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A North American climate boundary is shifting east, with implications for the Plains

I spent a summer in Fort Worth, Texas, where they define the difference between their fair city and their nearest neighbor as “Dallas is where the East peters out, and Fort Worth is where the West begins.” But there is also a climatological difference between the two places, with drier conditions at Fort Worth than in Dallas.

Climatologists have identified a climate boundary in Texas and the Central Plains that is related to what an article in Yale Environment 360 says is “the Rocky Mountains stopping moisture from the Pacific Ocean reaching farther inland, Atlantic winter storms bringing moisture to the eastern half of the U.S., and moisture from the Gulf of Mexico moving north and curving eastward during the summer months.” Historically, this boundary has been located right around the 100th longitude west, just to the west of Fort Worth. But recent studies have shown that this boundary has shifted about 140 miles east due to trends in temperature and rainfall that are making the Fort Worth area as well as other stations along that meridian drier. They don’t discuss it in this paper, but in the Northern Plains conditions are somewhat different, with moister conditions allowing farmers there to plant corn where in the past the climate was only suitable for wheat.

You can read the article at

Climate change has moved the 100th meridian west climatic divide from its historical position (solid line) 140 miles eastward (dotted line) in recent decades. MODIFIED FROM SEAGER ET AL. EARTH INTERACTIONS, 2018