Introduction to Severe Geomagnetic Storms
The NOAA Space Weather Prediction Center has confirmed that severe G4 geomagnetic storm conditions have already been reached following the impact of a coronal mass ejection striking Earth.
Simultaneously, a severe S4 solar radiation storm continues, the first of this level since 2003. NOAA has maintained a warning for a Kp index of 7 or greater through Tuesday.
Understanding the S and G Scales
It’s essential to understand the context of these storms. The S scale refers to solar radiation storms, associated with intense flows of high-energy protons from the Sun. An S4 event, classified as severe, can primarily affect aviation on polar routes, space operations, launches, and satellites. According to NOAA, expected impacts from this event are mostly limited to these technical sectors and not the surface population.
Geomagnetic Storms and Their Impacts
The G scale, on the other hand, measures geomagnetic storms, which occur when those solar particles interact with Earth’s magnetic field. A G4 event corresponds to a Kp near 7 or 8 and is the type of storm that can extend aurora visibility much further south than usual, in addition to causing disruptions in satellites, GPS, and other technological systems. Weather Meteorologist Deric Hartigan, Weather Meteorologist Sean Batty, and Weather Meteorologist Maurice Middendorp are closely monitoring the situation.
Will it be Visible in Florida?
This scenario is already being reflected in real observations. In recent hours, there have been reports of visible auroras across much of Europe, including Scotland, Ireland, and the Netherlands, among other countries. These observations confirm that the geomagnetic storm is intense enough to produce auroras at mid-latitudes.
Understanding the Kp Index
To know whether the aurora could reach Florida Monday night, it’s useful to understand the Kp index, a scale from 0 to 9 that measures the intensity of geomagnetic storms. A Kp index close to 8, characteristic of a G4 storm, is high and uncommon. When the Kp reaches such levels, the area where the aurora can be seen expands significantly southward.
Past Observations
This has happened recently. In late November 2025, a severe geomagnetic storm allowed auroras to be reported even in parts of southwestern and central Florida. In those instances, what was observed were not bright lights at the top of the sky, but a faint glow, usually reddish and sometimes slightly greenish, very low on the northern horizon, mainly visible from areas with dark skies.
Possibility of Aurora Visibility in Florida
So, is it possible that Florida will see auroras again Monday night? The answer is that there’s a possibility, but it’s not guaranteed. It will all depend on whether the storm reaches its peak intensity and how it interacts with the Earth’s magnetic field when it arrives. If conditions align as they have in past events, one cannot rule out a faint glow on the northern horizon, especially from locations with minimal light pollution and clear skies.
Conclusion
In summary, this is an uncommon event because it coincides with two different severe storms. The S4, related to solar radiation and effects on space and aviation, and the G4, related to Earth’s magnetic field response and the expansion of auroras. NOAA will continue monitoring the event’s progression and updating its forecasts as new data becomes available.
FAQs
- Q: What is a G4 geomagnetic storm?
A: A G4 geomagnetic storm is a severe storm that can extend aurora visibility further south than usual and cause disruptions in satellites, GPS, and other technological systems. - Q: Will the aurora be visible in Florida?
A: There’s a possibility but it’s not guaranteed. The visibility depends on the storm’s peak intensity and its interaction with Earth’s magnetic field. - Q: What is the Kp index?
A: The Kp index is a scale from 0 to 9 that measures the intensity of geomagnetic storms. A high Kp index indicates a more intense storm. - Q: How does the S4 solar radiation storm affect us?
A: The S4 solar radiation storm primarily affects aviation on polar routes, space operations, launches, and satellites, with minimal impact expected on the surface population.
