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Central PA - Winter 2020/2021 Part 2


MAG5035
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Red tagger just made this post in the thread to our south - this really resonates with me. I bolded what I've been saying for some time. I particularly like the last statement. 

 

During La Niña, models tend to over amplify weather systems several days out from onset. Overamped, too much moisture, only to see it correct toward the onset time. This latest event is a prime example as across the board guidance was giving a 6-10” area wide event and more like 10”+ on the euro, only to cave to a minor system...even by I-70 standards. Last storm very similar with the euro giving 25-30” at day 4/5 only to be cut back. For the hobbyist, it might be a sting to the gut, but for those working in the field, the inconsistency and wild swings have made forecast ops and communication to high level partners even up into high tier Gov partners a nightmare! Briefings for these “major” events that crop up at day 3-5 in NWP gain attention quickly then to have the rug pulled after you’ve messaged people is tough. One factor, could be minor, but it is a factor in such inconsistent data is the lack of domestic air travel in the U.S. we know the euro model in particular relies on aircraft data which air travel is 1/10th of what it was. Same with other guidance. Perhaps other factors we don’t know about. Niña years are tough as it is. Two conclusions I can draw from this season is... 1) the euro is not what the euro was, and 2) the NAM is useful outside its perceived “wheelhouse”. NAM is great at depicting changes, details in the pattern evolution that is not seen in the globals. It’s done well this season in that regard, overdone with front end waa snow.  3) it’s guidance only! Not verbatim. Know your patterns and climo vs model chasing. 

 

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Red tagger just made this post in the thread to our south - this really resonates with me. I bolded what I've been saying for some time. I particularly like the last statement. 
 
During La Niña, models tend to over amplify weather systems several days out from onset. Overamped, too much moisture, only to see it correct toward the onset time. This latest event is a prime example as across the board guidance was giving a 6-10” area wide event and more like 10”+ on the euro, only to cave to a minor system...even by I-70 standards. Last storm very similar with the euro giving 25-30” at day 4/5 only to be cut back. For the hobbyist, it might be a sting to the gut, but for those working in the field, the inconsistency and wild swings have made forecast ops and communication to high level partners even up into high tier Gov partners a nightmare! Briefings for these “major” events that crop up at day 3-5 in NWP gain attention quickly then to have the rug pulled after you’ve messaged people is tough. One factor, could be minor, but it is a factor in such inconsistent data is the lack of domestic air travel in the U.S. we know the euro model in particular relies on aircraft data which air travel is 1/10th of what it was. Same with other guidance. Perhaps other factors we don’t know about. Niña years are tough as it is. Two conclusions I can draw from this season is... 1) the euro is not what the euro was, and 2) the NAM is useful outside its perceived “wheelhouse”. NAM is great at depicting changes, details in the pattern evolution that is not seen in the globals. It’s done well this season in that regard, overdone with front end waa snow.  3) it’s guidance only! Not verbatim. Know your patterns and climo vs model chasing. 
 

I know you have been preaching climo for years on this board. It is one of the best predictors and IMO a more valuable tool than models.

Very much agree with everything said above.


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5 minutes ago, Itstrainingtime said:

Red tagger just made this post in the thread to our south - this really resonates with me. I bolded what I've been saying for some time. I particularly like the last statement. 

 

During La Niña, models tend to over amplify weather systems several days out from onset. Overamped, too much moisture, only to see it correct toward the onset time. This latest event is a prime example as across the board guidance was giving a 6-10” area wide event and more like 10”+ on the euro, only to cave to a minor system...even by I-70 standards. Last storm very similar with the euro giving 25-30” at day 4/5 only to be cut back. For the hobbyist, it might be a sting to the gut, but for those working in the field, the inconsistency and wild swings have made forecast ops and communication to high level partners even up into high tier Gov partners a nightmare! Briefings for these “major” events that crop up at day 3-5 in NWP gain attention quickly then to have the rug pulled after you’ve messaged people is tough. One factor, could be minor, but it is a factor in such inconsistent data is the lack of domestic air travel in the U.S. we know the euro model in particular relies on aircraft data which air travel is 1/10th of what it was. Same with other guidance. Perhaps other factors we don’t know about. Niña years are tough as it is. Two conclusions I can draw from this season is... 1) the euro is not what the euro was, and 2) the NAM is useful outside its perceived “wheelhouse”. NAM is great at depicting changes, details in the pattern evolution that is not seen in the globals. It’s done well this season in that regard, overdone with front end waa snow.  3) it’s guidance only! Not verbatim. Know your patterns and climo vs model chasing. 

 

I guess I’m just not good at reading the nam.  I use it  for temps and severe, but not much else. You guys are far better than me at this so maybe I should use it more. I will say I don’t model chase.  

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15 minutes ago, Itstrainingtime said:

I highly doubt next Tuesday's storm cuts. I'd bet money it goes underneath...question is, how far underneath...

You bring up a great point to be considered.  For that clue we have to look upstairs at 500s to see whats going on, and from my view, it comes at a time of relaxation so to speak.  If you look at said 500 panels, there's plenty of ridging to bring it up.  IMO we need that 1035hp to keep showing up to keep this thing cold enough w/ good CAD, or we could be in trouble.  Remember we are only knee deep in cold....not waist deep.  I think that HP showing up was the path to victory. 

JM $.02.

 

gfs_z500a_us_20.png
 

gfs_mslp_pcpn_frzn_us_19.png

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15 minutes ago, daxx said:

I guess I’m just not good at reading the nam.  I use it  for temps and severe, but not much else. You guys are far better than me at this so maybe I should use it more. I will say I don’t model chase.  

Not directed at you but I think big picture the constant "The Nam is out is wheel hour at 84 hours" type posts are just silly when every other models change drastically from run to run.  No model is within its wheelhouse at any point from the way they have performed recently especially with QPF totals.  The Nam has done a decent job at feature placement changes in the 84 hour time frame as opposed to the GFS.  All of this is indeed model chasing though.

 

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10 minutes ago, daxx said:

I guess I’m just not good at reading the nam.  I use it  for temps and severe, but not much else. You guys are far better than me at this so maybe I should use it more. I will say I don’t model chase.  

The NAM has some SERIOUS limitations. That's indisputable. One thing that I love about it is this - if guidance is showing a storm missing south and the NAM is further north and amped, a lot of times the rest of guidance will follow it. Not always, but my first "sign" to get excited is when the NAM is north of everything else. That's a double edged sword as well - there are times when the NAM is north of what we would want and other guidance nails us. We'll often fail while areas north of I 80 get smoked. 

It's wonky, it's jumpy, and yes, it can throw out absurd QPF amounts. It sounds like you use it similar to what I do - I just look for the positives that it can contribute, which there are some. 

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Just now, paweather said:

I have to be transparent with this sub forum and be honest and admit to the truth..........I am a model chaser. :D and I have been for over 30 years. 

I think this board would be dead without model discussion/chasing.  The science behind some of the more lengthy and complex posts concerning the not overly well understood (or accurate) forecasting of the NAO, AO, Nina's, etc. would not make for a high post count.  

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5 minutes ago, Bubbler86 said:

I think this board would be dead without model discussion/chasing.  The science behind some of the more lengthy and complex posts concerning the not overly well understood (or accurate) forecasting of the NAO, AO, Nina's, etc. would not make for a high post count.  

and to further that, there are always a myriad of ways that we can fail in any given event, whether its climo/telies/model tendencies....blah blah blah.....so yeah lengthy discussions on every model run aren't really warranted, till we get into close range.  Then we can nitpick finer details about winners and losers. :P.  In the last few years it seems like we really haven't locked much in outside of 72 which has to be beyond challenging for red taggers.  

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24 minutes ago, pasnownut said:

and to further that, there are always a myriad of ways that we can fail in any given event, whether its climo/telies/model tendencies....blah blah blah.....so yeah lengthy discussions on every model run aren't really warranted, till we get into close range.  Then we can nitpick finer details about winners and losers. :P.  In the last few years it seems like we really haven't locked much in outside of 72 which has to be beyond challenging for red taggers.  

which is what gets me with Jon Q public and bashing mets. like 2 storms ago when we had a mirage of weather, snow, sleet frzn etc and lasted for what, 3 days. How the hell can you forecast that shit? 

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That December storm was pretty well advertised in advance. Granted the jackpot moved north but the amounts the models showed did come to fruition.

Currently It almost seems like a perfect storm of items models have difficulty with (la Nina, progressive pattern with a unmoving block overhead) thrown in with a dearth of upper air aircraft observations


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