In the first place it should not miss to be mentioned the marked interest of the director of the National Observatory, engineer José Carlos Millás, aimed to improve the aerologic reconnaissance with pilot globes that were being carried out at Casablanca, Havana, and to supplement them with the launching of radiosondes. This interest was further increased in 1937, when the first national network of radiosonde stations was assembled in the United States (Blair, 1948).

Two years earlier a complete reorganization and decentralization of the American national meteorological service had been made (Dunn and Miller, 1969), with particular emphasis in the system of tropical hurricanes forecasting in the area of the Atlantic Ocean. Well-known meteorologists E. B. CALVERT AND I. R. Tannehill had a protagonist role on it (ibídem).

Few years later (1939), the political and economic situation in the world experienced a severe shock when the German Fascist government, at the head of a militarist block to which Italy and Japan would be integrated, rushed into an aggression war directed to dispute the imperial hegemony with the other European powers and the United States.

This war constituted an element of singular transcendence in the history of meteorology, because, despite its human and material miseries, it propitiated the bases for the quick development of the modern combat aviation in which the long reach bombing aircrafts, the airborne antisubmarine armament, and the airplanes dedicated to the observation and harassment of enemy positions in sea and land played a main part.

The knowledge of the prevailing meteorological conditions in the high levels of the troposphere, and even in the stratosphere, became vital for the effective employment of these weapons and the elaboration of medium and long term forecasts.

Also, the meteorological predictions showed their decisive importance when planning and executing the maneuvers of big fleets integrated by hundred of units, and the operations of naval landing, some of them gigantic, involving up to dozens of thousands of men's and countless ships and airplanes.

In the case of Cuba, the indicated necessity to improve qualitative and quantitatively the meteorological information for military use relates in a direct way with the fact that at the beginning of 1942 the United States entered in the conflict, and they had essential interests in the area of the Caribbean and the intercontinental route through the North Atlantic. The meteorological information had acquired strategic value due to the singular geographical situation of the Cuban archipelago and its proximity to the continental territory of North America.

This way the things, through Mr. Spruille Braden, ambassador of the United States in Havana, an agreement was summed up directed to build at least two airfields in Cuba that served so much to the aims of an operative air unit as to propitiate the training of British and American pilots going to the battle front. Fields located near San Antonio de los Baños, in the province of Havana, and San Julián, in Pinar del Río, were quickly conditioned for these purposes.

As a result of the measures taken in Cuba in connection with the state of war, the Presidential Ordinance 2455, dated August 29 1942, was promulgated by virtue of which the National Observatory of Cuba became subordinated to the military control of the Navy, and its director was invested immediately with the grade of Captain of Corvette (Rep. de Cuba, G. O., 1942).

The relevancy and opportunity of the protection measures that had been taken were fully justified with a fact happened shortly after, when a German submarine torpedoed and sank two ships that navigated on Cuban sea North of Las Tunas. The victims were a small supply ship and the merchant ship “Nikerliner.” Days later, a Kingfisher hydroplane sighted a German submarine, and communicated its position to a convoy integrated by the merchant ships “Wanks”, Honduran, and “Camagüey”, of Cuba. The escort of both ships was in charge of three Cuban submarine hunters, one of which, the CS-13, dropped several depth loads that caused the implosion of the OR-176 submergible and its consequent shipwreck very near key Bay of Cádiz.