Plate Nº 93 · recorded October 10, 2026
Earth & ClimateReported finding
Four warning signs predict when a tilted hurricane will strengthen
University of Miami researchers used 1,510 Hurricane Hunter radar flights across 28 seasons to identify four features that signal a tilted tropical cyclone is about to reorganize and intensify.
By Nathan Brooks4 min read731 words
In brief
- Researchers analyzed 1,510 Hurricane Hunter radar analyses spanning 28 hurricane seasons from 1997 to 2024.
- The study was published September 20, 2026, in the Journal of Geophysical Research: Atmospheres.
- Four characteristics favor cyclone alignment: a tight low-level circulation, a tilt positioned favorably relative to wind shear, stronger thunderstorms near the center, and a supportive environment.
- Storms that eventually aligned already looked different about a day beforehand, according to lead author Michael S. Fischer.
- The National Science Foundation supported the work under award No. 2241605.
Scientists analyzing 1,510 radar flights across 28 Atlantic hurricane seasons have identified four features that signal when a tilted tropical cyclone is about to reorganize and grow much stronger, according to a study published September 20, 2026, in the Journal of Geophysical Research: Atmospheres.
Michael S. Fischer of the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science led the research, which draws on nearly three decades of data collected by NOAA Hurricane Hunter aircraft.
Working with colleagues at NOAA's Atlantic Oceanographic and Meteorological Laboratory, Fischer's team examined which storms managed to align their upper and lower circulations—a necessary step before any tropical cyclone can intensify substantially.
What does a "tilted" storm mean?
Tropical cyclones rotate around centers that exist at multiple levels of the atmosphere. When those centers sit directly above one another, the storm is said to be "vertically aligned."
High-altitude winds, known as vertical wind shear, can shove the upper-level center away from the one near the ocean, leaving a leaning structure that usually cannot intensify.
"A tropical cyclone has to stand up straight before it can intensify," Fischer said. "Strong winds higher in the atmosphere can push the top of a storm's circulation away from the center near the ocean surface. Until those centers come back together, the storm usually cannot intensify substantially."
What are the four warning signs?
Using the TC-RADAR archive, which Fischer and colleagues built from Hurricane Hunter radar observations spanning 1997 through 2024, the researchers compared storms that eventually aligned with those that remained tilted.
They found four characteristics that favor realignment:
- A compact, tightly wound circulation close to the ocean surface
- A storm tilt positioned favorably relative to the surrounding vertical wind shear
- Stronger updrafts and heavier rainfall concentrated near the lower-level center
- An environment with warm ocean water, abundant atmospheric moisture, and relatively weak mid-level winds
How early can forecasters spot these clues?
About a day before alignment, Fischer said, the storms that eventually straightened up already looked different from those that stayed tilted.
Those that aligned carried stronger, more tightly wound circulations near the surface and more widespread, vigorous thunderstorms lifting air near that center.
"Our findings suggest those thunderstorms are not simply a sign of organization," Fischer said. "They may also help pull the storm's leaning circulation upright."
Why does a day of warning help?
Rapidly intensifying hurricanes can leave coastal residents and emergency managers with very narrow windows to issue evacuation orders, close ports, or shelter vulnerable populations.
A 24-hour jump in forecast confidence would expand the preparation window.
"Even a modest increase in forecast confidence a day earlier can provide more usable preparation time for communities in a storm's path," Fischer said. "This study gives us real-world evidence about what separates a storm that is becoming organized from one that remains tilted and less capable of strengthening."
How could forecasters use these findings?
Conventional views treat deep thunderstorm activity near a storm's center as a byproduct of an already-organized circulation. The new analysis suggests thunderstorms may play a more active mechanical role, helping to tug a tilted vortex back toward vertical.
The findings point to physical mechanisms that high-resolution forecast models should capture. NOAA reconnaissance aircraft already gather many of the relevant measurements—low-level wind strength, storm size, thunderstorm coverage, and tilt direction—during routine flights.
Forecasters could test whether models reproduce the alignment process correctly, and apply the four features to evaluate disorganized storms in real time.
Who conducted the research?
Lead author Michael S. Fischer is an assistant professor in the Department of Atmospheric Sciences at the Rosenstiel School and a core faculty member of the Frost Institute for Data Science and Computing.
Co-authors include George R. Alvey III of the Cooperative Institute for Marine and Atmospheric Studies and NOAA's Atlantic Oceanographic and Meteorological Laboratory. Deelan Jariwala, who earned bachelor's degrees in meteorology and mathematics from the University of Miami in spring 2026, also contributed. Paul D. Reasor of NOAA's Hurricane Research Division is the fourth co-author.
The National Science Foundation supported the work under award No. 2241605.
The study, titled "To Align or Not to Align? That Is the Question," appeared in Volume 131, Issue 14 of the Journal of Geophysical Research: Atmospheres. The DOI is 10.1029/2025JD045986.
via news.miami.edu (Original)
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