- The National Weather Service has taken down heat advisories in some states
- High pressure over the Plains is keeping the weather pattern stable, allowing heat to build
- The heat wave could harm crops, especially corn
(CNN) -- A blistering heat wave retreated to the south Wednesday where it's hot enough to fry an egg, bringing some relief to the Ohio Valley and northeastern United States.
Chris McBee, a resident of Norman, Oklahoma, said he was able to fry an egg on the dashboard of his car, using just the heat of the car's interior, which was 181 degrees.
"I tried it; I didn't think it would work," said McBee. "It's been this hot before. ... I (fried an egg) last year where I just did it on the concrete."
Even though it's still really hot in Oklahoma, the number of states under heat advisories has diminished to 10 -- less than half the number earlier in the week.
Dangerous heat is expected across parts of northern Texas through Thursday evening, according to the National Weather Service. Dallas, Fort Worth, Arlington and other areas will experience afternoon heat indices of 105 degrees or more through Thursday.
Other states still sweltering under heat advisories include parts of Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina and a small area in southwest Tennessee.
Memphis residents should expect a heat advisory for the rest of the week, according to the National Weather Service.
In central Oklahoma, temperatures in Lawton and Wichita Falls shot past the 100 mark for the area's 15th consecutive day of triple-digit heat Wednesday.
High demand for water amid the heat wave and problems with soil shrinking as the ground warms has resulted in burst pipes and low water pressure in Oklahoma City. This prompted officials to issue mandatory water-use restrictions for the first time in at least a decade, according to utilities department spokeswoman Debbie Ragan.
More than 200 people have suffered from heat-related emergencies in Tulsa and Oklahoma City since June 17, when the agency issued its first heat alert, said Lara O'Leary, spokeswoman for the Emergency Medical Services Authority of Oklahoma.
The heat has been so extreme that a portion of the Cimarron Turnpike in Pawnee County, Oklahoma, buckled on Sunday, creating a 2-foot ramp that sent a motorcyclist flying 150 feet.
In addition to the discomfort and potential danger, the heat could wreak havoc on crops, especially corn, said Chad Hart, assistant professor of agricultural economics at Iowa State University. The heat wave comes at a sensitive time for corn, he said.
"That's why markets are watching the heat wave. We're entering a period of time when corn pollinates, and so if you get a heat wave in the early to mid-part of July across Iowa, Illinois and Indiana, it can have a big impact," he said.
"The last time we had a big heat wave and drought was in 1988, and that year we saw corn production fall off by over 30% ... so if we think of where we are today with already-high corn prices, a true drought scenario can push prices to highs we've never seen before."
In Oklahoma City, forecasters are calling for nearly another full week of temperatures near or above 100 degrees, threatening to break a 1936 record for 22 consecutive days of such heat.
Nighttime will bring little solace.
While record- and near-record daytime highs are being set, many areas are also experiencing record warm lows at night. For instance, the low temperature of 83 recorded early Tuesday in North Little Rock, Arkansas, set a record for the warmest low in July, Vaccaro said.
The heat has already claimed at least one victim, a 51-year-old man in Granite City, Illinois, who died Sunday because of the excessive heat, according to the Madison County coroner.
Forecasters say people should limit outdoor activity during the hottest portions of the day, wear lightweight clothing, drink plenty of water and be watchful for signs of heat exhaustion, which include heavy sweating, pale and clammy skin, weak pulse, fainting and vomiting.
Other areas of the country not under heat advisories touted record highs Tuesday.
Newark, New Jersey, broke its previous record of 98, set in 1966, when it hit 99 degrees.
JFK Airport and Islip, New York, did the same, reporting 97 and 93 degrees respectively, beating 1993 records of 94 degrees at JFK and 91 in Islip.
CNN's Monica O'Connor, Meteorologist Jacqui Jeras, Ed Payne, Karen Smith and Chelsea Bailey contributed to this report.