Heat Wave For Midwest, Southeast

By Linda Lam
Published: August 23,2014




 
The Midwest and East have not experienced a heat wave yet this summer, but a pattern change has occurred. Our forecast guidance is indicating some more typical summertime heat will continue in the South and from the Plains to the Ohio Valley through this weekend as the jet stream pushes north into Canada.
There were a few record high temperatures set on Thursday, including Fort Myers, Florida with a high of 97 degrees. Record warm low temperature records were set as well with San Antonio, Texas only dropping down to 81 degrees.
The combination of the hot temperatures and high humidity will make it feel oppressive and the length of the heat wave will make it even more dangerous. An excessive heat warning is already in place for the St. Louis area through Sunday for feels-like temperatures up to 110 degrees.
There won't be much relief at night either with low temperatures dropping only into the mid and upper 70s. There could even be a few record-warm low temperatures in Kansas City and St. Louis.
(FORECAST: St. Louis | Indianapolis)
An extended period of above-average temperatures are expected for much of the South as well. Dallas should top out near 100 degrees into the beginning of next week and Atlanta should see high temperatures in the mid 90s through Saturday.
(FORECAST: Dallas | Atlanta | Memphis)
Forecast highs may flirt with daily record highs in the Deep South over the weekend. Highs could push 100 in parts of middle and south Georgia, South Carolina and north Florida. It will be humid as well, making it feel even hotter.
Savannah, Charleston and Jacksonville may reach record high temperatures on Saturday. Record highs are also possible in Memphis and Mobile on Sunday.
(HIGHS MAPS: Fri. | Sat. | Sun.)
For the most part, the Northeast will miss out on the heat. However, parts of the Mid-Atlantic region were just a bit steamy on Thursday. Washington, D.C., reached a high of 90, its 17th 90-degree day of 2014. The nation's capital averages 33 90-degree days through the end of August, so they are well behind the average pace.
(FORECAST: New York | Pittsburgh | Washington, D.C.)

Lack of Heat Waves

Daily record cool temperatures, both cool morning lows and cool afternoon highs, have been quite frequent this summer for much of the eastern half of the nation. Residents of Indiana and Arkansas saw their coolest July on record, and Illinois, Mississippi and Missouri saw their second coolest July.
Little Rock has only seen three days this summer with high temperatures at or above 95 degrees through Sunday. Their average is 16 days each year. The mean high temperature for the month of July was more than 5 degrees below average in Memphis and 2.5 degrees below average in Atlanta.
(MORE: Record Cool July)
Places like Pittsburgh, Indianapolis, Milwaukee, Grand Rapids and Buffalo still have yet to hit 90 degrees this year.
Chicago has seen only 3 days of 90 degree temperatures or higher and the average for a summer is 14. Minneapolis has only seen temperatures at 90 or above twice and the highest temperature recorded was 92 degrees on July 21.
The Midwest overall has not seen too many days with both excessively hot temperatures and high humidity.
The National Weather Service defines a heat wave as a period of abnormally and uncomfortably hot and unusually humid weather. Typically a heat wave lasts two or more days.
The definition for a heat wave from the American Meteorological Society's Glossary of Meteorology is a period of abnormally and uncomfortably hot and usually humid weather. To be considered a heat wave, such a period should last at least one day, but conventionally it lasts from several days to several weeks.
Why have we not seen any heat waves this summer? A dip in the jet stream has been over much of the East this summer, which has allowed cold fronts to push farther south than usual. This has brought the cooler and less humid conditions to the East.

The highest temperature Cleveland has seen this year was 90 degrees on June 17, 18 and 28. Detroit has also seen a shortage of hot days with only two days reaching above 90 degrees.
Temperatures have not been as cool, relative to average, in the Northeast as compared to the Midwest. However, we have not seen any heat waves for Boston or New York either.
A heat wave for much of the Northeast is generally defined as three or more days in a row with temperatures at or above 90 degrees.
Both cities have only climbed over the 90-degree mark four times this year. The first occurrence of a 90-degree day did not even happen until July 2 for both New York and Boston.