NOAA’s Space Weather Prediction Center has placed a G2 (Moderate) geomagnetic storm watch in effect for tonight, May 15 into May 16. The trigger is a fast-moving solar wind stream pouring out of a large coronal hole, an opening in the Sun’s magnetic field, that has now collided with Earth’s magnetosphere. For millions of Americans from New York and Wisconsin up through Maine and Montana, the storm opens a rare window to catch the aurora borealis without booking a flight to Iceland.
Peak Window: 11 PM to 2 AM EDT, New Moon Working in Your Favor
The storm is powered by what scientists call a corotating interaction region (CIR), a dense wall of compressed plasma that builds up where faster-moving solar wind catches up with slower wind released earlier in the Sun’s rotation. Unlike a sudden coronal mass ejection, CIRs develop gradually and give forecasters time to prepare. NOAA spotted this one as early as May 13, giving satellite operators and power grid managers a few days of advance warning.
Storm activity is expected to peak between 3:00 AM and 6:00 AM UTC on May 16, which works out to approximately 11 PM to 2 AM EDT tonight. After that, lighter G1 (Minor) conditions are likely to stick around through May 16 and 17 as the solar wind slowly settles. A new moon this weekend is welcome timing since there’s no moonlight washing out the sky, which is one of the biggest obstacles to spotting aurora at lower latitudes.
Northern lights could be visible as far south as New York, Wisconsin, Minnesota, Michigan, and Maine. NOAA’s Aurora Dashboard and its Planetary K-index tracker, which refreshes every three minutes, are the best tools for checking conditions in real time. When the Kp reading hits 6 or above, G2 conditions are confirmed and the aurora is active.
For the best shot at seeing it: get at least 30 to 40 minutes away from city light pollution, face north, and try your phone camera on a long exposure of three to five seconds. Camera sensors pick up the green and red wavelengths of aurora that the naked eye often misses entirely. Cloud cover may cause problems across the Midwest and Great Lakes tonight, but the northern Great Plains and New England are forecast for clearer skies.
What a G2 Storm Actually Does to Satellites and Power Grids
A G2 sits at the midpoint of NOAA’s five-level storm scale. It is not catastrophic, but the effects on infrastructure are real. High-frequency radio communications at high latitudes take a hit, which is a direct problem for transpolar flight routes between North America and Asia. Airlines operating over Arctic airspace may need to reroute to lower latitudes to maintain radio contact.
Satellite operators face two specific concerns during a G2 event. First, magnetometer interference can cause brief errors in spacecraft orientation systems. Second, geomagnetic activity heats and expands the upper atmosphere, adding drag to objects in low Earth orbit. For operators of large constellations like SpaceX’s Starlink and OneWeb, that means firing thrusters more often to hold orbital altitude, which burns through limited fuel reserves and shortens how long each satellite can operate.
This is not a hypothetical risk. In February 2022, a G1-to-G2 storm hit just one day after SpaceX launched a batch of 49 new Starlink satellites. Up to 40 of them were lost because the elevated atmospheric drag, which SpaceX reported was running up to 50 percent above normal, prevented the satellites from climbing to their operational orbit. Tonight’s conditions are milder and established satellites at higher altitudes are far less exposed than that freshly launched batch was, but the incident shows how even moderate space weather can translate into hundreds of millions in lost hardware.
On the ground, geomagnetically induced currents (GICs) are the main concern. These are slow electrical currents that geomagnetic activity injects into long power transmission lines, causing transformer overheating, harmonic distortion, and gradual wear on insulation. A single G2 rarely causes widespread outages, but repeated moderate storms chip away at transformer lifespans over time. U.S. transmission operators are now required under NERC standard TPL-007-1 to assess their GIC exposure, and many utilities in northern states have already fitted protective blocking devices.
A NASA Instrument Launching Tonight Was Built Specifically for Storms Like This
Tonight’s storm coincides with SpaceX’s third attempt to launch the CRS-34 resupply mission to the International Space Station, scheduled for 6:05 PM EDT from Cape Canaveral. Two previous launch attempts on May 12 and May 13 were each called off due to weather at the pad.
One of the payloads aboard CRS-34 is STORIE (Storm Time O+ Ring Current Imaging Evolution), a joint NASA and U.S. Space Force instrument purpose-built to image Earth’s ring current, the donut-shaped band of energetic particles surrounding the planet that intensifies during geomagnetic storms. When the ring current swells, it drives the surface magnetic disturbances responsible for GICs in power lines and errors in GPS and compass navigation.
Once the ISS robotic arm mounts STORIE to the exterior of the Columbus module a few days after docking, it will build a full picture of the ring current roughly every 90 minutes as the station orbits. Its six-month science mission centers on a question that still doesn’t have a clean answer: are the energetic particles fueling the ring current coming mainly from the solar wind, or from Earth’s own upper atmosphere? Oxygen ions are the key diagnostic, since oxygen in the ring current points to an atmospheric origin rather than a solar one. Better answers will sharpen the accuracy of space weather forecasts, giving power grid operators and satellite teams better data the next time a storm rolls in.
Solar Cycle 25 Outperformed Every Forecast, and Activity Is Still Elevated
Nights like this one are going to keep happening. Solar Cycle 25, the roughly 11-year rhythm of solar activity that we are currently in, has significantly outpaced its original projections. In 2019, a joint NOAA, NASA, and International Space Environment Services panel forecast the cycle would peak at a smoothed sunspot number of 115 around July 2025. The actual peak, recorded in October 2024, came in at 161, around 40 percent higher than predicted.
Solar activity has stayed elevated well into the cycle’s declining phase. Early 2026 has seen sustained X-class flare activity, and CIR-driven storm events are expected to keep occurring at elevated frequency through at least mid-2027. Space weather researchers flag that 18-month window as a period of heightened risk for satellite operations and high-latitude power infrastructure, not a single outlier event.
For aurora hunters, that also means tonight is not the last opportunity this year, not even close. Signing up for free email alerts from NOAA’s Space Weather Prediction Center puts the next storm warning in your inbox before it arrives.
