April 30 (Bloomberg) -- Temperatures will top 80 degrees Fahrenheit (27 Celsius) this week across the Midwest and Middle Atlantic, meaning that more energy will be needed to cool homes and businesses, forecasters said.
The areas using the most energy will stretch from Iowa and northern Missouri through Illinois, including Chicago and into Indiana and Ohio, according to David Salmon, owner of Weather Derivatives in Belton, Missouri.
Average temperatures in the region are expected to reach 8 degrees above normal, though rainstorms may keep the heat from building significantly higher, said Matt Rogers, president of Commodity Weather Group LLC in Bethesda, Maryland.
“At times, areas of the Midwest and mid-Atlantic should see temperatures surge into the 80s, a few 90-degree days in St. Louis,” Rogers said in a note to clients today.
Commodities traders watch temperature outlooks and cooling-degree-day forecasts to gauge energy use and demand. About 51 percent of U.S. households use gas for heating, according to the Energy Department, while demand from electricity generators peaks in the summer months to meet air conditioning needs.
Cooling-degree days are calculated by subtracting a base of 65 degrees from the daily average temperature to show energy demand. Higher values mean warmer weather and more energy being used to heat homes and businesses.
The U.S. figure is expected to reach 31 for the week, or 18 more than the same period last year and 20 more than normal, according to the U.S. Climate Prediction Center in Camp Springs, Maryland.
This is the first week in 2012 that the climate center’s forecast for cooling degree days was higher than its outlook for heating degree days. The heating-degree-days value is a similar scale designed to show how much energy is needed to warm homes.
The unsettled weather in the Midwest may lead to a slight chance for severe thunderstorms and gusting winds across the Ohio Valley today, according to the U.S. Storm Prediction Center in Norman, Oklahoma.
There is a 5 percent chance tornadoes will form in northern Texas and western Oklahoma today, the center said.
The warmth in the central U.S. is forecast to last from May 5 to May 9 before temperatures fall to cooler-than-normal levels by mid-May, according to MDA EarthSat Weather in Gaithersburg, Maryland.
The normal average temperature for May 7 in New York is about 60, according to MDA. It’s 55 in Boston, 57 in Chicago, 64 in St. Louis, 68 in Atlanta, 73 in Dallas, 75 in Houston, 55 in Seattle and 65 in Burbank, California.
To contact the reporter on this story: Brian K. Sullivan in Boston at firstname.lastname@example.org
To contact the editor responsible for this story: Dan Stets at email@example.com