'Ridge Rider' Storms Could Bring Severe Weather, Flooding From the Upper Midwest to the Northeast

July 20,2016
A so-called "ridge rider" weather pattern will bring periods of stormy weather to the nation's northern tier through the end of the week. At times, the storms could turn severe with damaging wind gusts.
In addition, torrential downpours may cause flash flooding in some areas.
The term "ridge rider" refers to the disturbances triggering the storminess as they move along the northern periphery of a hot ridge of high pressure aloft. That high-pressure system is the same one responsible for bringing dangerous heat to the Central and Eastern U.S. through this weekend.
(MORE: Dangerous Heat Ahead This Week)

Current Radar, Watches and Warnings

Thunderstorm Forecast

Wednesday Evening

• Forecast: Showers and thunderstorms will spread across parts of the Upper Midwest and into the Great Lakes.
• Impacts: Isolated large hail and damaging wind gusts are possible, especially by the evening hours. Locally heavy rain is also possible
• Cities: Minot, North Dakota | Grand Forks, North Dakota | Minneapolis

Wednesday Evening's Thunderstorm Forecast

Thursday 

• Forecast:  Scattered severe thunderstorms are likely around the Great Lakes
• Impacts: Some storms may turn severe, with large hail damaging wind gusts being the main threats. Locally heavy rain is also possible.
• Cities: Marquette, Michigan | Muskegon, Michigan | Detroit | Cleveland

Thursday's Thunderstorm Forecast

Friday

• Forecast: Storms will spread into the Northeast
• Impacts: A few storms may turn severe, with large hail and damaging wind gusts being the main threats. 
• Cities: Buffalo, New York | Albany, New York | Burlington,Vermont | Boston

Friday's Thunderstorm Forecast

Saturday

• Forecast: The next disturbance will produce another round of severe weather across the Upper Midwest
• Impacts: A few storms may turn severe, with large hail damaging wind gusts being the main threats.
• Cities: Fargo, North Dakota | Duluth, Minnesota | Minneapolis | La Crosse, Wisconsin

Disturbances in the middle portion of the atmosphere ride along the northern periphery of the hot high-pressure system.

Setup For Severe Thunderstorms

A massive ridge of high pressure aloft (bulge in the jet stream) is anchored across a large portion of the nation. Locations underneath this ridge will have a low chance for thunderstorms.
A couple of strong disturbances will ride across the top of this ridge, however, and they will produce thunderstorms and some will turn severe.
The first upper disturbance will trigger thunderstorms, some severe, across parts of the Upper Midwest by Wednesday evening. This system will progress eastward to the Great Lakes on Thursday and into the Northeast by Friday.
The second disturbance will produce another round of scattered severe thunderstorms by Friday night and Saturday across the Upper Midwest.
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