Severe thunderstorms are forecast within the yellow shaded areas on the above image this afternoon and evening. A more pronounced threat of severe storms, including very large hail, damaging winds and tornadoes, is expected within the red shaded area on the same image.
A line of strong to severe thunderstorms just passed through the Chicago area, and is pressing into northern Indiana and southern Michigan at the moment. This activity is expected to continue East/Southeast into the Ohio Valley portion of the risk area this afternoon. Strong, gusty winds and spotty hail are the primary severe weather threats with this activity.
A more pronounced severe threat is forecast to develop over eastern Montana and into the Dakotas later this afternoon and evening. An upper level weather disturbance approaching from the West will combine with a moist, unstable atmosphere and several surface boundaries to produce severe thunderstorm development by mid to late afternoon. The initial threat area will be eastern Montana, with the threat moving / developing Eastward into adjacent portions of the Dakotas by late afternoon or early evening.
Hail greater than 2" in diameter possible in black hatched area.
Very large hail, damaging winds and a few tornadoes will be possible with this activity. By mid to late evening, the activity is expected to congeal into one or more small clusters or a complex of thunderstorms, at which time damaging winds will become the primary threat as the activity progresses toward the East and/or Southeast.
Other scattered thunderstorms may develop further East/Southeast along a surface boundary into the remainder of the yellow shaded area on the outlook image by late afternoon or early evening, ahead of the main activity back toward the West. Large hail and damaging wind gusts would be the primary threats with this activity.
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