Now that the unofficial end to summer, Labor Day weekend, has come and gone, Mother Nature is delivering a fresh taste of fall weather across the northern tier just in time for the weekend. This cooler, drier air mass is heading for the East Coast this weekend.

Signs of this change are already occurring across the Dakotas where low temperatures this morning range from the freezing mark at a reporting station in Beach, N.D., to the middle 40s in South International Falls, Minn.

High temperatures will range from the upper 50s to lower 60s across the Minnesota Arrowhead to the lower and middle 70s in the Dakotas. These highs are 10 degrees below average for early September. Once again tonight, low temperatures will drop into the 30s and 40s across the northern tier.

Early to mid-September is the time when the Upper Midwest and western Great Lakes typically experiences its first frost. That date for International Falls, Minn., is today, September 7, while for Duluth, Minn., the first frost typically happens mid-way through September.

Temperatures this low will threaten outdoor gardens and even kill sensitive vegetation. Protect plants by covering them with a layer of mulch, a tarp, blanket, or even putting them in pots and moving them inside at night. Here are a few more useful tips when taking preventative action against near-freezing temperatures.

The cold front bringing this taste of fall to the northern tier will slip into the Ohio Valley today and head to the East Coast on Saturday. Ahead of the front, severe thunderstorms will build across the Midwest.

Places like St. Louis and Indianapolis will climb into the upper 80s ahead of the front today with the threat for gusty winds, hail and even a few tornadoes. In the wake of the front, much cooler 70s will greet the Mid-Mississippi Valley and Midwest on Saturday.

The front will then sweep to the East Coast where the muggy, hot air in place for much of the week will clash with cooler, drier air to spark a round of afternoon severe storms. Temperatures will warm into the upper 80s ahead of the front only to get replaced by much cooler 70s by Sunday for places like Boston, New York City, Washington, D.C., and Richmond, Va.

With the cooler temperatures come the changing fall colors. Although most trees remain quite green, scattered reports are already coming in of low levels of fall foliage across central Minnesota and western Wisconsin. Check back next week for a detailed story on the fall foliage.

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