Severe Weather Forecast Into Saturday in the Northern Plains, Midwest, and Northeast

Tom Moore
Published: June 10,2016
Severe thunderstorms will become more numerous Friday into the weekend from the Upper Midwest and northern Plains into the Northeast as building heat and humidity interact with an active jet stream.
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The main severe threats will be damaging winds and large hail. The tornado potential appears to be low, but isolated tornadoes can still occur in these situations, particularly with discrete rotating thunderstorms in the late afternoon and evening before activity consolidates into clusters and lines of storms.

Current Radar with Watches and Warnings

(MORE: View National Interactive Radar Map | Difference Between a Watch and a Warning)
Below is our latest forecast thinking on the timing and magnitude of the severe threats, followed by the severe weather setup.
(INTERACTIVE: Your 7-Day Severe Weather Outlook)

Severe Weather Forecast

Friday

• Midwest: Scattered strong to severe storms should fire up in the afternoon in parts of Minnesota, northern Wisconsin and Michigan's Upper Peninsula. This activity should then consolidate into a line of storms pushing southeast Friday night into Wisconsin, Michigan, northern Iowa and northern Illinois. Damaging straight-line winds and hail are the main threats.
• Northern High Plains: Scattered severe storms will fire up in parts of north-central and northeast Montana. Large hail, high wind gusts, and perhaps a tornado or two, are possible.
• Cities: Duluth | Minneapolis | Grand Rapids | Wausau

Friday's Thunderstorm Forecast

Saturday

• Great Lakes, Northeast: A somewhat more widespread threat for severe thunderstorms from Iowa, southern Wisconsin and northern Illinois to southern New England and the Mid-Atlantic states. Again, the main threats will be damaging straight-line winds and hail, but a tornado or two can't be ruled out.
• Northern High Plains: Individual late afternoon t-storms should consolidate into a late night cluster of severe t-storms in the northern High Plains of eastern Montana, and western North Dakota. Large hail, damaging winds and isolated tornadoes are possible.
• Cities: Chicago | Detroit | Cleveland | Buffalo | Pittsburgh | New York | Philadelphia | Washington

Saturday's Thunderstorm Forecast

Severe Setup

The jet stream pattern will be quite exaggerated by the end of the week. A large ridge (northward bulge in the jet stream) will build into western and central Canada. At the same time a trough (southward dip in the jet stream) will be located just off the East Coast of the U.S.
Mid to upper-level winds from the Great Lakes to the Mid-Atlantic will be racing from the northwest to the southeast (often referred to as a "northwest flow" pattern). This pattern is not uncommon in June when high pressure ridges become stronger, but significant troughs can still be in place farther east.
Occasionally, a strong disturbance (or a series of disturbances) can ride down the eastern side of the ridge toward the trough. The disturbance gains strength as it approaches the trough. At the surface, temperature and moisture contrasts along a frontal boundary become enhanced. This creates a more favorable environment for thunderstorm development.

The setup for severe thunderstorms through Saturday couldn't be more classic for June.

Thunderstorms that develop can feed on the dynamics (energy in the atmosphere) created by the disturbance gaining strength. Depending on the situation, strong to severe thunderstorms can develop. These storms are capable of producing large hail and damaging winds.
By Friday, we expect that a disturbance riding down the east side of a high pressure ridge aloft will trigger thunderstorms, some severe, in the Upper Midwest and northern Great Lakes regions.
On Saturday, a stronger disturbance aloft and a frontal boundary at the surface will enhance the threat of severe weather from the lower Great Lakes to the  Middle-Atlantic region.

Severe Wrap-Up

Thursday, June 9

Severe thunderstorms were most concentrated in the northern High Plains, primarily in eastern Montana and North Dakota.
A supercell thunderstorm tracking about 240 miles in about 6 hours produced up to baseball-size, wind-driven hail, damaging crops, busting out windows in at least four homes, and smashing vehicle windshields in Garfield County, Montana.

Photo above of the Garfield County, Montana, supercell was shared to The Weather Channel Facebook page by "Conquer the Storm"Thunderstorm winds were clocked at 77 mph at Minot Air Force Base, North Dakota.

Wednesday, June 8

A cluster of severe thunderstorms produced a swath of damaging winds in parts of the Mid-Atlantic states.
(RECAP: Thousands Without Power in New Jersey, Philly)
Roof damage was reported in southern New Jersey, and over 62,000 customers were without power at one point in the Philadelphia metro area.
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