Major GFS upgrade (January 2015)

[Jeff Duda]

The GFS modeling system will undergo a significant upgrade starting on the 1200 UTC 7 January 2015 cycle. Some particularly important aspects of this upgrade as it may pertain to storm chasing and forecasting include

-Resolution improvement from ~27 km to ~13 km (similar to the NAM and RAP)
-Maintenance of the ~13 km resolution out to forecast hour 240 (with output available at 6 hrs from f192-f240) and improved resolution from ~84 km to ~35 km after f240
-Some fields will be output hourly between forecast hours 0 and 12
-Improvements to model physics, model dynamics, as well as initialization (additional obs being assimilated) and improved data assimilation system

What this means for the average joe:
GFS forecasts will be more accurate and products will be available more frequently at more distant lead times. It does not appear forecast latency will change.

See http://www.nws.noaa.gov/os/notification/tin14-46gfs_aaa.htm and links therein for more details.

 

[Skip Talbot]

Do the sites plotting GFS products like COD, TwisterData, and NCAR need to be retooled to handle these changes? In other words, do they need to redo their graphics processing to handle the higher resolution or to read in the grib data, or should we automatically see changes on these sites?

 

[Marcus Diaz]

That's good stuff. GFS seemed to do well in that mid range area. Now the resolution is even better. Should help finding trends in the mesoscale features.

 

[Jeff Duda]

Do the sites plotting GFS products like COD, TwisterData, and NCAR need to be retooled to handle these changes? In other words, do they need to redo their graphics processing to handle the higher resolution or to read in the grib data, or should we automatically see changes on these sites?

According to the notice, NCEP is changing some of the file names (and they're adding 0.25 degree output for all products; previously 0.5 degree was the finest they offered), so I presume anyone who makes graphics using GFS output is going to have to make adjustments to their scripts to get the new GFS data. Hopefully everyone who makes these graphics knows about the change and is prepared to handle them. I don't think sites will start failing to produce images, though. I think the most basic products like winds, heights, and temperatures will keep coming in the same files as before.

 

[rdale]

Every file name is changing, so if the sites aren't doing something to incorporate they will be blank on that day. However this has been known for months - sites like WeatherBell are already serving up the new data.