"Around July 11, a sharp ridge of high pressure is expected to build in over the Western U.S., bringing the potential for crazy-hot conditions capable of toppling all-time heat records in many western states. "- from Weather Underground co-founder Jeff Masters, in his post The June 2012 U.S. heat wave: one of the greatest in recorded history. He continues,
"The intense heat and lack of rain, combined with soils that dried out early in the year due to lack of snowfall, have led to widespread areas of moderate to extreme drought over much of the nation's grain growing regions, from Kansas to Indiana. The USDA is reporting steadily deteriorating crop conditions for corn and soybeans, and it is likely that a multi-billion dollar drought disaster is underway in the Midwest."
See also Sierra Voices: this is what global warming looks like.