June 2009 North America jet stream
© AccuWeather

The weather across large portions of the United States and Canada has been rather strange recently with extremes on both ends of the spectrum.

The main reason for the unusual weather has been the position of the jet stream. The jet stream has been pushed farther to the south than normal due to high pressure blocking in the far northern latitudes. These blocks have forced unseasonably chilly air into the Northern states and parts of the West, while unseasonably warm and dry weather has persisted from parts of Alaska through British Columbia and Washington state.

The active jet stream cutting across the United States has produced extended periods of wet weather from coast to coast. There has also been a very early start to the western monsoon season, while tropical air has brought heavy rainfall back to the Southeast after a long period of dry weather.