The National Hurricane Center successfully predicted Hurricane Idalia’s dramatic intensification during the 24 hours leading up to landfall, a major advance from where forecast skill was just several years ago, Andrew writes.
The big picture: The storm illustrates how NHC forecasters’ capabilities are largely keeping pace despite climate-change related trends in rapid intensification.
- “While climate change makes certain kinds of forecasts (like hurricane intensity) harder, our techniques for making skillful forecasts are improving even faster,” MIT meteorologist Kerry Emanuel told Axios via email.
Between the lines: Storm intensity forecasts have long lagged behind NHC’s improved skill at making track projections.
- But now the investment in new computer models that aim to better resolve small-scale features in the core of a tropical storm or hurricane may be making a clear difference.
- For example, these models, fed with Hurricane Hunter data, consistently showed a “caution” flag for Idalia’s intensification.
- With this storm, nearly every single indicator showed the same scenario: the Jacuzzi-like waters of the Gulf of Mexico plus favorable atmospheric conditions would allow it to rapidly intensify.
Yes, but: The Hurricane Center’s forecasts for Idalia were not perfect.
- Three days in advance, which is within the window when evacuation and other crucial planning decisions need to be made, it was predicted to be a Category 1 storm at landfall.
- At 5am ET on Sunday, NHC meteorologist Eric Blake sounded the alarm in a technical forecast discussion that caught the attention of meteorologists and emergency managers outside of NHC.
- “There’s a notable risk of rapid intensification while the system moves across the record warm eastern and northeastern Gulf of Mexico,” he wrote.
- The official forecast at the time was for a 90-mile-per-hour Category 1 storm at landfall.
Of note: It wasn’t until about 48 hours before landfall that NHC’s forecast was brought in line with the eventual outcome of a Category 3 hurricane hitting Florida.
- In the end, Hurricane Idalia’s top sustained winds increased by 55 mph in 24 hours, greatly exceeding the 35-mph increase needed to meet the definition of rapid intensification.
- But this also exceeded NHC’s 45-mph predicted intensity increase.
The intrigue: Idalia’s example showcases the improvements forecasters, modelers and researchers have made to better predict a phenomenon that is becoming more common and pronounced as the world warms.
- Climate change trends are providing more opportunities for storms to rapidly intensify when other conditions allow due to increasing sea and air temperatures and the related higher amount of water vapor in the atmosphere.
The bottom line: The popular assumption that because the weather is becoming more extreme it is getting harder to predict did not hold up with Idalia.
