Drought area expands in northern U.S., eases in south

* Rains help parts of southern Midwest, south-central U.S.
* Dry weather expands drought in Dakotas, upper Midwest
* Dryness expands in Texas/Oklahoma panhandle

Sept 20 (Reuters) - The worst drought to hit the United
States in a half century expanded in the upper Midwest and
northern Plains states in the past week due to warmer- and
drier-than-normal weather, but loosened its grip on some central
and southern areas of the country.
Nearly 65 percent of the contiguous United States were under
at least "moderate" drought as of Sept. 18, up from about 64
percent a week earlier, according to the Drought Monitor, a
weekly compilation of data gathered by federal and academic
scientists.
However, the portion of the country under "exceptional"
drought - the most dire classification - declined slightly to
5.96 percent from 6.23 percent a week earlier.

"This U.S. Drought Monitor week saw some improvements in
drought conditions in portions of the lower Midwest, Southern
Plains, and the South while drought-stricken areas of the
Northern Great Plains and upper Midwest continued in a dry
pattern leading to some minor degradation of conditions," David
Simeral of the Western Regional Climate Center, said.
Conditions in southern Illinois and Indiana and eastern
Kentucky, some of the worst-hit drought areas this summer,
improved with heavy rainfall over the past month, including
precipitation from a Hurricane Isaac.
But warmer and drier-than-normal conditions parched central
and northern Minnesota and Wisconsin - states that dodged the
worst of the summer's drought.
Overall, the nine-state Midwest region saw its
moderate-or-worse drought area shrink to 39.25 percent, from
40.80 percent a week earlier, the Drought Monitor showed.
Moderate drought expanded in the Dakotas amid below-normal
precipitation across most of the central and northern Plains,
although conditions improved in southeastern Kansas, which
received rain.
The area of the High Plains consumed by moderate drought or
worse inched up to 82.81 percent from 82.77 percent a week
earlier, but the area gripped by exceptional drought shrunk to
23.71 percent, from 25.10 percent.
In the south-central United States, the drought grew more
dire in the Texas and Oklahoma panhandle region but eased
considerably in Arkansas, half of which was under "exceptional"
drought just a month ago.
The region as a whole saw its moderate drought area slip to
48.67 percent from 49.00 percent a week earlier and the area
covered by exceptional drought held about steady at nearly 9
percent.
Exceptional drought covered 42.09 percent of Oklahoma, up
from 39.66 percent a week ago, and 8.74 percent of Arkansas,
down from 12.06 percent a week ago and 53.60 percent a month
ago.

(Reporting by Karl Plume in Chicago; Editing by Maureen Bavdek)