How long will summer hang on in the midwestern, northeastern US?

A blast of cool air will erase the summerlike heat in the midwestern and northeastern United States this week.

Friday marked the official start of autumn, but summer decided to hang around or finally show up across the eastern half of the nation.

Many areas from the Mississippi Valley to much of the Northeast can expect more 90-degree Fahrenheit weather into midweek.

Temperatures will be held down a few degrees east of the Appalachian Mountains on Wednesday. However, an increase in humidity as Maria approaches will make the air feel just as hot as Monday.

Typically in late September, temperatures top out in the 60s in northern New England and the upper Great Lakes to the 70s elsewhere in the Northeast and Midwest.

Air flowing in from the Atlantic will keep Boston and the rest of the immediate East Coast cooler than inland areas.

However, beachgoers will need to use caution as Maria will cause surf and the threat for rip currents to gradually build to dangerous levels for swimmers and operators of small craft through midweek.

For those who have already put away window air conditioning units and/or are looking for true fall weather, relief is coming later this week.

"The same cold front responsible for eventually steering Maria out to sea will be the front that breaks this streak of record-breaking heat across the Midwest and Northeast by the end of the week," AccuWeather Senior Meteorologist Dan Pydynowski said.

A cold front marks the leading edge of advancing cooler or colder air.

The much cooler air will reach the central Great Lakes on Wednesday, ending what is expected to be a seven-day stretch of 90-degree heat for Chicago.

The cooler air will continue to advance to the south and east, trimming temperatures and humidity values along the I-95 corridor by Thursday and Friday. Part of the South, down to around the I-20 corridor, will feel a reduction in humidity levels to close out September.

Highs later this week will be 10-20 degrees below what will be recorded on Monday.

Despite whisking the summer warmth away, the front will not dramatically end the dry streak that has unfolded amid this warm spell in most areas.

While raising the risk for flooding across the Plains, the front will struggle to produce meaningful rainfall as it crosses most of the Midwest and Northeast.

The exceptions will be around Lake Superior and the St. Lawrence Valley. If Maria tracks close enough to North Carolina, its moisture may interact with the front to cause an increase in showers and thunderstorms along the Northeast coast.

Abnormally dry to moderate drought conditions are occurring from the mid-Mississippi Valley to the lower Great Lakes, according to the U.S. Drought Monitor.

“If Chicago does not receive any more rain this month, it would be the fourth driest September on record,” AccuWeather Meteorologist Brett Rathbun said. “Chicago has only received 0.32 of an inch of rain this month.”

In the front’s wake, a reinforcing shot of cooler air may be accompanied by showers across the Great Lakes, but these showers are not likely to produce a significant amount of rain.

By the end of the week the heat will have been erased over much of the eastern half of the nation.

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