The National Oceanic and Atmospheric Administration confirmed five coronavirus cases among staff members at the Lakeland, Fla., base for its famed “Hurricane Hunter” research aircraft.

The cases raise the possibility that one of the country’s vital early-warning systems could be hobbled during what is already an unusually active hurricane season. Florida is among the states seeing an uptick in coronavirus cases and hospitalizations, possibly related to their early efforts to reopen businesses. On Tuesday, the state tallied its highest to date single-day count of new cases, at 2,783, according to data tracked by The Washington Post.

The five positive tests came back Friday, according to a statement from NOAA spokesman Jonathan Shannon. The sick personnel were last in the facility between June 3 and 8. The base at Lakeland Linder Regional Airport houses the planes NOAA uses to fly into and around the planet’s strongest storms.

These aircraft, two aging civilian versions of the Navy’s P-3 reconnaissance plane and a heavily modified Gulfstream business jet, carry sophisticated scientific instruments, including Doppler radar, to feed up-to-date information on storm intensity and direction to improve computer model projections of a storm. Each of the planes is named after a Muppets character.

The Aircraft Operations Center also uses un-crewed aircraft to gather data in parts of the storm that are too dangerous for even the Hurricane Hunters to venture into.

The work areas belonging to the infected workers “were thoroughly cleaned in accordance with CDC guidelines” June 9, Shannon said.

The diagnoses means that other staff members, possibly including pilots, mechanics and other essential personnel, are now in a two-week quarantine because of exposure to the virus. The weather and oceans agency would not provide details on the job functions of those who tested positive for the virus, citing privacy concerns.

About 110 personnel are assigned to the Aircraft Operations Center, Shannon said.

“Individuals who were known to have been in contact with the employees have been notified of the positive test results, and we have asked them to self-quarantine for 14 days while they await additional test results,” Shannon said.

Keeping covid-19, the disease caused by the virus, out of NOAA facilities that are relied upon during hurricane season has been a significant concern going into the Atlantic hurricane season. Three named storms have already formed, and the agency is forecasting up to 19 storms in total before the season ends Nov. 30. The Aircraft Operations Center has already flown two missions this season, both into Tropical Storm Cristobal, Shannon said.

The coronavirus pandemic is causing the Federal Emergency Management Agency to rethink how it responds to hurricanes, including by moving some of its functions online.

At NOAA, the agency’s aircraft are flying “with the minimum number of crew members necessary to conduct missions,” and there is more cleaning taking place aboard the planes before and after each flight. “Our medical officer is closely monitoring the health and wellness of flight crews and support personnel in accordance with CDC guidelines,” Shannon said.

The research flights can be grueling, lasting about eight hours as the plane repeatedly crosses in and out of the turbulent core of a tropical storm or hurricane, and staff members are usually seated close together in the cabin, operating research equipment.

“The health and safety of our employees and partners is our top priority and we will continue to share COVID-19 information and impacts as they become available,” the agency said in a statement.

NOAA is not the only agency that flies into hurricanes, however. The Air Force’s 53rd Weather Reconnaissance Squadron, based in Biloxi, Miss., flies into these storms with C-130J Hercules aircraft as well.

The National Hurricane Center in Miami is also trying to keep its staff healthy, as are National Weather Service offices in hurricane-prone locations, from Texas to New England. Each NWS office has a designated backup office, including the Hurricane Center, providing the agency with some redundancy during the pandemic.