Palmer Z drought index shows short-term drought levels over different parts of the country.
It's been more than 50 years since a drought this extensive has afflicted the Lower 48 states. That's the conclusion of NOAA's latest report on drought, released today.

Through the end of June, some 56 percent of the continental U.S. was designated in some form of drought, the largest percentage since December, 1956.

"... indicators suggest that the 2012 drought is similar to the 1950s drought in extent, pattern, and intensity, although not in duration," the report said.

Palmer Drought Index - percent of U.S. very dry
The current drought also does not yet compare with the Dust Bowl droughts of the 1930s in terms of duration, or intensity.

Still, severe-to-extreme drought grew 10 percent from late May to late June, reaching 33 percent of the Lower 48, thanks to the third driest June on record.

In historical context, the Weather Channel writes this is the 10th-largest severe drought since 1895, "but the more severe drought categories don't cover quite as much land now as did the droughts of 1988 and the early 2000s," it said.

Exceptionally dry conditions in the cornbelt and soybean belts over the last three months have taken their toll.

"Topsoil has dried out and crops, pastures, and rangeland have deteriorated at a rate rarely seen in the last 18 years," the report said.