Energy from a large sunspot ejection from the Sun is headed to Earth, triggering a geomagnetic storm watch for Sunday night through Monday, July 16-17 by the National Oceanic and Atmospheric Administration.
As that geomagnetic energy, known as a coronal mass ejection, hits Earth it likely will trigger the northern lights.
NOAA has predicted a geomagnetic storm of G2 strength, which would be a storm of moderate strength. That leads to a forecast of kP 6 for how far south the northern lights might be seen on Sunday night.
A kP 7 usually is needed to push the viewing opportunities south as far as the Pennsylvania-New York state line.
However, it’s a forecast and the geomagnetic storm could be stronger or weaker when it impacts Earth.
The weather forecast for Sunday night offers a good chance of mostly clear skies, but with the possibility of some rain. If the northern lights do show as far south as Pennsylvania, clear skies will be needed for viewing them.
In addition, the darker the skies the better for viewing.
The NOAA will update its forecast as the geomagnetic energy gets closer to Earth. We’ll provide updates on any significant changes.
The northern lights, also known as the aurora borealis, are the result of collisions between electrically charged particles from the sun and gaseous particles in Earth’s atmosphere. Variations in the color of the lights are due to the different types of gas particles.