Plate Nº 78 · recorded October 16, 2026
Earth & ClimateReported finding
NASA Spots Atmospheric Gravity Waves Rippling Above Hurricane Simon
Hurricane Simon hit Category 4 with winds of 250 km/h on October 11, 2026, as NASA satellites captured rare atmospheric gravity waves rippling high above the storm.
By James Calloway3 min read589 words
In brief
- Hurricane Simon reached Category 4 strength on October 11, 2026, with sustained winds of 250 km/h (155 mph).
- By the time VIIRS aboard Suomi NPP captured Simon at roughly 2:30 p.m. local time on October 11, sustained winds had dropped to about 210 km/h (130 mph).
- NOAA-21's VIIRS detected atmospheric gravity waves spreading outward from Simon during the early morning hours of October 11, 2026.
- On October 13, 2026, the National Hurricane Center described its intensity and track forecasts for Simon as 'very low confidence.'
- Simon's eye sat about 50 kilometers (30 miles) offshore between Manzanillo and Puerto Vallarta when it was imaged.
Hurricane Simon hit Category 4 strength on October 11, 2026, packing sustained winds of 250 kilometers per hour (155 mph) as it tracked along Mexico's Pacific coast. Even after weakening, the storm sent ripples high enough to light up Earth's upper atmosphere — and NASA's satellites were watching.
By roughly 2:30 p.m. local time (20:30 UTC), the VIIRS instrument aboard NASA's Suomi NPP satellite snapped an image of Simon's eye about 50 kilometers (30 miles) offshore, sitting between Manzanillo and Puerto Vallarta. Sustained winds had dropped to around 210 km/h (130 mph), the National Hurricane Center reported. Still destructive. Still dangerous. Just no longer the storm it had been hours earlier.
What did Simon do on the ground?
Simon never officially crossed the coastline. The Sierra Madre mountains took some of the bite out of the system, weakening the inner core and shrinking the wind field. That reprieve was partial. The hurricane still dropped torrential rain on the port city of Manzanillo and raised mudslide risks across mountainous terrain, according to news reports at the time.
Why did satellites see waves above the clouds?
Atmospheric gravity waves are not ocean waves. They are ripples in the air itself — disturbances where gravity acts as the restoring force, much like a buoy bobbing in water. Powerful storms can punch these patterns upward, all the way into the stratosphere and mesosphere.
Near Simon's eyewall, the release of latent heat (energy stored in moist air that escapes when water vapor condenses) drove towering cumulonimbus clouds skyward. Those updrafts shoved the surrounding atmosphere hard enough to launch wave after wave overhead.
A separate satellite, NOAA-21, caught the signatures during the early morning of October 11. The VIIRS day-night band picked up variations in airglow — a faint, natural glow produced by gases high in Earth's atmosphere — that traced the wave patterns overhead.
Why don't we see this more often?
Strong upper-atmosphere winds normally shred these disturbances before they become visible. Clear imaging demands near-ideal conditions.
Three things lined up on October 11:
- Simon generated waves energetic enough to climb high
- The waves survived long enough to reach the airglow layer
- The Moon was dim, so reflected light didn't wash out the signal
Rare sight. The kind that rewards being in the right orbit at the right hour.
What does this change for forecasters — or the rest of us?
Practically speaking, not much. Gravity waves above hurricanes are a curiosity. Scientists track them because they mark how violently a storm is venting energy upward. Operational forecasting tools they are not — at least not yet.
The bigger story from Simon was forecast confidence — or the lack of it. By the morning of October 13, the National Hurricane Center described its intensity and track predictions as "very low confidence." One scenario had the storm curving north into the Gulf of California and eventually making landfall. Nobody could rule it out. Large ocean swells were already chewing at Mexico's southwestern and west-central coastlines.
Caveats worth keeping
One storm. One detection window. NASA and NOAA have caught gravity waves above other tropical cyclones before, so the phenomenon itself isn't new — Simon just offered an unusually clean snapshot.
The Sierra Madre effect on intensity is also storm-specific. Flat-terrain hurricanes don't get the same dampening. And a "very low confidence" forecast is not a forecast of disaster. It's a forecast of uncertainty. Plan for the range, not the point.
via reuters.com (Original)
More from James Calloway
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Staff writer covering regulation, policy and their impact on general science news at SciBeat.
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