The US Air Force and Navy are having problems agreeing on how to coordinate their weather forecasting efforts. This has become more crucial as each service obtains more aircraft that can operate in bad weather, and there are more operations involving air force and navy warplanes. The problem was first noted during the 1991 Gulf War, although even during the Vietnam war there were similar problems. During the 1999 campaign against in Kosovo, the weather was a particularly crucial issue. During the 78 day campaign, only 24 had clear weather. The persistent cloud cover prevented warplanes from finding and identifying targets 30 percent of the time. The navy used cloud penetrating radar to identify targets, but this capability was not used by the air force, which was in charge of the overall campaign. The air never bothered to ask the navy if they had this capability, and the navy never volunteered the information (or at least no one in the air force will admit they did.) After this, the Pentagon ordered the air force and navy to cooperate on how they dealt with weather. While both services have agreed that such cooperation is a good thing, both have dragged their heels over many issues. Things get particularly sticky when it comes to spending more money or doing things differently. The issue is still unresolved.