Coronavirus has grounded airplanes worldwide and that’s skewing weather forecasts. Some commercial planes are equipped with special air-sampling equipment that measure storm-stoking ingredients.

Gurgles and gusts high in the atmosphere have stories to tell about future weather patterns at Earth’s surface, but airplanes grounded by coronavirus are collecting less data and leaving holes in forecasts during one of the most active times of the year.

Commercial airplanes equipped with special air-sampling equipment provide an estimated 250 million observations annually that include storm-stoking ingredients such as temperature, wind speed and direction, pressure and humidity.

Worldwide, the number of airplane flights has plummeted 77 percent as of April 7 compared to 2019. In the U.S., flights have been cut by 64 percent during the same time period, according to the flight tracking company Flight Aware.

At Palm Beach International Airport in West Palm Beach, flights are down about 60 percent.

The National Centers for Environmental Prediction, which is part of the National Oceanic and Atmospheric Administration, said it’s too soon to quantify how the loss of aircraft data will affect forecasts, nothing that information is still coming in from cargo and package carriers.

“Even though a decrease in this critical data will possibly negatively impact forecast model skill, it does not necessarily translate into a reduction in forecast accuracy since National Weather Service meteorologists use an entire suite of observations and guidance to produce an actual forecast,” said a statement released by Lauren Gaches, a NOAA spokeswoman.

Still, two South Florida meteorologists said they’ve seen evidence where models flubbed forecasts during specific events that could have been caused by the lack of airplane data, and South Florida Water Management officials are noting that predictions usually reliable out two weeks, may only be accurate for five days.

As of March 31, the daily output of meteorological data from U.S. commercial aircraft was down by half.

“I think the speculation is when the flow is not very challenging, then the prediction isn’t affected, but if the flow is a little complex, the loss of some of this essential data has an impact,” said Todd Kimberlain, senior meteorologist with the South Florida Water Management District. “Aircraft data is an essential component. The models are used to using that data.”

Recent misreadings could have been tied to lack of data from flights

For much of last month, high pressure loitered over Florida, leading to the warmest March on record for the Sunshine State and the second driest.

But a pattern shift late in the month led to three consecutive cycle “dropouts” — forecast busts — from three modeling centers. Kimberlain said it’s rare for all of the models, including the touted European model, to misread the atmosphere.

Meteorologists at the district used the models to predict above normal rainfall in longer-range forecasts. Instead, it was below normal.

“We overpromised and underdelivered,” Kimberlain said. “That doesn’t mean it was a total disaster, but by our benchmarks it was.”

Robert Molleda, warning coordination meteorologist for the National Weather Service in Miami, said models for a recent severe weather forecast misread the atmosphere.

On April 5 the forecast called for scattered showers and thunderstorms that could be severe. Localized flooding, hail and an isolated tornado were considered possible with the strongest storms.

The Miami NWS office, which typically releases two weather balloons each day to sample the atmosphere, sent up a third.

“The balloon data revealed that the models weren’t properly handling the amount of leftover stability over the area, which ended up limiting our threat,” Molleda said. “So perhaps there could have been some influence from the lack of aircraft data providing temperature and humidity data aloft.”

Timing couldn’t be worse for the lack of information

Spring is one of the most combustible times for storms in the southeast as late-season cool fronts clash with the warming air of a newborn season.

On Easter Sunday through early Monday, an area of low pressure and sagging cold front raked through parts of Dixie Alley — tornado-prone areas of Louisiana, Alabama, Mississippi, Tennessee, Georgia and Florida's Panhandle.

Preliminary storm estimates tallied 55 tornado reports, 493 wind reports and 39 reports of large hail. At least two dozen people are believed to have been killed.

Molleda said severe weather events such as Sunday’s could help identify a trend in how the lack of airplane data is affecting forecasts.

“To say the loss is having no effect is unlikely,” Kimberlain said.

The information collected by airplanes is sent to weather agencies around the world through the Aircraft Meteorological Data Relay program, which is operated by the World Meteorological Organization, or WMO.

WMO officials said last week they were concerned about a lack of observations with fewer flights and in developing countries where data collection is not automated. To mitigate the loss of airplane information, some countries, particularly in Europe, have increased the number of balloon launches, according to the WMO.

Still, many meteorologists said the short-term loss of data won’t cause severe sidetracks in forecasts.

“There will be a change, but if you quantify it, it’s probably manageable,” said Jordan Powers, a scientist for the National Center for Atmospheric Research. “I think there are bigger observation sources that are going into the models that are not affected at all.”

NOAA collects billions of data points from sources such as weather balloons, radar, satellites, ships at sea, ocean buoys and surface observations such as from weather stations at airports.

The goal is to get an accurate idea of what the atmosphere looks like at any given moment. The evidence of temperature, wind speed, pressure and humidity at different levels of the atmosphere are plugged into equations based on the fundamental understanding of physics.

A bad observation can act as a domino to topple a forecast, but Jordan said widespread busts are unlikely.

“I think it will be a small difference ultimately,” he said.

Kmiller@pbpost.com

@Kmillerweather

This story originally published to palmbeachpost.com, and was shared to other Florida newspapers in the USA TODAY Network - Florida.