Right on cue with the arrival of the first day of summer, the hottest temperatures so far this year are spreading into the Northeast Wednesday and Thursday.  Find out how high temperatures will soar and how long the heat will last below.

Highs in the 90s will be widespread across the Northeast both Wednesday and Thursday.

Locations from Philadelphia to Baltimore andWashington, D.C. could top out in the upper 90s to near 100 degrees over the course of the two days!  When you factor in the humidity, heat index values may near 105 degrees in the Mid-Atlantic.

The hot temperatures will not be just confined to the I-95 corridor.  Interior cities such as Pittsburgh, Pa., Albany, N.Y. and Burlington, Vt. will also surge into the 90s.

Sweltering heat will also persist on Wednesday farther to the west in the Great Lakes and Ohio Valley, including Chicago, Ill., Detroit, Mich., Cleveland, Ohio and Louisville, Ky.

Through Tuesday, Chicago has already seen 12 days in the 90s this year.  The Windy City averages around 17 days in the 90s annually, so they are running well ahead of their average 90-degree day pace.

Many cities over the two-day period will also be within striking distance of their daily record highs.

How Long Will the Heat Last?

Not as Hot Saturday

• Friday Highs
 
• Saturday Highs

The spreading heat is all the result of a dome of high-pressure aloft that has expanded and shifted from out of the central states into the Northeast.  In simple terms, high pressure in the upper levels of the atmosphere means hot temperatures at the surface where you and I live.

A cold front and its associated jet stream dip will move through the Great Lakes helping to weaken this high-pressure system and shift it into the Atlantic by Friday.  As a result, most cities from the Great Lakes to the Northeast will be closer to late-June averages as we close out the week and enter the weekend.