Dip in the Jet: More Severe Storms
In a typical May, warm and humid air near the surface is easily found in the Plains. All you need is a southward dip in the jet stream over the Rockies to send jet stream disturbances aloft over this warm, humid air.
Such will be the case into next week.
Pockets of severe thunderstorms are expected each day through Tuesday in the High Plains, as weak disturbances aloft ripple overhead into the Plains.
By the middle of the week, a more significant severe threat is looming.
The difference lies in the potential for a much stronger upper disturbance, or entire jet-stream level trough itself, swinging out into the Plains, where, as we mentioned earlier, warm and humid air will be in place.
While it's much too far out in time to nail down many specifics, due to limits in predictability of severe weather, and forecast differences among weather guidance, here is our current forecast thinking:
More widespread severe thunderstorms, possibly an outbreak, may kick off in the Plains Wednesday.
This more widespread severe episode may continue in parts of the Plains and Midwest Thursday, and perhaps Friday.
The magnitude of the threat for tornadoes remains unclear at this time.
In addition, this slow-moving weather pattern may lead to heavy rainfall totals.
Repeated rounds of heavy rain on a daily basis will likely lead to localized flash flooding and more river flooding.
The flood risk this week will be highest over Iowa and parts of neighboring states.
Iowa and nearby areas could see 4 to 8 inches of rain over the next seven days or so.
With a stout zone of high pressure along the East Coast, severe thunderstorms are not expected to make much eastward progress this week. A warm front may bring some storms to the Northeast Wednesday. But otherwise, the East will remain largely untouched by the turbulent weather over the central states, at least through Friday.
Check back with us at weather.com, The Weather Channel TV and Weather Underground for the latest on this potential severe weather outbreak.