Summer will officially begin at 7:09 p.m. EDT on Wednesday, and for much of the east, the season will kick off with near-record heat.

A ridge of high pressure was taking shape across the Great Lakes region on Tuesday, the last full day of spring. Afternoon highs in the low to middle 90s were recorded Milwaukee, Chicago and Detroit to Indianapolis, Cincinnati and Louisville.

The heat will be nothing new in this part of the country. All of the aforementioned cities have recorded at least two 90-degree readings so far in 2012, while Detroit has reached the mark five times.

According to Expert Senior Meteorologist Alex Sosnowski, "Chicago has hit the 90-degree mark a dozen times with St. Louis reaching the mark 17 times so far in 2012."

Interestingly, Atlanta, Ga. has had only 4 days of 90-degree temperatures thus far.

As the ridge shifts eastward on Wednesday, heat will arrive in places much less accustomed to these high thermometer readings.

Cities as far north as Boston and Syracuse are forecast to break the 90-degree mark on Wednesday. Pittsburgh, New York City, Philadelphia and Baltimore among others along the I-95 corridor are also expected to receive a harsh welcome to summer.

Wednesday will feature the first 90-degree reading of the year for many cities, a noticeable change from the cool, overcast days that have dominated the last quarter of spring for much of the East.

On Thursday, 90-degree readings will persist in the same region for the first full day of summer.

Unfortunately, the high temperatures in the mid-Atlantic and Northeast will also be accompanied by high humidity (dew point temperatures in the upper 60s and lower 70s). This cocktail, combined with sunshine, wind speed and other factors will result in RealFeel® temperatures at or above 100 degrees during the afternoon.

Some relief will be found in the form of pop-up afternoon and evening thunderstorms, as well as local waterway breezes. However, any storms will be spotty and isolated. Any sea, bay or lake breeze will wane in the evening hours.

From (find the original story here); reprinted with permission.