beafb28d100ed0c0e.png

5a77483e90bf8_ScreenShot2018-02-04at12_48_03PM.png.03775879b9fa9dca76c274f8e1019f91.png

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I'll throw these out there too. I found them in a CPC Powerpoint.  Somehow I can never remember exactly which phase correlates to what in our area. Lots of recent talk about MJO, so I poked around a bit to try and find these images for reference. These are the temperature and precipitation anomalies for each phase and corresponding "measure of significance for the anomalies. Purple shades indicate anomalies which are at the 95% or better confidence level". That's in quotes because I want to be accurate with what I'm showing, but am not entirely sure what that means statistically.  (I'm a historian who likes snow and thunderstorms, not a statistician).  Also not sure how long a lag time there is for a specific phase to be reflected in a particular anomaly.

Source for images: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf 

 

Also @Carvers Gap That orange PV/ SSW clip is awesome! It's mesmerizing, akin to watching a lava lamp for me anyway. 

MJO temp phases.png

MJO precip phases.png

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Jeff has noted that higher than normal global winds change the outcomes depicted on the MJO correlation.  Will be interesting to watch.  Plenty of cards being played right now w MJO rotation into normally favored phases w the global wind impact on results being duely noted, the predicted SSW, the Davis Straits showing some evolution to normal or AN heights, the -EPO ridge which teleconnects to an eastern trough, Nina climotology which argues for a decent SER.  Challenging but interesting weather on tap I believe.

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1 hour ago, Carvers Gap said:

Jeff has noted that higher than normal global winds change the outcomes depicted on the MJO correlation.  Will be interesting to watch.  Plenty of cards being played right now w MJO rotation into normally favored phases w the global wind impact on results being duely noted, the predicted SSW, the Davis Straits showing some evolution to normal or AN heights, the -EPO ridge which teleconnects to an eastern trough, Nina climotology which argues for a decent SER.  Challenging but interesting weather on tap I believe.

All well and good but eventually shouldn't we see it in the modeling?

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38 minutes ago, weathertree4u said:

All well and good but eventually shouldn't we see it in the modeling?

The real question is, "What should we be seeing in the modeling?"  Maybe we are seeing it in modeling, maybe not.  With a forecasted total split of the PV, an MJO headed into phase 8, a steadily falling -QBO, the global wind situation that Jeff mentioned, blocking signals...BTW the 12z EPS holds w a -NAO at d14 and moving forward in time, I think the Ventrice tweet above pretty much sums it up.  

The EPS 12z control shows a deepening eastern trough late in its run which would result in an Arctic outbreak.  The mean has the same thing but is washed out by warmer solutions and is warm.  The GEFS has a colder pattern, but is similar at 500 to the EPS.  But w so many variables, I suspect modeling is about to jump all over the place.  

To me the medium and LR are now a total crapshoot.  With so many variables in play, I wonder if we are about to see some wild swings in modeling during a winter that has already had many.  If the models showed wall-to-wall cold with those multiple items in play, would I believe the solution?  No.  Same goes with the current solutions.  Right now, the models are juggling a dozen plates.  But that is what makes this hobby interesting.  Just like trying to guess the picture on a puzzle in which you get more pieces as you get closer to finishing it.

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2 minutes ago, weathertree4u said:

There certainly was some cold showing on the CFS latest run but not sure how reliable that is but it is a change.

Yeah, I can generally pick one run of the CFS runs that shows what I want during a given day.  LOL.   But....if that -NAO is legit, we will see. I honestly don't know how global models will handle the SSW once it happens.  They have modeled the split pretty well which is amazing that we have wx models that can model a SSW.  But what happens in the troposphere after that is anyone's guess.  I suspect the after effects of the SSW will be like a bull in a china shop.  It is my understanding that there is a decent amount of correlation between an SSW and high latitude blocking because of all of the heat over the pole at multiple levels of the atmosphere.  I am pretty excited, because this might be a reshuffle to what looked like a pretty bad hand.  Now the reshuffle might be bad....but at least you get another shot at it.  I mean one would think that a -EPO, -QBO, potential -NAO, SSW, MJO phases 8/1/2 and dropping SOI would have some positive impacts on the EC...or at the very least cancel out some bad signals such as the global wind and waffling AO.  The EPS control for the second run in a row depicts a big trough in the East where the mean is washed out and in Canada.  

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18 minutes ago, weathertree4u said:

There certainly was some cold showing on the CFS latest run but not sure how reliable that is but it is a change.

Interesting tweet...I translate this to mean AN heights over high latitudes.  You can actually see a raging -NAO during the last two runs of the GEFS.  Now, the NAO is not a magic bullet I should add.  There have been times that we have had one and been toasty.  However, it definitely helps with slowing down storms and allowing a phase.  But overall, it is the second best driver of our weather IMO outside of a great Pacific set-up.  I truly don't think we will know the consequences of the SSW until it actually happens and the models can see if/how it translates to the troposphere. 

 

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Weeklies are warm as expected....but interestingly a new feature has appeared.   Like in the movie Hoosiers, right about the time Norman Dale is about to be fired...in walks Jimmy Chitwood.  In this case it is a raging -NAO which is likely a result of the SSW.  "-NAO leaves, winter leaves.  -NAO stays, winter stays."  Or something like that....there you go, Jeff. Basketball and weather.

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To say the control NAO is negative does not do it justice on the control.  Whoa!  IMHO, the Weeklies are just now sensing the SSW as evidenced by  the NAO going negative.  That or the QBO is doing its work.   The 2m temps are warm but I can live w the 500 pattern.  The PV is forecast to split Feb 10-12.  Add about a week for troposphere impacts.

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8 minutes ago, Carvers Gap said:

And if the Euro is playing catchup on that key pieces, who is to say it is not on the rest of the forecast.  Very interested to see if its operational holds to the look it had late in its run this morning.  

Interesting times; enjoy everyone's posts, so informative. Essentially, we could be seeing a change in the long range over the next couple of days?

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42 minutes ago, weathertree4u said:

Interesting times; enjoy everyone's posts, so informative. Essentially, we could be seeing a change in the long range over the next couple of days?

No way to know.  This SSW is a major shake-up.  If the -NAO materializes, I have to think the SE sees some slowing of storm tracks and cold...but there are examples in years past where it is warm.  Plenty of signals argue for cold, even if the lion's share goes to Russia.  Canada cold will do the trick even if we don't have Arctic cold.  Right now the models are warm...but obviously I am suspect of that look.  We will know soon enough.  Looking forward to the opening ceremonies of the Olympics on Friday...at least I can see snow on TV!

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