[gradsusr] New meteogram with 0.25-degree GFS data

[Bonan Antonino]

This work on meteograms is very useful. We adapted the available script (retrieved from grads functions library) for our operational aims, since a long time, to get visual ideas about weather forecasts from models. We use ECMWF data.
So, just to get a better and fast visual forecast from thise kind of model output, we are left with (successful?) trials problems to solve.
Our plots of temperatures at 2 m not only contains the values at definite time steps (every 6 hours), together with dew point values... but also minimal and maximal temperatures of the (6-hourly) period ending at each step. The right visualization can let forecasters understand the plot without big efforts. We find that the shading by Jennifer is beautiful, but not so useful.
Plots of precipitation still have the problem of scaling, making different meteograms so difficult to compare...
The directions of wind in the upper plot can be badly understood by some forecasters, e.g. confusing between southerly and upward wind. Obviously, this is a problem with their hurry and not properly with the plots...
The upper plot has another more serious problem. Contour lines "come back in time" when (e.g.) an inversion layer is temporary. You can see that in the plot showed by Jennifer, let's say in the afternoon of 20JAN. As you can think, reality cannot be a freezing point which starts from the afternoon, lifts in the evening, go back to the same afternoon, get a time folding, then lowers in the same evening... It'just a graphical artifice, used by grads in its trial to plot a line being continuous in time/level surfaces. It is more difficult to avoid a wrong intepretation by forecasters, as they look for weather evolutions in meteograms: they could avoid the problem, only by looking for single snapshots... time step by time step. That is, they should abandon the comprehensive point of view of a meteogram!
I feel this problem could be faced with a new particular grads function: to get reliable plots in time/level surfaces, stopping contour lines when they "come back in time". I feel a script cannot be enough for such a purpose: at least, it would be too complicated.
Thank you for you work and good luck....

Dr. Antonino Claudio Bonan
Meteorologo
ARPAV- Servizio Meteorologico
via Marconi, 55
35037 Teolo (PD) - Italy
----- Original Message ----- 
  From: Jennifer Adams 
  To: GrADS Users Forum 
  Sent: Friday, January 16, 2015 11:09 PM
  Subject: [gradsusr] New meteogram with 0.25-degree GFS data


  Dear Users,
  I am working on transitioning my wxmaps.org scripts to use the 0.25-degree GFS output. The first script to test was the meteogram, below is a sample based on today’s 12Z forecast. I thought I would share it here and see if any of you want to give me some feedback while it is sitting on the top of my to-do list. I don’t modify these scripts all that often, so now is the time to express yourself, if you have an opinion. 


  The 3-hourly output goes out to hour 240, so now it’s a 10-day meteogram. That forced me to draw it in an 11x11 page to keep it readable. The image size will be bigger, too. The increased vertical resolution makes the top panel a bit crowded, even though I expanded its vertical real estate by merging the SLP and 1000-500mb thickness panels. I know the cloud cover variables are not of great interest, but please don’t vote to have them removed, I really like the way it appears that the bars in the precip panel are falling out of the clouds. For comparison, here is the link to the 0.5-degree meteogram: http://wxmaps.org/pix2/dcagfs.png. 


  If you are kind and helpful, I will package up the new script with a wrapper to get the needed data from our GDS to make it easier to draw a high-res meteogram for any location. 
  —Jennifer






  --
  Jennifer M. Adams
  Center for Ocean-Land-Atmosphere Studies (COLA)
  111 Research Hall, Mail Stop 2B3
  George Mason University
  4400 University Drive
  Fairfax, VA 22030 











------------------------------------------------------------------------------


  _______________________________________________
  gradsusr mailing list
  gradsusr at gradsusr.org
  http://gradsusr.org/mailman/listinfo/gradsusr
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20150121/95ac4651/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 846733 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20150121/95ac4651/attachment-0001.png