• The federal Energy Information Administration reports that PJM Interconnect, New York Independent System Operator (NYISO) and New England ISO (ISO-NE) had an accurate handle on demand expectations as temperatures rose.
• The agency looked at data the three companies posted on their websites as the hot spell progressed.
• "The publicly available operating and price information provides a fairly detailed picture of the level of electric system stress during heat waves," EIA said.

From the article:

High temperatures moved out of the Midwest into the population centers of the Mid-Atlantic and Northeast regions during June 19-22, 2012, driving up air conditioner use and electricity demand. These events can be tracked in real-time and examined after the fact with information provided by Regional Transmission Organizations (RTOs).