Hurricane forecasters will soon lose access to government satellite data vital to tracking hurricanes overnight — and to preventing what meteorologists once called a “sunrise surprise,” when a storm unexpectedly strengthens or shifts in the darkness.

Microwave satellite data are key to capturing major changes in a hurricane’s strength, such as when a storm undergoes rapid intensification. But a main source of those data is being abruptly shut off

The Department of Defense on Monday reversed course, temporarily, on canceling the availability of satellite data that is key to monitoring hurricane movements and structures. The data will now be available to hurricane forecasters through July 31, rather than the previous June 30 deadline.