Heat Wave Expands to the East Coast; Flash Flooding Likely in the Central Plains into the Midwest; Severe Thunderstorms in the Northeast

Dangerous, prolonged heat is ongoing in the Mid-South to Mid-Mississippi Valley and heat expands into the Northeast for a brief period today. Widely scattered instances of flash flooding due to heavy rains are forecast from northeast Kansas to much of Indiana. Scattered strong to severe thunderstorms are possible across parts of New England, northern Mid-Atlantic, and North Dakota. Read More >

Storm Summary:

On the evening of 24 June 2009, a potent upper level disturbance tracking across the Northern Plains interacted with a moist and unstable airmass over northeastern South Dakota resulting in the development of scattered severe thunderstorms. One brief and weak tornado touchdown was reported in far western Day County near Amsden Lake, however no damage was observed. A second area of wind damage was also reported east of Langford. A NWS team surveyed this damage and concluded that this damage was produced by a “downburst” of straight line winds. Damage in the area was consistent with wind speeds of 70-80 mph.

In addition to the tornadoes, multiple reports of very large hail were received over Brown and Day Counties, including some to the size of tennis balls or baseballs (2.5” diameter). Several vehicles were severely damaged due to the hail. Significant crop damage from the hail was also surveyed. The most widespread crop damage appeared to be concentrated in southeastern Brown County, as well as northern and southeastern Day County (see image with hail swaths below).

Storm Reports: