February Medium/Long Range Disco Thread 2

[BTRWx]

1 hour ago, dallen7908 said:

Certainly an exciting week first week of March coming up for residents of Madison  ... or Ottawa .. or .... 

Looks like one storm after another perhaps one will track far enough south to give us mixed precipitation. 

 

A couple of poster's have noted that storms need less spacing in the spring than they do in the winter - something about shorter wave lengths etc. Could someone explain 

I hope I can screenshot this figure without issues from the author. http://onlinelibrary.wiley.com/doi/10.1256/qj.02.200/pdf

 

 

[Scraff]

A mod can delete if we are in storm mode, but ain't (yes I know proper English) this song straight up truth!?  I've officially lost it...though did I ever have it? Probably not...

#NotMyWinter

[osfan24]

Probably time to shut this down and create the March long range thread.

[mdsnowlover]

Classic NPO flip. 5-day normalized slp anomalies on 18z GEFS into early March. can someone explain , this from anthony maiesllo

 

 

 

 

 

 

 

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[psuhoffman]

13 hours ago, mitchnick said:

The waffling of the Euro weeklies this winter has been comical.  The Gefs have been far too optimistic regarding cold as well. The Canadian suite of the Cansips and Geps have remained fairly consistently warm and the Geps have not been giving false signals/hope of troughing in the east. Canadians win this winter hands down in my book....ok, everything other than the ggem and rgem. Lol

 

19 hours ago, mitchnick said:

Canadian GEPS says GEFS on crack and keeps the eastern ridge through the end of its 12Z run (384 hrs.) Nice test between it and GEFS.

That battle ended quickly. Geps is now identical to gefs day 15-16. They compromised on a middle solution. Both imply the cold boundary pushed in the east the second week of march. A bit more southeast ridge then I like that late but the cold is pressing and all 3 EPS gefs and geps have the better North Atlantic look.  Probably just the guidance trolling us one last time. 

[mitchnick]

24 minutes ago, psuhoffman said:

 

That battle ended quickly. Geps is now identical to gefs day 15-16. They compromised on a middle solution. Both imply the cold boundary pushed in the east the second week of march. A bit more southeast ridge then I like that late but the cold is pressing and all 3 EPS gefs and geps have the better North Atlantic look.  Probably just the guidance trolling us one last time. 

To be fair, the 500mb anomaly map from 384 hrs. off the 0Z is below. I don't know about you, but for a 7PM March 8th prog, that's not going to do us any good when it comes to snow.

 

Nonetheless, I hope you're not suggesting that simply because the GEPS gives us -2.5 - .3C 850 anomalies on its 384 hr. map for 3/8, it hasn't been consistent with its warm and (ultimately) correct look all season. Otoh, Euro weeklies have been a joke along with the GEFS as they have been vacillating between warm and cold runs. 

[psuhoffman]

13 minutes ago, mitchnick said:

To be fair, the 500mb anomaly map from 384 hrs. off the 0Z is below. I don't know about you, but for a 7PM March 8th prog, that's not going to do us any good when it comes to snow.

 

Nonetheless, I hope you're not suggesting that simply because the GEPS gives us -2.5 - .3C 850 anomalies on its 384 hr. map for 3/8, it hasn't been consistent with its warm and (ultimately) correct look all season. Otoh, Euro weeklies have been a joke along with the GEFS as they have been vacillating between warm and cold runs. 

Both valid points and I don't disagree with the general premise of either but let me be contrarian (stay in character) and offer an alternative narrative.  Your first point is correct in that it is far from a perfect setup, but its also not as bad as simply looking at the local H5 heights would imply.  Not all H5 heights at equal.  That look with the blocking up top and some pretty serious cold locked in under it in Canada would mean the cold is pressing, and will encroach into the ridge more then in some similar h5 height patterns.  Also were talking about a washed out mean, but if a specific vort can dig within that pattern its very possible it gets under us.  Especially if its coming on the heels of another wave in front.  I could see something rotating up to our northeast and then a second vort coming around behind it under us and taking advantage of the shorter wavelengths in March to pop something decent, and in that case the bit of ridging to our south could prevent suppression.  I can envision a way it works.  I can also see how it fails because it is less then perfect.  And as for the 850 temps, even mid march mean 850 temps are still pretty cold so that is one reason I use that instead of surface.  Also surface is the least accurate of all the long range plots, and surface in March can be biased by some warm dry days when if there is a storm it won't be that warm.  Those 850s there are not great but close enough to imply there is a chance.  Have to keep in mind there are probably members within the ensemble that are warmer and say NO snow.  But there are also members within that are colder then that.  And there are timing differences at that range between warmer and colder days being washed out.  So again, is it an OMG its gonna snow pattern no, but could I see it snowing in that pattern, yea.  

As for the GEPS, have they been on the level warmer all winter yes.  Has that made them right in that one factor in our specific location yes.  But I was looking at verification of the guidance a few weeks ago and the GEPS was way below the EPS and GEFS.  Now those h5 verifications are hemispheric so of course the GEPS could be doing better RIGHT HERE while failing miserably overall.  But it does matter as weather is not all micro.  Also, we did have colder periods back in December and early January and in both the GEPS was the last to the party, and it completely missed the cold week early in January until well after the GEFS and EPS caught on.  Then in later January the GEPS did jump on board for a colder early Feb look for a couple days before it too bailed so it was equally wrong.  It also was the last to catch the -NAO we just had that lead to the very snowy period in New England.  If you were living in Boston you would probably be saying the GEPS has been awful and too warm lately.  I usually don't give credit when a model is correct with ground truth for a specific location but for the wrong reasons.  

That said I was being nitpicky and your overall points are sound, the pattern is flawed and less then ideal and the GEPS was warm most of the winter and we were warm most of the winter.  

[psuhoffman]

2 hours ago, osfan24 said:

Probably time to shut this down and create the March long range thread.

Should I do the honors?  Haven't tried one of these in a while so maybe it flips our luck.  If not, oh well, nothing to lose.  

[PCT_ATC]

8 minutes ago, psuhoffman said:

Should I do the honors?  Haven't tried one of these in a while so maybe it flips our luck.  If not, oh well, nothing to lose.  

Please do!

[WinterWxLuvr]

36 minutes ago, psuhoffman said:

Both valid points and I don't disagree with the general premise of either but let me be contrarian (stay in character) and offer an alternative narrative.  Your first point is correct in that it is far from a perfect setup, but its also not as bad as simply looking at the local H5 heights would imply.  Not all H5 heights at equal.  That look with the blocking up top and some pretty serious cold locked in under it in Canada would mean the cold is pressing, and will encroach into the ridge more then in some similar h5 height patterns.  Also were talking about a washed out mean, but if a specific vort can dig within that pattern its very possible it gets under us.  Especially if its coming on the heels of another wave in front.  I could see something rotating up to our northeast and then a second vort coming around behind it under us and taking advantage of the shorter wavelengths in March to pop something decent, and in that case the bit of ridging to our south could prevent suppression.  I can envision a way it works.  I can also see how it fails because it is less then perfect.  And as for the 850 temps, even mid march mean 850 temps are still pretty cold so that is one reason I use that instead of surface.  Also surface is the least accurate of all the long range plots, and surface in March can be biased by some warm dry days when if there is a storm it won't be that warm.  Those 850s there are not great but close enough to imply there is a chance.  Have to keep in mind there are probably members within the ensemble that are warmer and say NO snow.  But there are also members within that are colder then that.  And there are timing differences at that range between warmer and colder days being washed out.  So again, is it an OMG its gonna snow pattern no, but could I see it snowing in that pattern, yea.  

As for the GEPS, have they been on the level warmer all winter yes.  Has that made them right in that one factor in our specific location yes.  But I was looking at verification of the guidance a few weeks ago and the GEPS was way below the EPS and GEFS.  Now those h5 verifications are hemispheric so of course the GEPS could be doing better RIGHT HERE while failing miserably overall.  But it does matter as weather is not all micro.  Also, we did have colder periods back in December and early January and in both the GEPS was the last to the party, and it completely missed the cold week early in January until well after the GEFS and EPS caught on.  Then in later January the GEPS did jump on board for a colder early Feb look for a couple days before it too bailed so it was equally wrong.  It also was the last to catch the -NAO we just had that lead to the very snowy period in New England.  If you were living in Boston you would probably be saying the GEPS has been awful and too warm lately.  I usually don't give credit when a model is correct with ground truth for a specific location but for the wrong reasons.  

That said I was being nitpicky and your overall points are sound, the pattern is flawed and less then ideal and the GEPS was warm most of the winter and we were warm most of the winter.  

One of the best things I've seen posted all winter.  Anomaly maps are posted all the time, but many times those anomalies are only a few meters (50-100) but the map colors make it look like a torch or a deep freeze when the reality is that it is neither.  We don't necessarily need below avg heights to get cold and snow, especially in the heart of winter.