National Hurricane Center meteorologists still hand plot tropical cyclone forecasts on sprawling paper maps of the Atlantic basin, feeling out storm systems in ways predictions spewed by supercomputers can’t.
Satellite data has no wisdom, a keystroke, no empathy.
But the grainy line of a pencil, the ghostly erasure marks of slight track miscalculations, the precise handwriting of a forecaster marking the day and time the swirly center of a potential nightmare was located adds a level of human erudition to the wizardry of modern atmospheric science.
And a basic gut check to the weather models.
“There is a connection there,” said Michael Brennan, the NHC’s hurricane specialist branch chief. “You do have the computer and you can look at all the data on a screen, but there is something to be said about the human interacting with the data, plotting it and thinking about how it’s changed.”
This year, the hurricane center will onlyhand plot only hurricanes that could affect land — a break from decades of tradition but a compromise for younger forecasters more comfortable with computers and less inclined to spend time with colored pencils and compasses.
“It’s a bit of a generational gap,” Brennan said. “There are some people who probably would like to get rid of the paper map entirely, and some who would like to use it all the time.”
There was never a question whether hurricanes and tropical storms would be plotted on paper until the early 1990s when the Automated Tropical Cyclone Forecasting System (ATCF) was introduced. The software was developed by the Naval Research Laboratory for the Joint Typhoon Warning Center and was adapted by the National Hurricane Center for tropical cyclone forecasting.
The ATCF cut the time it took to make a forecast from four hours to three, improving efficiency by 25 percent. Updated over the years, it now provides an interactive program that displays storm locations, updates storm tracks, computes intensity information and helps formulate a forecastforecasts.
Meteorologists consider the weather model outputs and guidance to produce their best prediction on track and intensity. At the hurricane center, the center of the storm is plotted on paper and a line drawn to indicate the predicted track. As the storm moves forward, old forecasts are erased, replaced with the new prediction that a meteorologist might tweak after seeing how much it diverges or conforms to the previous forecast.
“While I was at the NHC, we all still very much liked plotting by hand in addition to doing it on the computer,” said Max Mayfield, who was NHC director from 2000 to 2007. “It is much easier to see which fixes were erroneous, such as satellite fixes when there is no well-defined eye.”
Brennan said paper plotting also makes it easier to see storm nuances along the entire track. The map for Hurricane Irma is the length of a loveseat, its path snaking across the tropical Atlantic from its birth on Aug. 30 as a tropical depression off the coast of Africa to it dissipating Sept. 13 in Georgia.
Irma made landfall near Cudjoe Key on Sept. 10 as a Category 4 hurricane with 132 mph winds.
When forecasters look at the old maps, they pick out their handwriting, remembering what day they were on duty, the gravity of the situation, or its levity, such as 2012’s exasperating Hurricane Nadine, which spun around harmlessly in the far off Atlantic for 24 days racking up 88 advisories.
National Hurricane Center meteorologists aren’t alone in hand-drawning forecasts. The Storm Prediction Center (SPC), which is responsible for predicting severe weather outbreaks, such as tornadoes, also hand analyzes weather maps. Some meteorologists in the National Weather Service’s daily forecast offices do the same.
Pablo Santos, the meteorologist in charge at the Miami NWS office, said while it’s a “little old school” he has one forecaster who starts each shift printing out a paper map.
During lastthis week’s outbreak of tornadoes in Texas and Oklahoma, the Storm Prediction Center Tweeted a photo of its hand-drawn forecast.
“No machine could achieve this amount of analysis detail or be able to synthesize the data together in a way that would specifically address the forecast problems,” said Florida State University Meteorology Professor Henry Fuelberg about the SPC’s map.
Fuelberg, 71, said he remembers receiving temperature, wind, pressure and dew point information via teletype machine and plotting it on a weather map. Hand analysis is still taught in meteorology school, but there’s less emphasis put on it, he said.
And while computers are invaluable meteorology tools, he said they will smooth out data if there is an anomaly, possibly missing a small scale hot spot or a cool pool of air, that a human could see.
“Humans still add value so that you have a better forecast,” he said.
For the hurricane center, pulling out the paper mapshas become ritual — the rustling of the accordion-style folds, the Col-erase colored pencils, the whir of the electric sharpener — is a are allsignals that a forecast is getting serious. The the advisories are beginning.
Some traditions newbie hurricane forecasters learn on the job, such as the red pencil is for Air Force gathered data and the blue is for internal satellite fixes from the Tropical Analysis and Forecast Branch. Squares mean it’s satellite data, triangles are aircraft.
In the end, when the storm is over, the cold science is displayed in a colorful storyline full of human error and triumph, a piece of art worth framing, but more often folded up and shut away in a “storm wallet” — the file that holds each system’s history.
"I hope people take comfort in knowing how much human involvement there is in the forecast,” Brennan said. “Will there be a time when we don’t do a paper map? I don’t know.”