Ugnu Kuparuk, AK

Weather Underground midday recap for Tuesday, May 21, 2013.

After a devastating severe weather day in the Plains on Monday, severe weather began to fire up again across the nation's mid-section on Tuesday.

The nearly stationary low over the Northern Plains showed signs of gradual weakening as it shifted eastward toward the Mississippi River Valley on Tuesday, while the system's associated cold front trailed southwestward from the low across the Mid-Mississippi Valley through the Southern Plains. Favorable energy and conditions ahead of the cold front combined with the moisture laden conditions of the nation's mid-section set the stage for multiple clusters of thunderstorms to develop from the Midwest into the Ozarks and the Southern Plains. Portions of north-central/northeastern Texas, southern Arkansas, northwestern Louisiana and far southeastern Oklahoma remained at moderate risk of severe thunderstorm activity as environmental conditions remained favorable for tornadoes, damaging wind gusts, and very large hail. In particular, substantial severe weather was expected across north-central Texas to the

ArkLaTex region this afternoon and evening. Areas surrounding this moderate risk region from the Southern Plains to the Tennessee/Ohio valleys and the Lower Great Lakes/Northeast remained at slight risk of severe thunderstorm development with hail, damaging wind gusts, and isolated tornadoes. In addition to severe storms, heavy rains created chances of flood and possible isolated areas of flash flooding from parts eastern Oklahoma through northern Arkansas.

Meanwhile, areas of heavy rain and widely scattered showers continued near the low in the Northern Plains and Upper Mississippi Valley and near and to the north of a nearly stationary frontal boundary extending out ahead of the system from the Great Lakes into the inland areas of the Northeast. Continued precipitation in already saturated areas of the Northern Plains and Upper Midwest maintain flood concerns from parts of North Dakota into northern Wisconsin.

Elsewhere, scattered showers and thunderstorms picked up across the Mid-Atlantic and southeastern corner of the nation through the afternoon.