Washington, D.C. – A rare G4 (Severe) geomagnetic storm, in effect for Jan. 20, is expected to reach Earth just as a powerful Arctic air mass pushes into the Mid-Atlantic, increasing scrutiny on power and critical infrastructure as temperatures drop sharply across the region.
According to the NOAA Space Weather Prediction Center, a coronal mass ejection, or CME, launched from the Sun late last week is forecast to arrive late Sunday into Monday. G4 geomagnetic storms are uncommon and can disrupt power transmission systems, satellite operations, GPS accuracy, and some radio communications, particularly over large electrical networks.
The geomagnetic storm watch includes Pennsylvania, New Jersey, Delaware, Maryland, the District of Columbia, Virginia, and West Virginia. While the Mid-Atlantic is less exposed than northern New England, officials note that long-distance transmission lines and dense population centers increase the importance of grid stability during periods of high demand.
Forecasters emphasize that widespread power outages are not expected. However, the timing coincides with an Arctic outbreak forecast to bring single-digit temperatures and dangerous wind chills, increasing electricity demand for heating and reducing the system’s margin for error if equipment issues arise.
For most residents, the solar storm itself will not be noticeable. Experts explain that the concern is not the storm alone, but the overlap with extreme cold, when power systems are already under stress. Utilities typically increase monitoring during geomagnetic events and may take precautionary actions to protect sensitive equipment.
Residents are encouraged to follow standard cold-weather preparedness guidance, including keeping electronic devices charged and preparing for winter travel. Cell phone service and internet connectivity are expected to remain largely unaffected.
As a secondary effect, auroras may be visible farther south than usual, potentially reaching parts of Pennsylvania, New Jersey, and inland Mid-Atlantic locations if storm conditions intensify.
Geomagnetic activity may linger at lower levels into Tuesday as the coldest air settles across the eastern United States.
