Severe thunderstorms will rumble across portions of the northern Plains later today into tonight. Besides threatening to spoil outdoor plans and making travel messy at times, the storms threaten to cause damage and endanger lives.
Storm Threat in the Plains Today
An area of low pressure is developing over northeastern Montana along the tail end of a cold front dropping southward across the Canadian Prairies. This will serve as the triggering mechanism for the storms, which will develop during the afternoon, while hot and humid air surging into the region acts as fuel.
The thunderstorms will erupt across portions of northeastern Montana, northern South Dakota and northern Minnesota as well as southern portions of Saskatchewan, Manitoba and northwestern Ontario, Canada.
Severe thunderstorms can also erupt farther south during the evening in southeastern Montana, western South Dakota and eastern Wyoming, but the storms will be much more isolated.
Threats will include damaging winds gusts over 60 mph, golf ball-sized hail and even larger and a few tornadoes.
Flash flooding can also occur in heavy downpours, especially in low-lying and poor drainage areas.
Grand Forks and Jamestown, N.D., and International Falls, Minn., are among the cities and towns at risk.
Storm Threat to Shift East into Midweek
Storms will spread farther south and east as the week goes on, bringing the threats of damaging storms to communities from South Dakota to Minnesota, northwestern Wisconsin and portions of the Upper Peninsula of Michigan on Tuesday.
Parts of northern Ontario will also be under the gun of storms.
Again, the most violent storms will ignite during the peak heating hours of the afternoon.
Thunderstorms will spread back into flood-ravaged portions of the Midwest, including portions of Iowa, northern Illinois and southern Wisconsin by Wednesday, following a dry break to start the week.
Chicago and Detroit may be at risk on Wednesday afternoon.
Related to the Story:
As July draws to a close, a storm system swinging up from the Deep South will bring downpours that will break the back of the heat wave in much of the northeastern United States.
A renewed risk of severe weather will threaten portions of the north-central United States into midweek.
Heavy downpours will raise the concern for flash flooding along the Gulf Coast and lower Mississippi Valley through midweek.
A stifling heat wave will remain entrenched across the Northeast much of this week, despite a brief reprieve in humidity for some.
Dangerous heat will surge northward and send temperatures rising across the northwestern United States this week.
Severe thunderstorms rumbled through the Northeast on Monday, lashing the region with damaging winds while also unleashing heavy downpours that triggered flash flooding.
New York/MA (1819)
Two simultaneous cloudbursts, 45 miles apart; A bucket survey claimed 15" of rain fell at Catskill, NY. Highways were completely washed out. One washout started west of the old Albany Post Road and spread eastward across the road until it was 190 feet wide and 80 feet deep in a distance of 160 paces. At Westfield Valley, "suddenly the windows of heaven seemed to have been opened and the rain fell in such torrents that in less than 5 hours, Westfield River rose at least 20 feet above its usual height at low water. The river overflowed its banks with great rapidity and violence, sweeping away every bridge, fence and building which opposed its current."
Pittsburgh, PA (1872)
Cloudburst of 30 minutes followed by a flash flood. Over 133 people drowned on the north side of Butcher Run and Wood's Run.
New Jersey (1892)
Spectacular "double" waterspouts off Barneget Light at heights of 500-600 feet.