On December 1, (1918) the aerological data obtained from pilot balloon and kite flights late in the afternoon were telegraphed to the central office of the Weather Bureau from 18 Signal Corps and Weather Bureau aerological stations in the eastern United States. From these data, the first forecast for the New York to Chicago aeroplane mail service was made and telegraphed to Cleveland.

The scope of these bulletins for aviators has been outlined by the Chief of the Weather Bureau as follows. It is expected that the bulletins will contain a brief statement of: (1) current conditions along selected routes, this statement to include: (a) the direction and speed of the wind at different altitudes; (b) altitudes of cloud layers, when these are below 4 kilometers; (c) altitudes at which the greatest help will be given by the winds, or the least resistance will be offered by them, in case opposing winds will be encountered at all altitudes; and (2) a forecast of probable changes in conditions during the succeeding 24 hours.

Monthly Weather Review, v.46, n.10
October 1918 (closed Dec.3, 1918)

(Reprinted from Aerial Age Weekly, New York, Aug. 18, 1919, p. 1048)

Washington, D.C. --- The Weather Bureau has prepared a map of the United States divided into 13 zones, for which forecasts are to be made for aviators and balloon pilots. These forecasts are made twice daily, at 9:30 p.m., and cover conditions for the succeeding 24 hours.

Since July 21, forecasts have been made with the country divided into seven zones, with such satisfactory results that the number of zones has been increased to 13.

The Air Service has sent out the revised map to their active stations throughout the country and the forecast will be forwarded at the time made, it being intended that all cross-country fliers shall be advised of the weather conditions before starting on any contemplated flight, thereby reducing to a minimum the liability of injury to aviators, balloon pilots, passengers, and property, as far as weather conditions are concerned.

Monthly Weather Review, v., n.47
July 1919 (closed Sept 4, 1919)