June 9 (Bloomberg) -- Temperatures in New York are forecast to break a 78-year-old record, taxing the electrical grid and raising health concerns before cooler and drier air sweeps through the area overnight.
The high today in Central Park is expected to reach 99 degrees Fahrenheit (37 Celsius), topping a record of 97 set in 1933, said Tim Morrin, a National Weather Service meteorologist in Upton, New York. High temperatures will reach only into the mid-70s this weekend.
“When you go from today to Saturday, you have a swing of 20 to 25 degrees,” Morrin said by telephone. “A roller coaster, I would say.”
Warnings and advisories stretch from New York to northern Virginia, including Washington, Baltimore and Philadelphia, cautioning residents to limit outdoor activities and guard against signs of heat stroke, the weather service said.
A second day of high temperatures will drive electricity demand in New York to the highest level this year, the New York Independent System Operator, manager of the state’s power grid, said late yesterday. Supplies are adequate, it said.
Power usage is expected to reach 31,200 megawatts, enough for 25 million households on an average day, eclipsing peak use yesterday of 30,603 megawatts, the operator said. More than 36,600 megawatts of supply can be tapped as needed, it said. The state power use record is 33,939 megawatts, set Aug. 2, 2006.
Record temperatures were set yesterday in Washington, Baltimore and Philadelphia, according to the weather service. The high in Washington and Baltimore was 99, passing a mark from 1999, and 97 in Philadelphia, topping a 2008 tally.
The cooling-degree-day value in New York yesterday was 19, or 13 above normal. The value, calculated by subtracting a base of 65 degrees from the daily average temperature, is designed to show energy demand. The higher the value, the hotter the weather and the more energy is being used to cool homes and business.
In Baltimore and Philadelphia the value was also 19, or 13 above normal, and in Washington it was 21, or 12 above normal, according to the weather service.
Morrin said a weather front will move through New York overnight and bring high temperatures down into the mid-80s by tomorrow and even cooler in two days.
The normal high temperature in New York is about 77 degrees, according to the weather service. In Philadelphia it’s 79, Washington 82 and Baltimore 81.
Temperatures next week will be nearer to normal in the East and possibly below normal in the six-state New England region, according to Matt Rogers, president of Commodity Weather Group LLC in Bethesda, Maryland.
“Next week is a definite reprieve from recent strong heat levels in the Midwest and East with cooler, rainier conditions,” Rogers said in a note to clients today. “The South should still stay quite hot and humid.”
Rogers’ 6- to 10-day outlook calls for warm air to dominate the southern U.S. in the same time frame from June 14 to June 18. That warm air is expected to spread into the central U.S. from the Great Lakes to Texas from June 19 to June 23.