Jump to content
  • Member Statistics

    17,588
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Thanksgiving Eve Coastal


Coach McGuirk

Recommended Posts

  • Replies 1.4k
  • Created
  • Last Reply

To make matters worse soon we won't even have the old gfs to compare it to. So if it is indeed wrong and this were January it would actually be making the forecast confidence worse right now. Some "upgrade". Of course if it's right then...

Good grief.  The new system was run for over two simulated years and is demonstrably better than the current operational GFS.  Here is a large sample covering 2013: 

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhs13/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

and a large sample covering 2014:

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhw14/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

 

While only 500 mb AC, this is representative of many metrics.  While it may end up crapping the bed on this event (still TBD), the new system is better than the current operational GFS.  No upgrade is perfect.

 

For what it's worth, I have no vested interest as I no longer work for NWS and had nothing to do with this upgrade.

Link to comment
Share on other sites

Good grief.  The new system was run for over two simulated years and is demonstrably better than the current operational GFS.  Here is a large sample covering 2013: 

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhs13/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

and a large sample covering 2014:

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhw14/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

 

While only 500 mb AC, this is representative of many metrics.  While it may end up crapping the bed on this event (still TBD), the new system is better than the current operational GFS.  No upgrade is perfect.

 

For what it's worth, I have no vested interest as I no longer work for NWS and had nothing to do with this upgrade.

Thinking about it, with about 10 runs left before first precip, the para GFS would eventually brush the coast with the few miles west with each run.  Even with a 15 mile shift or so, that's 150 miles more inland.

Link to comment
Share on other sites

Good grief.  The new system was run for over two simulated years and is demonstrably better than the current operational GFS.  Here is a large sample covering 2013: 

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhs13/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

and a large sample covering 2014:

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhw14/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

 

While only 500 mb AC, this is representative of many metrics.  While it may end up crapping the bed on this event (still TBD), the new system is better than the current operational GFS.  No upgrade is perfect.

 

For what it's worth, I have no vested interest as I no longer work for NWS and had nothing to do with this upgrade.

 

 

I think that has always been the problem with the GFS and our mission here...We use it almost exclusively for east coast winter storms...and while it may be very good at many things as it is a sophisticated global model, east coast winter storms is not one of them...particularly coastals....looking forward to the upgrade though, and the improved results that will come with it...It may be right with this storm (though I doubt it).

 

Obligatory storm talk - I think things are looking good for a small, messy event for the city and bigger of course north and west,..getting specific with totals will be tough...

Link to comment
Share on other sites

It's close but verbatim, we're snow (rain to start?).  1000/850 thickness is 131 at onset and then 130 for the event, which supports a snow profile. Not much wiggle room.

 

i think briefly rain or white rain...though 36 and snow isn't that exciting....it will be a battle here at lower elevations...34 is the cutoff...I've never really seen a good pasting at 35...fortunately, if it is +SN, 33-34 seems reasonable and that would stick...I don't think anyone below 300' and east of 95 should get too excited...though any accumulating snow in November is cool....

Link to comment
Share on other sites

Good grief. The new system was run for over two simulated years and is demonstrably better than the current operational GFS. Here is a large sample covering 2013:

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhs13/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

and a large sample covering 2014:

http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/prhw14/allmodel/daily/dieoff/cordieoff_HGT_P500_G2NHX.png

While only 500 mb AC, this is representative of many metrics. While it may end up crapping the bed on this event (still TBD), the new system is better than the current operational GFS. No upgrade is perfect.

For what it's worth, I have no vested interest as I no longer work for NWS and had nothing to do with this upgrade.

I don't pick on the gfs as much as most as I find it very useful in many ways, however you can't deny it has a major issue resolving coastal systems. Weather due to feedback or not it struggles with the systems that are our big ticket items so it looks worse then it is I guess. Again I'm not talking about verification scores but specific details of a synoptic event. I will wait to see if the new gfs is better at resolving these coastal systems over time but if the old gfs/euro solution is right it's not off to a great start.
Link to comment
Share on other sites

I think that has always been the problem with the GFS and our mission here...We use it almost exclusively for east coast winter storms...and while it may be very good at many things as it is a sophisticated global model, east coast winter storms is not one of them...particularly coastals....looking forward to the upgrade though, and the improved results that will come with it...It may be right with this storm (though I doubt it).

 

Obligatory storm talk - I think things are looking good for a small, messy event for the city and bigger of course north and west,..getting specific with totals will be tough...

I'm always a little hesistant to jump with the new model on theblock even when it's been tested until I learn its biases.  My guess is that the parallel is too far east for this storm but that is no guarantee. I like that the UKEMT, GFS and Euro are in one grouping as I think outside of the parallel, they are the three best medium range models. 

Link to comment
Share on other sites

I think that has always been the problem with the GFS and our mission here...We use it almost exclusively for east coast winter storms...and while it may be very good at many things as it is a sophisticated global model, east coast winter storms is not one of them...particularly coastals....looking forward to the upgrade though, and the improved results that will come with it...It may be right with this storm (though I doubt it).

 

Obligatory storm talk - I think things are looking good for a small, messy event for the city and bigger of course north and west,..getting specific with totals will be tough...

Well, my expectation is that the new system *should* be better for Miller A systems where diabatic, nonlinear effects are critical.  THe new system has an increase in spatial resolution, improved (higher resolution) SST product used, and other physics-related changes....all of which should improve the predictions of this type of development.  However, the new package doesn't include a significant overhaul in the convective parameterization and I worry that the new Semi-Lagrangian dynamic core damps things a bit too much.  So perhaps my expectations are too high....

Link to comment
Share on other sites

Well, my expectation is that the new system *should* be better for Miller A systems where diabatic, nonlinear effects are critical. THe new system has an increase in spatial resolution, improved (higher resolution) SST product used, and other physics-related changes....all of which should improve the predictions of this type of development. However, the new package doesn't include a significant overhaul in the convective parameterization and I worry that the new Semi-Lagrangian dynamic core damps things a bit too much. So perhaps my expectations are too high....

The part about not upgrading the convective parameterization worries me that perhaps the same old issues with feedback will persist.
Link to comment
Share on other sites

I don't pick on the gfs as much as most as I find it very useful in many ways, however you can't deny it has a major issue resolving coastal systems. Weather due to feedback or not it struggles with the systems that are our big ticket items so it looks worse then it is I guess. Again I'm not talking about verification scores but specific details of a synoptic event. I will wait to see if the new gfs is better at resolving these coastal systems over time but if the old gfs/euro solution is right it's not off to a great start.

What do you mean by "weather due to feedback"?  Are you talking about the generation of diabatic heating through the convective scheme?  Is your comment meant to imply that this "feedback" is too strong or too weak?  How do you think this impacts coastal development?

 

I ask because the narrative is always that the "convective feedback" is too strong.  For a coastal, this would result in systems that are too wound up, since the convective scheme produces heating, which if you think about in terms of PV would enhance the development, etc....  Unless of course the feedback is strong *and* in the wrong location, which can result in the spin up of multiple vortices, etc.

Link to comment
Share on other sites

The part about not upgrading the convective parameterization worries me that perhaps the same old issues with feedback will persist.

No disagreement in principle in terms of the need to focus on developing/improving physics for the NCEP models.  I do have issues regarding the use of the phrase "convective feedback", however. 

Link to comment
Share on other sites

What do you mean by "weather due to feedback"? Are you talking about the generation of diabatic heating through the convective scheme? Is your comment meant to imply that this "feedback" is too strong or too weak? How do you think this impacts coastal development?

I ask because the narrative is always that the "convective feedback" is too strong. For a coastal, this would result in systems that are too wound up, since the convective scheme produces heating, which if you think about in terms of PV would enhance the development, etc.... Unless of course the feedback is strong *and* in the wrong location, which can result in the spin up of multiple vortices, etc.

without being able to get into the physics of why it seems to me just observing over the years that often times during the critical development period of a coastal storm the gfs will jump the slp off in the wrong direction and that throws everything after out of whack. On several occasions it seems it may have been feedback related where the gfs shifted towards an overdone region of convection. Again I don't have the ability to say for sure if that's the culprit it's just an observation I've had and sometimes those can be biased or misleading.
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...