Hurricane Eta slammed into Nicaragua with maximum sustained winds of 140 mph on Tuesday, but the monstrous hurricane was even stronger Monday evening, when satellite data suggested that the storm contained 190 mph winds near its core. If this were true, that would have made Hurricane Eta one of the strongest storms on record in the North Atlantic Ocean basin.

The storm maxed out the scales for satellite-derived hurricane intensity when it was barely 75 miles offshore and set to make a vicious and catastrophic landfall. Many meteorologists, though not those at the National Hurricane Center in Miami, thought it was a Category 5 storm.

Typically, forecasters studying storms threatening land areas in the Atlantic would be operating with the benefit of aircraft reconnaissance — the planes that fly within the turbulent, towering clouds of the storm, but that was not the case during a crucial window of time Monday night.

In fact, meteorologists were without aircraft observations all day Monday. Because of mechanical issues, three different aircraft either turned around before ever getting near the storm or did not even leave their home airport.

Hurricane hunter aircraft, operated by the U.S. Air Force Reserve and the National Oceanic and Atmospheric Administration (NOAA), did not sample the storm during most of the time it was at peak intensity. Such flights are critical for observing powerful storms and determining their exact wind speeds, air pressure, location, direction of movement and other characteristics that cannot be fully captured by satellites.

Once a hurricane hunter flight finally arrived inside the storm Monday night, lesser winds of high-end Category 4 intensity were found inside the storm. As a result of the lack of aircraft observations, it remains unclear whether Eta ever made it to a Category 5 ranking.

That matters from a statistical standpoint, since Eta would be only the second Category 5 ever to form in the Atlantic during November.

It also matters for human lives, since coastal residents reluctant to leave their homes in the face of an approaching hurricane may be more likely to heed warnings if they learn that the storm is a Category 5, as opposed to a weaker storm.

The NOAA Corps and the Air Force’s weather recon squadron

Two entities are responsible for flying turbulent flights into hurricanes — NOAA and the Air Force Reserve. Commissioned officers of the country’s smallest uniformed service, known as the NOAA Commissioned Officer Corps, fly missions from Lakeland, Fla., while the Air Force operates flights through the 53rd Weather Reconnaissance Squadron, colloquially known as the “Hurricane Hunters.” They’re based at Keesler Air Force Base in Biloxi, Miss.

On Monday, in a rare cascading series of disruptions, each agency canceled a mission at the last minute — days after a different flight was called off. The first one — by a NOAA aircraft nicknamed “Kermit” — was slated to depart the Sunshine State around 10:30 a.m. Monday.

“We had our NOAA hurricane hunter WP-3D Orion,” said Jonathan Shannon, a public affairs specialist at NOAA’s Office of Marine and Aviation Operations. “We had a maintenance issue [Monday morning], we missed that fix, and then the Air Force hurricane hunters were [going to be flying] after that,” he said, referring to the task of getting a “fix,” or observation, from inside a storm.

The only problem? The Air Force plane, a Lockheed C-130 Hercules, also was having problems.

Arguably the most important mission, given the storm’s rapid intensification, it was halted by a mechanical failure Monday evening.

“Sometimes it happens that we have some maintenance issues,” said Jessica Kendziorek, a public affairs officer at the Air Force Reserve’s 403rd Wing at Keesler. “We’ve been flying so many storms. We had one that had gone and come back, but [the crew] got on their spare and went back and completed their mission.”

The first aircraft took off Monday afternoon and had made it just 200 miles into its flight from Keesler when it was first to turn back. By then, the entire day — at least 15 to 18 hours — had passed without any observations from inside the increasingly fearsome hurricane.

By nightfall, Eta was a beast. Satellite-derived wind estimates indicated winds were at extreme speeds — surpassing 180 mph at times. Meteorologists relied on the “Dvorak technique,” which uses satellite signatures to ascertain what might be going on inside a tropical cyclone. The numbers were off the charts, comparable to some of the strongest tropical cyclones on record anywhere in the world.

At 7 p.m. Monday, the National Hurricane Center drew upon this method to peg Eta’s maximum sustained winds at 150 mph, but the storm continued to strengthen on satellite. The Air Force team aboard the replacement C-130 aircraft didn’t make it inside the storm’s core until closer to 9 p.m. Eastern time. But when it did arrive, no Category 5 winds were observed.

So did compounding delays and a lack of observations miss something? Or did satellites overestimate Eta’s intensity? It’s impossible to say for sure, but meteorologists were relieved once data from inside the storm finally started coming in.

“There is no beating data collected in the storm,” said Matt Sitkowski, the science editor in chief at the Weather Channel, via email. “The Air Force and NOAA hurricane hunters are a tremendous asset to the nation’s hurricane warning program. Their data collection efforts are essential to good forecasts and help lead to better warnings for the public.”

Computer model guidance relies heavily on observations from inside storms. NOAA’s planes, for example, feed data from their powerful Doppler radars directly into computer models used to predict the storm’s path and intensity. While models Monday struggled to simulate Eta’s long-term prospects, they came into closer agreement Tuesday after the hurricane hunter’s flight.

If the forecast were more uncertain, repeated failed reconnaissance missions could have had greater forecast implications, which is especially problematic when a storm is threatening a highly populated area.

The National Hurricane Center says the lack of reconnaissance data, a situation that spanned most of Monday, did not impair forecasts.

“We value every piece of reliable data for the forecasting process,” said Dennis Feltgen, a public affairs officer at the National Hurricane Center, in an email. “With continuous data flowing from NOAA satellites and land-based radar in Central America, this brief lapse in aircraft missions — to ensure the safety of the crew members — did not affect our operations.”

It’s been a taxing season for hurricane hunter operations, logistically and in other ways. NOAA’s two WP-3D Orion aircraft have flown a combined 416.7 hours on research and reconnaissance missions, NOAA’s Shannon said. Last season, which included the slow-moving Category 5 Hurricane Dorian, demanded 337.7 flight hours.

A NOAA-operated, specially equipped Gulfstream jet also flew 194 hours this year, compared with roughly 146 last year. The hyperactive season has caused NOAA to blow through its flight budget for this year and draw significantly from next season’s funds.

The Air Force Reserve hurricane hunters in Mississippi have flown 120 missions this season, compared with 190 in 2005, which is tied with 2020 as the busiest Atlantic hurricane season on record.

They have been forced to evacuate their own base four times ahead of landfalling storms. That entails relocating their fleet of roughly 20 aircraft, several of which were at the same time being used for hurricane hunting missions. Furthermore, most of the crew live in that area, which means they were flying recon missions on storms that could harm them or their families, exacting an emotional toll.

The base was hit hard last month during Hurricane Zeta, which roared into Biloxi after making a direct hit on New Orleans.

With limited crews, the mission of moving all the planes is often a mad dash.

“We get 18 hours notice, or 24 hours, to do it,” Kendziorek said. “You’ve [got to] get all of [the planes] moved. You fly people, and you fly them back, then you fly people, you fly them back. … It’s kind of like playing pickup sticks and jacks; you bounce the ball, pick up as many as you can.”

All of these flights, evacuations and more have come amid the coronavirus pandemic, which sickened some NOAA Corps members at the base in Florida.

Jason Samenow and Andrew Freedman contributed to this report.