Saturday, January 10, 2015

Upgrade of the GFS

I could continue to blog about our ongoing air quality problems, but thought some good news might brighten your day.

This Wednesday, beginning with the 1200 UTC run, the National Centers for Environmental Prediction (NCEP) will implement a major upgrade of the GFS Analysis and Forecast system.  Some of the major changes include:

  • Increasing horizontal resolution for the first segment of the forecast from what is effectively 27 km grid spacing to 13 km grid spacing and extending this first segment length from 192 to 240 hours.  This resolution increase puts the GFS on par with the NAM (~12 km) in terms of horizontal grid spacing.
  • Change from Eulerian to semi-Lagrangian dynamics.  OK, that's probably more than you want to know, but suffice to say that this is an improvement in the model dynamical core.  
  • Use of higher resolution sea-surface temperature analyses.  These analyses are ~5-km grid spacing.  I haven't had a chance to see what this means for the analysis of Great Salt Lake temperature.  If others out there have looked into this, please comment. 
  • Improved data assimilation.

For those of you who access GFS graphics on our site, right now I am not anticipating any problems, but just about anything is possible with a major upgrade like this, so don't hold your breath.  I will probably upgrade our data feed at some point to utilize higher resolution GFS output grids.  This includes access and use of "bufr" data for Alta (Yes!  They are finally adding this to the GFS product suite!).  How quickly I get to this is unclear and certainly dependent on weather, haha. 

Some of you have already been examining the new GFS forecasts as they have been running in experimental mode for some time.  Please comment on any significant changes in performance over the western U.S. that you may have noticed.

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