A burst of activity on the sun has raised the odds that the northern lights will be visible well beyond their usual far-northern haunts. Forecasters tracking the incoming disturbance say the aurora could dip into the northern tier of the United States, potentially reaching skies over states as far south as New York and Idaho if the storm arrives as expected.
What sends the aurora south
The northern lights are produced when charged particles from the sun collide with gases high in the atmosphere, releasing the shimmering greens and reds that define the display. Ordinarily that glow is confined to high latitudes near the poles, where the planet’s magnetic field funnels the particles down. The specific colors depend on which gas is struck and at what altitude, with oxygen tending to yield green and red and nitrogen contributing blues and purples. Green, the most common shade, tends to appear at middle altitudes where oxygen is abundant, while the rarer deep-red glow forms much higher up, which is part of why a display seen from far south often shows red light spilling over the horizon even when the brighter green curtains stay out of view. The interplay of those colors is what gives a strong aurora its shifting, layered appearance.
A geomagnetic storm changes the picture by energizing that interaction and pushing the auroral oval toward lower latitudes, which is why a strong storm can make the lights visible in places that rarely see them, according to a forecast of the aurora’s expected reach. The stronger the storm, the farther south the display can extend.
The NOAA storm watch
Space-weather forecasters issue watches when they anticipate a geomagnetic storm, giving skywatchers advance notice of a possible display. Those forecasts draw on observations of the sun and on measurements of the solar wind streaming toward Earth, which allow analysts to estimate both the timing and the likely strength of a storm.
Because the aurora depends on conditions that can shift quickly, such forecasts come with real uncertainty. A storm can arrive earlier or later than predicted and can prove stronger or weaker than expected, so the potential reach into the northern-tier states is a possibility rather than a guarantee. Much of the fine detail becomes clear only in the final stretch of the particles’ journey, when spacecraft positioned upstream measure the solar wind roughly an hour before it reaches the planet.
The source on the sun
Displays that reach far south usually trace back to a specific disturbance on the sun, most often an eruption that hurls a cloud of charged particles into space. When such a cloud is aimed toward Earth, it can take a day or more to cross the distance, and its arrival is what compresses and disturbs the planet’s magnetic field to produce a storm.
Not every eruption is aimed at Earth, and a cloud that leaves at an angle may deliver only a glancing blow or miss entirely. That geometry is part of why forecasts remain probabilistic: analysts must judge not only whether an eruption occurred but whether its trajectory and internal magnetic orientation will couple efficiently with Earth’s field once it arrives. The orientation of the cloud’s embedded magnetic field is especially decisive, because a field pointing opposite to Earth’s links up far more effectively and can turn an otherwise ordinary arrival into a strong storm. That crucial detail usually cannot be measured until the cloud sweeps past monitoring spacecraft stationed upstream, which is why even a well-observed eruption can produce a display stronger or weaker than expected.
How the storm scale works
Space-weather agencies rate geomagnetic storms on a scale running from minor to extreme. The rating reflects how disturbed the planet’s magnetic field is expected to become, and it offers a rough guide to how far south the aurora might be seen and whether technical systems could be affected.
Stronger storms carry effects beyond a pretty sky. Significant geomagnetic activity can interfere with radio communications, degrade satellite navigation signals and, in the most severe cases, stress electrical grids. Minor to moderate storms, the kind that most often drive an aurora into the northern states, typically produce little more than a memorable show. The rare extreme events are a different matter, and history records instances where powerful geomagnetic storms induced currents strong enough to damage transformers and disrupt communications across continents. Operators of power grids and satellite fleets monitor the same forecasts as skywatchers, taking protective steps when a severe storm is expected, though the modest activity behind most low-latitude auroras rarely calls for such measures.
Where and when to look
Seeing the aurora at lower latitudes depends heavily on local conditions. A clear sky and an unobstructed view toward the northern horizon matter, as does getting away from city lights, whose glow can wash out a faint display that would be obvious from darker country.
Timing tends to favor the hours around midnight, when the sky is darkest and geomagnetic activity often peaks, though a strong storm can produce visible color earlier or later. Even when the lights are too faint for the eye, long-exposure cameras can sometimes capture color that the unaided eye misses, since a camera can gather light over several seconds that the eye takes in only for an instant.
Why solar activity is elevated
Displays like this have grown more common as the sun runs through the more active phase of its roughly 11-year cycle. During that stretch, the sun produces more of the eruptions and streams of charged particles that drive geomagnetic storms, raising the frequency of aurora sightings at unusually low latitudes.
For skywatchers across the northern United States, the practical takeaway is to watch the forecasts and be ready to head somewhere dark on short notice. The predicted reach as far south as New York and Idaho would put the display within view of far more people than usual, provided the storm and the weather cooperate.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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