Pepco was scrambling to restore power to about 1,000 customers in Northwest Washington Friday morning after two underground lines failed near 11th and P streets NW.

The power went out overnight, leaving customers without light and, more urgently, without air-conditioning on a day when temperatures are expected to reach the mid-90s with a heavy dose of humidity.

Officials expect to have power restored sometime this morning, but a more exact timetable is not available. The cause of the power outage is unknown.

Additionally, Garrison Elementary School, at 12th and S streets, and Shepherd Elementary, in the 7800 block of 14th Street, are without power and will be closed on Friday. All other D.C. Public Schools are open as scheduled.

City officials said a cooling center was open overnight at Kennedy Recreation Center, 1401 P St. NW, but will close as of 8 a.m. Friday.