AccuWeather.com reports ahigh temperature records have been falling by the wayside so far this year, and the current heat wave now has more, including all-time records in jeopardy.

Never mind highs near 100 degrees. The current heat wave has temperatures pushing 102, 105 even 108 degrees in portions of the Plains, Midwest, South and East.

Meteorologist DJ Hoffman pointed out that as of Thursday, June 28, 2012, more than 20,900 record highs have been broken to date this year.

"We have had over 7,700 more record highs this year, compared to last year, despite 2011's South Central states heat and drought," Hoffman said.

The temperature pattern this year got a jump start from way back at the tail end of the winter. Multiple days of record highs were set from the central Plains and Rockies to the Great Lakes during March. Chicago had nine days in a row of record highs spanning March 14 to 22.

Indianapolis came within 3 degrees of tying their all-time record high of 107 degrees during Thursday with a high of 104 degrees.

Meanwhile, about 130 miles away in the Hoosier State, in Fort Wayne, the temperature tied their all-time record high set during the dust bowl era in 1936 and 1934, as well as during the blistering summer of 1988.

According to Climatologist Jim Rourke, "Other vicious extreme high temperatures Thursday included Russell, Kan., with 110 degrees; St. Louis, Mo., with 108 degrees; Little Rock, Ark., with 107 degrees; Kansas City, Mo., with 106 degrees; Nashville, Tenn., with 105 degrees and Dayton, Ohio, with 102 degrees."

Earlier in the week, all-time records were reached in Colorado, Kansas and Nebraska.

"All of these locations and many others not only broke or tied daily record highs for the date, but also set June all-time record highs during the current heat wave," Rourke said.

During the next couple of days, temperatures are forecast to reach 100 degrees or higher once again in the central and southern Plains to the Ohio Valley. However, even areas in the central and southern Appalachians and the coastal plain in the South and mid-Atlantic will do the same.

Atlanta is on pace to reach or exceed their all-time record high of 105 degrees set on July 17, 1980, before the weekend is over.

Charlotte, N.C., is also on track to reach their all-time record high of 104 degrees set in 1954 and tied in 2007.

It is not impossible that Washington, D.C., will reach their all-time high

According to Long Range Expert Paul Pastelok, "Given the persistence of the large high pressure area producing the heat and dry conditions thus far, this will not be the last of widespread triple-digit readings this summer."

"While the heat will tend to be intermittent from the northern Plains to the Northeast, indications are that more of this sort of thing can continue from the southern and central Plains to the interior South in the coming weeks."

When a temperature has reached or surpassed the highest temperature on "record" for a particular location, it is considered to be an "all-time record high," Pastelok added.

In many cases, temperature records have been kept for 120 years or more in major cities, while some temperature records in smaller cities and towns may only be in the books for a few decades.

Current, official temperature readings are taken at height of about 6 feet off the ground with no direct exposure to the sun or reflection from the sun or warm surfaces.

Many temperature and weather observation sites are located at airfields.

Before the arrival of airfields during the early 1900s, most observations were taken in inner cities, and while they were accurate to where they were located, they would give higher readings than say in a countryside or suburban location, where most airfields exist, due to the heat island effect.

The heat wave is also playing interesting tricks with nighttime temperatures.

Near the outer edge of the heat wave, where a breeze stays up at night and the humidity is elevated, temperatures barely dipped below average daytime highs for the date.

According to Senior Meteorologists Rob Miller, "In Pittsburgh, the temperature never fell below 80 degrees last night. If it fails to do so before midnight, it will be the warmest night in the Steel City since July 21, 1930.

In Des Moines, Iowa, the low temperature on Thursday was a mere 81 degrees. According to the National Weather Service, it was only the second time in 75 years in which the low temperature was 81 degrees or higher. The last time this occurred was on July 12, 1966.

Meanwhile, in the middle of building drought areas of Arkansas, near the center of the high pressure area and a pocket of dry air, the atmosphere is behaving like a desert. At North Little Rock Airport, the temperature began Thursday at 63 degrees, then reached 107 degrees the same afternoon.
By Alex Sosnowski, Expert Senior Meteorologist for AccuWeather.com