* Temperatures to reach 100 degrees in Chicago * Demand high but not expected to reach record levels * Con Edison continues to talk with union workers July 16 (Reuters) - The power grids in the U.S. Midwest and Northeast said they have more than enough resources to keep the lights on this week as homes and businesses crank up their air conditioners to escape another brutal heat wave. The grid operators said power usage would be high but was not expected to break any demand records. High temperatures in Chicago were expected to reach 96 degrees Fahrenheit (36 Celsius) on Monday and 100 on Tuesday before dropping to near normal levels in the mid 80s on Wednesday, according to AccuWeather.com. In New York, the mercury was expected to hit 92 degrees on Monday, 95 on Tuesday and 94 on Wednesday before falling to near normal levels in the 80s on Thursday, AccuWeather.com said. New York power company Consolidated Edison Inc, which locked out its 8,000 member union workforce on July 1 due to a contract dispute, asked its 3.2 million customers in New York City and Westchester County to conserve power during the heat wave but had not imposed any voltage reductions. During the last two heat waves that baked the Big Apple this summer, Con Edison reduced the voltage, also known as a brown out, in several neighborhoods to take the load off the system and allow workers to fix heat stressed equipment. The company said past voltage reductions had nothing to do with the lockout, noting the company reduced the voltage before the lockout and after. The company and union were expected to meet again later Monday. The two regions where the power usage will get closest to past demand records this week were New York and the Midwest. The Midwest Independent Transmission System Operator (MISO), which operates the power grid in all or parts of 11 U.S. Midwest states and the province of Manitoba in Canada, forecast demand would approach 96,600 megawatts (MW) on Tuesday, which is close to the system's all-time peak of 98,526 MW in July 2011. The New York ISO (NYISO), which operates the grid in New York State, forecast demand Tuesday would approach 31,900 MW, which is still below the state's all-time peak of 33,939 MW in August 2006 before the recession of the late 2000s cut mostly industrial and commercial demand for power. One megawatt can power about 1,000 homes. CONSERVATION URGED To take some of the stress off the system, some grid operators have already asked generators and transmission owners to put off unnecessary maintenance and some local utilities, like Con Edison, have called on consumers to conserve power during the heat wave. Later in the day as temperatures rise, some utilities may also call on customers who signed up for demand response programs to reduce power usage. Demand response programs pay consumers to cut back on electric use during peak times or when power prices are high by shutting off unnecessary lights, elevators and other equipment, reducing air conditioning and even turning on backup generators to reduce the amount of power they take from the grid. The biggest power companies in the regions baking in the latest heat wave include units of Duke Energy, Exelon Corp, FirstEnergy Corp, American Electric Power Co Inc, Xcel Energy Inc, Con Edison, National Grid PLC and Northeast Utilities.