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Revision as of 14:59, 25 November 2011 by Omar (talk | contribs) (Which NOAA file (time) is active)
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NOAA GFS winds in VR and VORG games

Winds in the game are from NOAA's Global Forecast System

NOAA GFS winds can be obtained from application:
This is a 1 degree resolution forecast, with numerous weather variables, spaced 3 hours and up to 384h. This data is fabricated by a of weather simulation program, using laws of physics and inputs from instruments [which?]. Server responses are in grib 2 format. Variable "wind at 10m" is used. Winds are given by its two U and V components, in latitude/longitude directions.

VORG 11-12 winds for 06Z are extracted from folder YYYYDDMM00, forecast 06.
Time 0 comes from file gfs.t00z.pgrbf06.grib2, time 12 from gfs.t00z.pgrbf18.grib2 and so on.
Winds for 18Z are extracted from folder YYYYDDMM12. Time 0 comes from file gfs.t12z.pgrbf06.grib2, time 12 from gfs.t12z.pgrbf18.grib2. etc.

Note that a new folder is created by NOAA every 6 hours. Only two of the four daily simulations are used in the game. GFS files are added gradually to latest folder during publication. Schedule seems to be:

 forecast      pub time
00 03:30 - 04:30Z <-- used
06 09:30 - 10:30Z
12 15:30 - 16:30Z <-- used
18 21:30 - 22:30Z

This means forecast 0 is already history when publicated, and meant to be used as a interpolation point (in time). Game wind updates are at 6Z and 18Z, approx 2 hours after GFS release.