A potent storm system,, currently centered over southwestern South Dakota, dropped snow across the Western mountains and is now bringing heavy rain along a broad swath of the South-Central States. Its leading cold front sweeps from the Southern Plains to the Upper Midwest, focusing the clash of cold, dry and warm, humid air masses that ignite the thunderstorms.
Adding to the risk of flooding, especially in Texas and southern Oklahoma, is a plume of tropical moisture, injected by Hurricane Pamela that has made landfall near Mazatlan, Mexico. Combined with Gulf of Mexico moisture that is streaming northward ahead of the cold front, this atmospheric river may bring torrential rain to the Southern Plains.
According to the current forecast, the flood risk will begin this evening and continue through the night. While the mountain snows were more than welcome, especially in the midst of a prolonged Western drought, the heavy rains will fall across a region already saturated by summer hurricanes and early autumn thunderstorms.
