Thursday, October 27, 2016

Thursday Morning Note

Current radar shows a decent idea of precipitation type as it matches many of the observations I have been looking at..



Snow to the north some light freezing rain to the south where you see the pink. 


Next week we get a very nice warm up. Temps can reach the 70's in spots!


However, as I have been talking about all signs point to a very cold November from the 2nd week of November on. The models are still supporting this. Due to that unprecedented split in the polar vortex, we will see how this really plays out (a weakening polar vortex is a major wild card). Will November be more like December? We will have to wait a little longer to see.

By around the 6-10th the models really start to show a massive ridge crank along the west coast..



How quickly this evolves is up for debate as some models are slower than others. They all eventually show this..



I am very confident in the high latitude blocking to support this pattern. At this time the only thing that would flip this is if the pacific jet g0t too strong and it overpowered the pattern. That can happen but that is not my forecast at this time.

More in days to come. 

8 comments:

  1. Hey Willy, interesting stuff, patterns are changing, winter is starting to set up. I see that you use that tropicaltidbits site -- definitely a good resource, I have their model page bookmarked. I love that time slider that allows you to view the model scenarios unfolding like a video. I did that for some of the ensemble and synoptic models for 500 mb heights, and even though we definitely have some troughs heading our way here in NJ, the national 2-week pattern still looks fairly progressive to me, FWIW. Kind of like waves flowing across a body of water. Ridge then trough then ridge then trough. But of course, 384 hour model scenarios often turn out to be science fiction. I see that the AO and NAO 14-day forecasts are quite negative, but PDO stays +. As of this AM, polar temps on the ground and in the stratosphere have generally been trending below normal (despite the low sea ice levels), but no sign yet of any spike. There will certainly be jinks up and down, but it remains to be seen when the first noticeable spike happens and thus the AO really gets rattled. So, FWIW, I clearly agree that November is not looking anything like last year, when Nino kept things balmy and cherry trees were blooming on New Years Day. But as to whether it's gonna be different in the other direction from a normal November and early December, the jury still seems to be out IMHO. Accuweather long-term forecasts don't win prizes for their skill levels, but FWIW, they see mostly normal seasonal temps thru early December. The other interesting question of course is when the dry spell in the east breaks. Accu/w sees a dry November but maybe normal precip in December (which could get interesting and messy). Again, FWIW. Jim G

    ReplyDelete
    Replies
    1. As usual, I need to offer a correction -- according to the Danish Meteorological Institute web site, polar region ground temps have stayed above average since late summer; there's the low sea ice effect, less sunlight reflectance. They also took a jink upward over the past few days, albeit nothing too unusual. But with above-avg temps in the tropo and below-avg temps in the strat, perhaps the potential for energy flux between the layers is building up. Which can help trigger SSW's, if I understand correctly (and inadequately). Will be monitoring. Jim G

      Delete
    2. Yeah, tropicaltidbits.com is a great site for a quick glance at the weather models. Its very user friendly. I usually use wxbell and accuweather pro for the in depth analysis but to keep things simple on the blog tropicaltidbits does the trick. The tricky thing with ensembles is the blends of all the different members in the long range dilutes what the actual pattern will look like. Many times a zonal flow can in reality be a ridge trough relationship; especially if you have a high spread of where the members are placing the pacific jet. The key here is I think the AO projected to dip down again will not support a zonal flow by day 10+. From my expereience, you need to use analogs with the models to see if you get the agreement on where you think pattern will "go".

      As far as the strat is concerned, models are really jumping on those temps spiking in next two weeks from 50 to 10mb. Check out the recent heat flux from the JMA website http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/gif/zuep_nh.gif that will help support this. In fact, they have not backed down on a wave 2 pattern or in other words a split into two seperate lobes. This will have big impacts on the AO for 2nd half of November. The jury is still out of course, but we got a lot of data (including last nights euro weeklies) to support this.

      Will it snow in our backyards? Still will be hard for anything substantial as November climatology does not help, but our first coating to maybe a few inches is def in the cards. Up in ski country I really think they get off to an early start this November.

      Its funny, some winters it wants to snow some winters it just doesn't. Mother nature always has her way. I think we will find out real soon what 2017 will have in store. I am getting excited here bc we are starting to see this active storm track set its self up in New England. As the season matures this will shift south and get the mid atlantic in the mix. OF course I can be 100% wrong about all of this but at this time I like what I see. Lets see what curve balls Mother Nature throws at me.

      Delete
    3. Jim also check this out (EMCWF 96 hr forecast of zonal winds). http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_u_f96.gif Notice the shift in zonal winds between west (orange colors) to east (blue colors) from 70 to 90N at 50 to 10mb. That would be extremly impressive for the strat. Shows the vortex under stress.

      Delete
  2. Yea, OK Willy, thanks mucho, most interesting. So the models see anti-cyclonic polar winds by the end of the month between 10 and 100mb, get the stratospheric shorts and T-shirts out, SSW time. But what's that mysterious QBO been doing down in the tropics (or up in the tropical stratosphere, however you want to look at it)? Is it still westerly, or did it get back to normal? If still westerly, it might mitigate the polar SSW's and negative NAO, or so I've read. This is cutting edge stuff AFAIC. Jim G

    ReplyDelete
    Replies
    1. Yup that's correct, you can see the qbo on that wind chart and it's westerly..that can Def fight against the pattern but the qbo might be fighting a loosing battle..we will learn alot about how much of a driver it really is. If this pattern doesn't flip to cold I think that qbo will really make a name for itself as more of a driver than an enhanced of a pattern

      Delete
    2. For those of you at home (like me) who want to follow this stratosphere wind and temp stuff, here's the Freie University site where these zonal wind maps and other good stuff is available:
      http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html
      OK, so by Nov 1, the ECMWF analysis (i.e., the gold-standard "Euro Model") shows easterlies (winds blowing from east to west) over the Arctic (70 to 90 deg N) in the stratosphere from 10 mb height all the way to the ground (blue zone is for easterlies). From my crude understanding, westerlies are the usual "cyclonic" flow as they follows the rotation direction of the earth. When you go against the usual flow, you can mix things up, like stirring your coffee with a spoon. So the warm air energy in the tropo can then "flux" its way up to the very cold stratosphere, and the sudden warming of the stratosphere then puts downward pressure on the polar vortex wind currents in the troposphere. That pressure can drive the vortex south and make it wobble and do funny stuff, maybe even splitting into two loops temporarily. The wobble and funny stuff thus pulls chilly Arctic air down over the Great Lakes and into the continental USA, and our thermometers plummet, probably in Europe too.

      OK, but the charts say that by Nov 7, the easterlies seem to be coming back in the Arctic stratosphere, at least above 30mb. So we shall see how big an SSW jump we get from all this. And yea, I think I can see the westerly QBO, that little curl of orange tones (orange is for westerlies) between 10 and 50mb from the Equator up to 10N. This area seems to be a fixed feature in all of the daily zonal wind runs thru Nov. 7.

      I don't understand how a westerly QBO down in the tropics promotes a stronger polar vortex (one less prone to wobble and split), but I don't feel too bad about that, cause here's a quote from an academic article on just that subject: "The stratospheric polar vortex is weaker in the easterly phase of the quasi-biennial oscillation (QBO-E) than in the westerly phase (QBO-W), but the mechanism behind the QBO's influence is not well understood." So yea Willy, the whole QBO thing is way up in the air (literally and figuratively!); maybe it's just some kind of ENSO and MJO hang-over, maybe it's an independent "driver" factor. Agreed, maybe the weather PhD's will get some more QBO clues from this season! And also we interested observers. Jim G

      Delete
    3. Correction, as usual -- need better proofreading skills! -- BY NOV 7, THE WESTERLIES SEEM TO BE COMING BACK . . . cyclonic WESTERLIES, not anti-cyclonic EASTERLIES.

      Delete