The National Weather Service radar in Buffalo came back online shortly before 11 a.m. today following five days of repairs.
Until last Thursday's breakdown, the radar unit had rotated almost constantly for 22 years.
"Repair of some critical parts which control its rotation is now completed," the weather service announced.
The unit sustained a "major equipment failure" early last Thursday when a malfunctioning gear box caused the radar to stop turning, according to the weather service.
In a case of bad timing, the radar broke as thunderstorms bore down on the Buffalo Niagara region.
The record-breaking storm dropped more than 2.25 inches of rain over Buffalo in under three hours, resulting in flash flooding across the city.
Emergency crews made several "swift water rescues" under viaducts after motorists became trapped in their cars by rising flood waters.
A national support team dispatched to Buffalo completed "extensive" repairs on the radar, the weather service said.
For those who are curious, here's a summary of how the Buffalo WSR-88D radar was fixed. pic.twitter.com/AVXalLp3jP
— NWS Buffalo (@NWSBUFFALO) July 18, 2017
Weather service officials were forced to rely on nearby radar images – from Cleveland and Binghamton among other locations – during the outage.