As the powerful category-4 storm slammed into the island, it rendered the Federal Aviation Administration’s two Doppler radars – which supported NOAA’s weather forecasts – inoperable. NOAA and the Department of Defense teamed up stateside with coordination through FEMA to deploy two U.S. Marine Corps radar units temporarily to the island while the FAA radars are being assessed and repaired.

The short-range, X-band Doppler radars, along with U.S. Marine Corps meteorologists and radar technicians to operate the equipment, arrived in San Juan by military C-130 aircraft on Oct. 21. After a brief installation and testing phase at Roosevelt Roads, one unit remains there and the other deployed to Aguadilla, providing radar coverage for both the eastern and western parts of the island.

“Hurricane Maria left a massive data gap that hindered our weather forecast and warning operations on Puerto Rico and the U.S. Virgin Islands,” said RDML Tim Gallaudet, Ph.D., USN Ret., Assistant Secretary of Commerce for Oceans and Atmosphere and Acting Under Secretary of Commerce for Oceans and Atmosphere. “This significant collaboration across the federal government has restored our ability to serve 3.5 million people with early warnings and improved precipitation forecasts in the interim until the FAA radars are restored.”

“Relief efforts in Puerto Rico will be able to operate more freely and efficiently with Marine Corps and Air Force forecasters collaborating in a joint effort to accurately forecast meteorological impacts to ongoing operations,” said Warrant Officer Adam Harmon, Marine Corps Control Squadron-2 Detachment officer in charge.

In addition to the Marine technicians deployed to support the new radars, NOAA sent personnel from the National Weather Service Radar Operations Center in Norman, Oklahoma, with equipment to connect the radars to a satellite uplink so the radar imagery can flow seamlessly through the NWS forecast system. In coordination with personnel from the National Weather Service Forecast Office in San Juan, these teams are restoring important public safety infrastructure on the island.

The two DOD radars are a temporary solution in Puerto Rico and the USVI. While these mobile radars will support public safety, they are not a permanent solution because they have limited scope. This mission has been authorized by FEMA through Nov. 24, with the possibility of further extensions until FAA’s WSR-88D radar has been returned to service.

NOAA personnel also are working with the FAA to restore communications with the FAA Terminal Doppler Radar at Punta Salinas Air Guard Station, just west of San Juan. The radar is functional, but lost its communication link to the NWS forecast system during the hurricane.