Tonight could bring a rare treat for skywatchers across the northern United States: the northern lights, courtesy of a solar eruption that happened three days ago on the far side of the sun. NOAA’s Space Weather Prediction Center has issued a G2 (moderate) geomagnetic storm watch for the evening of May 13, with aurora visibility projected as far south as New York, Wisconsin, and Washington state.
The source is a coronal mass ejection, or CME, that launched from active region AR 14436 on May 10, linked to a moderately strong M5.7 solar flare. Because the eruption originated on the sun’s backside, only the outer edge of the plasma cloud is expected to sweep past Earth. That glancing geometry makes the difference between a spectacular light show and a quiet night razor-thin.
What spacecraft captured
Four separate instruments recorded the blast. NASA’s Solar Dynamics Observatory (SDO), the GOES solar ultraviolet imager, SOHO’s LASCO coronagraph, and the STEREO-A spacecraft all logged the event as a partial-halo CME, meaning the expanding cloud of magnetized plasma spread asymmetrically rather than ballooning out in every direction. The official DONKI catalog entry from NASA’s Community Coordinated Modeling Center documents the observations.
STEREO-A proved especially valuable here. Orbiting the sun well away from Earth’s line of sight, it provided a side-angle view that confirmed the eruption’s backside origin and showed one flank of the plasma cloud curving toward Earth’s orbital path. That footage, available through the STEREO science archive, is what allowed forecasters to classify this as a glancing blow rather than a direct hit or a clean miss.
NASA’s WSA-ENLIL+Cone model, the standard tool for tracking CME propagation through the solar wind, places the arrival at Earth during a window on May 13 UTC. NOAA’s forecasters used that model output alongside the multi-spacecraft imagery to issue the G2 watch, judging the disturbance strong enough to push aurora south of the Canadian border. While G2 storms can trigger voltage alarms in high-latitude power systems according to NOAA’s geomagnetic storm scale, widespread infrastructure damage is unlikely at this level.
Why the forecast could shift
A G2 watch is a forecast, not a guarantee, and several factors could push the outcome in either direction.
The biggest unknown is the magnetic field orientation inside the CME itself. Geomagnetic storms intensify when the arriving plasma carries a southward-pointing magnetic field, which merges with Earth’s own field and funnels energy into the upper atmosphere. No instrument can measure that orientation until the leading edge of the cloud reaches the monitoring satellites roughly a million miles from Earth at the L1 Lagrange point. If the field turns out to be mostly northward, the storm could fizzle even if the plasma arrives on schedule.
Timing matters, too. The WSA-ENLIL model produces a single best-estimate run, and individual predictions can miss actual arrival times by six to twelve hours, according to CCMC validation studies. A shift of just a few hours could push the peak interaction into daylight over North America, rendering any aurora invisible to ground observers regardless of storm strength.
There is also the question of what the solar wind looks like between the sun and Earth right now. Coronal holes and high-speed streams can either amplify or dampen an incoming CME depending on how their magnetic fields line up. Forecasters assume average background conditions when detailed measurements are unavailable, and if those assumptions are off, the actual geomagnetic response could land above or below the G2 expectation.
Finally, the source region itself has been rotating farther around the sun’s far side since the eruption. Updated farside magnetograms from the NSO’s GONG network, which use helioseismology to estimate magnetic activity on the sun’s hidden hemisphere, have not been released for the period after May 10. If the active region’s position shifted more than expected, the actual impact corridor could be narrower and arrive later than current models suggest.
How strong the evidence actually is
The eruption itself is not in question. Four spacecraft independently recorded it, and STEREO-A’s off-axis view nailed down the geometry. That a significant blob of solar plasma launched toward Earth’s neighborhood on May 10 is as close to certain as space weather gets.
The arrival timing is reasonably well constrained but not locked in. NOAA’s G2 watch reflects professional judgment that the model guidance, combined with direct observations, justifies a moderate storm alert. G2 storms are strong enough to produce visible aurora at mid-latitudes but fall well short of the kind of extreme events that make headlines for disrupting infrastructure. For comparison, the dramatic aurora displays that reached as far south as Florida and Texas during the May 2024 geomagnetic superstorm were driven by G5-level conditions, far more intense than what is expected tonight.
The wild card is storm intensity. Until real-time solar wind monitors at L1 detect the shock front and measure the magnetic field, the exact strength of the geomagnetic response remains an educated guess. NOAA’s forecast discussion will be updated as new data arrives, and aurora chasers should treat it as the most reliable near-term source.
Where and when to look
If the CME arrives near the predicted window and delivers even a moderately southward magnetic field, observers across the northern tier of the United States and much of southern Canada have a legitimate shot at seeing the northern lights after local nightfall on May 13.
The best odds go to anyone with clear skies, minimal light pollution, and an unobstructed view to the north. During G2-level storms, auroral arcs typically appear as a low, greenish glow hugging the northern horizon at mid-latitudes. During stronger substorm surges, colors can climb higher and occasionally ripple overhead.
A few practical tips for tonight:
- Give your eyes at least 15 to 20 minutes to adjust to the dark. Smartphone screens will wreck your night vision.
- Geomagnetic activity comes in waves. A quiet sky at 10 p.m. does not rule out a burst of color at midnight.
- NOAA’s 30-minute aurora forecast, available on the Space Weather Prediction Center website, updates in near real time and shows the projected aurora oval over North America.
- Smartphone cameras with long-exposure or night modes often pick up auroral color that the naked eye struggles to see, especially at lower latitudes.
A busy sun keeps the door open
Even if tonight’s display underwhelms, the broader outlook for aurora watchers remains encouraging. Solar Cycle 25 has been running well above early predictions, and the sun continues to produce flares and CMEs at an elevated rate heading into mid-2026. NOAA’s monthly sunspot numbers have consistently exceeded the original forecast curve, meaning more geomagnetic storms and more chances for northern lights at unusually low latitudes in the months ahead.
For now, the best move is simple: step outside after dark, look north, and give the sky a chance to surprise you.
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*This article was researched with the help of AI, with human editors creating the final content.
