By Alex Sosnowski
Expert Senior Meteorologist, AccuWeather.com
STATE COLLEGE, Pa. — AccuWeather.com reports relief from the record heat wave of 2012 is on the way from Chicago, St. Louis and Nashville, Tenn., to Atlanta, Washington, D.C., and New York City.
Folks passing out from high cooling bills or from no means of getting a break from the heat will soon get atmospheric aid.
The massive high pressure area responsible for the dangerous and relentless heat from the Midwest to the South will soon shift its position enough to allow a breath of fresh air to roll in from central Canada. The core of the heat will settle farther west.
Areas from Minneapolis, Chicago, Detroit and St. Louis will begin the change to less extreme heat this weekend, from northwest to southeast.
Folks from the Ohio Valley to the central Appalachians on south will have to “wait for it,” but the cooler air will get there.
Interestingly, the worst day of the heat in the I-95 corridor and the central Appalachians is likely to be Saturday, July 7. As the cooler air from the northwest begins to make its move, the air will get compressed in the region. When air is compressed, it heats up. If the air is already hot to begin with … well, you get the picture.
Late in the weekend, the cooler air will reach into the Ohio Valley, central Appalachians and New England.
Finally, seasonable air will push slowly into the swath from Atlanta to Washington, D.C., early next week.
The pattern change will mark an end to 100-degree temperatures in many Midwest and Southern locations and to highs well into the 90s in New York City and Philadelphia.
In Chicago, highs in the 80s are forecast Sunday, July 8, into next week, with the same forecast for the nation’s capital next week. In Atlanta, temperatures will trend to near normal in the middle 80s as next week progresses.
The coolest air will be felt from the Upper Midwest to New England, where high temperatures are likely to be in the 70s for many days.
In northern areas, the transition to less extreme heat will be marked with one or more rounds of thunderstorms, prior to a push of less humid air.
In the South as well as many East Coast locations, the trend to less heat is likely to be accomplished by a few days of clouds and thunderstorms. However, humidity levels may stay high or be quick to return next week.
Prior to and during the transition to more “reasonable” temperatures, there is the potential for some of the thunderstorms to be damaging at the local level.
While any non-violent rain and lower temperatures are welcome in the Corn Belt, this is likely to be the case of too little too late for many fields from Ohio to central Iowa on south.
What the region needs, along with a couple of weeks of below-average temperatures, is a couple of days of steady soaking rain. Lower temperatures are forecast, but the rain will fall short of what is needed.
The heat wave of 2012, where 100 degrees is the new 90, will continue a while longer over the middle and eastern parts of the nation, but it has eyes for areas in the West in the days ahead.
Folks in Boise, Idaho, Salt Lake City, Utah, and Spokane, Wash., may soon get a taste of triple-digit temperatures.
Posted July 6, 2012