Próbáltam keresgélni, és egy ezer éves fórumbejegyzésben ezt írták: "Weather balloons, measuring the true state of the atmosphere, are only sent up for the 00Z and 12Z runs of the models. During these intermediate periods, satellite or other estimations of the atmosphere's content are used. Although that data is more granular (satellites can see everywhere, upper-air sounding stations -- balloon stations -- are hundreds of miles apart), it tends to disagree with the previous manually-measured atmospheric conditions. This is either because the data really is more inaccurate, or we just haven't learned the right equations to handle it in the computer models."