HAARP, Infrared lasers, cloud seeding, all have been the subject of research for decades in weather modification. In fact, there is an initiated measure in my county this election to abolish cloud seeding (weather modification).
Keeping in mind that weather has played pivotal roles in battles in the past, from the Kamikaze winds, to the typhoon the US fleet went through in WWII, the military was/is interested in being able to generate storms which would interfere with an enemy's troop movements, and possibly cause devastation to their forces.