The northern lights streak through the sky over a horse barn in Mercer, Maine on May 10, 2024. … [+]
Getty ImagesA promising Northern Lights forecast means that aurora borealis may be visible in the U.S. this Tuesday and Wednesday—July 30 and 31—after Earth-directed solar storms created what scientists call a “cannibal CME.”
A G3-rated geomagnetic storm is being predicted, which is relatively rare, though not as strong or likely to be visible as far south as May 10’s extreme G5 geomagnetic storm that caused displays of aurora worldwide.
Also known as the aurora borealis, the Northern Lights are caused by the solar wind, a stream of charged particles from the sun. As they strike Earth’s magnetic field, they accelerate down its magnetic field lines at the north and south poles to create ovals of green and red. If the solar wind is intense, those ovals stretch further south—and can be visible in the U.S. and Europe.
When To See The Northern Lights
A three-day space weather forecast issued by NOAA’s Space Weather Prediction Center has a G3-grade geomagnetic storm striking Earth on Tuesday, with G2 conditions predicted on either side.
Displays of Northern Lights could be seen over northern and upper Midwest U.S. states, from New York to Idaho, on Tuesday evening and possibly Wednesday. “Periods of G1 (Minor) geomagnetic storms are likely on 29-31 Jul, periods of G2 (Moderate) storms are likely on 30-31 Jul, and periods of G3 (Strong) storming are likely on 30 Jul,” reads the forecast. “Multiple CMEs from 27-28 Jul are expected to arrive late 29-31 Jul.”
Why The Northern Lights Are Likely
A CME is a coronal mass ejection. It’s a cloud of magnetic fields and charged particles from the sun that streams into space at up to 1,900 miles (3,000 kilometers) per second. However, they travel at different speeds, thus arriving at Earth at different times—typically a few days later. CMEs usually occur in the wake of solar flares, which travel at light speed to Earth, often causing radio blackouts, but which do not result in aurora.
SpaceWeather.com reports that several M-class solar flares over the weekend were followed by CMEs, two of which merged to form a “cannibal CME,” and that a “wagon train” of CMEs is on its way behind it.
That could mean displays of aurora from the “cannibal CME” are fueled by the CMEs arriving later. “The storm clouds should reach Earth no later than July 31st, potentially intensifying any geomagnetic storm already underway,” states SpaceWeather.com.
A strong solar flare was observed on the sun on July 29, 2024.
NOAA SWPCWhere The Northern Lights Could Be Visible
G2 storms can generally be seen as far south as New York and Idaho; for G3, it’s Illinois and Oregon; for G4, it’s Alabama and northern California. Aurora hunters are advised to check this page for North America’s latest “aurora view line”. According to the SWPC, the viewline represents the southernmost locations from which you may see the aurora on the northern horizon.
However, some experts warn that predictions of the exact timings of displays of the Northern Lights should be taken with a pinch of salt. “Please take timing very lightly,” said Sara Housseal, a space weather forecaster, on X. “With numerous CMEs in play, it is extremely difficult (if not impossible) to determine specifics with timing … the forecast is NOT intended to be taken verbatim for things like aurora.” She advises ignoring the specific predictions of exactly when aurora could result, instead focusing just on the days in question—July 30 and 31.
Another space weather forecaster, Dr. Tamitha Skov, stated on X that “Space weather forecasts are still in their infancy. In complex storm series like this one, the margin of error can be on the order of +/-24 hours.”
How Best To See The Northern Lights
Displays of the Northern Lights are currently more frequent than typical because the sun is entering the “solar maximum” phase of its 11-year cycle. Those in North America might be able to catch a glimpse of the Northern Lights as a faint glow on the northern horizon. To see them clearly, it’s best to be in a place far from city lights (check the Light Pollution Map).
However, to have the greatest chance of seeing the phenomenon, consider planning a trip to areas near the Arctic Circle, like Alaska, northern Canada, or northern Scandinavia (Norway, Finland, Sweden, and Iceland) in the next two to three years.
Pick up my books Stargazing in 2024, A Stargazing Program For Beginners, and When Is The Next Eclipse?
Wishing you clear skies and wide eyes.
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