When Category 5 monster Hurricane Lane turned north and was bearing down on Hawaii in August, the National Weather Service accurately predicted it would lose power and make no direct hit on the islands.

That forecast was no fluke.

Among the most accurate models meteorologists used last summer was an experimental upgrade to the standard American forecast model known as the Global Forecast System (GFS).

It is experimental no more. This week the National Weather Service unveiled the upgraded model across the U.S., saying it would produce more accurate forecasts of severe weather, winter storms and hurricane path and intensity.

“We’re definitely excited about it,” said Vanessa Almanza, meteorologist in the Honolulu weather forecasting office.

The National Weather Service announced the major upgrade to its flagship weather model Wednesday, the first significant improvement to the model’s dynamical core, the engine that computes wind and air pressure, in 40 years.

“This is a major milestone in our ongoing effort to deliver the very best forecast products and services to the nation,” Neil Jacobs, acting administrator of the National Oceanic and Atmospheric Administration, said in a press briefing.

Weather officials describe the new and improved forecasting tool as if they were rolling out a new car model.

The upgrade, a press release says, “brings together the superior dynamics of global climate modeling with day-to-day reliability and speed of operational numerical weather prediction. Additional enhancements to the science that produce rain and snow in the model also contribute to the improved forecasting capability of this upgrade.”

Short-term benefits, they said, include improved information about the jet stream and affected weather, rainfall, tropical cyclone intensity and five-day track modeling.

The upgrade also lays a solid foundation to enable future model improvements, they said.

In Honolulu the upgraded model in its experimental form outperformed all established models during the forecasting of Hurricane Lane, according to data obtained by the Washington Post.

The upgraded GFS produced the most accurate forecasts made four (96 hours) and five (120 hours) days into the future, and was comparable with the leading European model and National Hurricane Center forecasts within 72 hours.

Meanwhile the standard version of the GFS model had the worst forecast performance all along the way, the Post reported, while the related Hurricane Weather Research and Forecasting model, a specialized model for hurricanes, ranked second to last.

Derek Wroe, Honolulu lead forecaster and hurricane specialist with the Central Pacific Hurricane Center, said the track for Lane was one of the most complex and challenging forecasts his office had ever seen.

“Going back and performing an analysis on the performance of the new GFS provided valuable data that improves confidence going forward,” Wroe said in an email.

To prepare for the new sophisticated weather model, NOAA significantly upgraded its computing capacity at the beginning of 2018, increasing performance by nearly 50% and adding 60% more storage capacity to collect and process weather and climate observations.

The new capacity allowed for parallel testing of the model throughout the year, officials said, and it clearly outperformed the standard GFS model on a number of occasions. They include intensity forecasts for Hurricane Florence in September, snowfall forecasts during the January 2018 “bomb cyclone” in New England and predictions of widespread heavy rain during a huge West Coast storm in March 2018.

Almanza said the new model runs faster, allowing forecasters to consider even more weather variables.

“It will allow us to input more of what’s happening now to learn what’s happening in the future,” she said.

But the improved GFS isn’t the only recent significant technological upgrade helping forecasters, she said.

The GOES-17 satellite covering Hawaii, Alaska and much of the Pacific Ocean began beaming high-resolution visible and infrared images in November, allowing forecasters to track clouds, atmospheric motion, convection, land surface temperatures, fire and smoke, volcanic ash and more.

“We’re definitely looking forward to how this all comes together,” Almanza said.

The old version of the GFS model will no longer be used in day-to-day operations, officials said, although it will continue to run in parallel through September, offering additional opportunity to compare performance.