Maps: Will Pennsylvania see northern lights after increased solar activity?

(NEXSTAR) — Skywatchers in the northern U.S. could get another glimpse of the northern lights this week, marking yet another auroral opportunity this month .

NOAA’s Space Weather Prediction Center (SWPC) issued a geomagnetic storm watch Monday after an active weekend of space weather.

Late Sunday, the SWPC noted that a strong solar flare, reaching X1.5 strength, had been observed and had the potential to impact Earth. While not as strong as the X5 flare reported earlier this year, it was one of the strongest in 2024.

Solar flares are classified based on their strength, much like earthquakes, according to NASA . The scale ranges from B-class on the lowest end to C-class, then M-class, and finally, X-class. Each letter represents a ten-fold increase in energy output, and there is a scale of 1 to 9 in each class, except for X-class. X-class flares can exceed 9, with the largest-ever recorded being an X45 that occurred in 2003.

NASA shared the below photo of the solar flare, which is the bright spot in the center of the photo.

That flare, in addition to others and filament eruptions, was associated with coronal mass ejections (CMEs), according to SWPC. Now, several of those CMEs are expected to hit Earth , increasing geomagnetic activity — and our chances of seeing the aurora — over the next few days.

CMEs, like those expected to reach us this week, spark the northern lights. When the plasma and magnetic material that is hurled from the sun by CMEs collide with Earth’s magnetic field, they shoot particles toward the North and South Poles. As those particles interact with gases in the atmosphere, they create excess energy that appears as bursts of light, better known as the aurora.

The stronger the geomagnetic storm (the term used to describe the impacts of the aforementioned solar activity), the further south the northern lights will be visible in the U.S.

Like tornadoes and hurricanes, geomagnetic storms are measured using a 5-point scale. At the lowest end is G1, which is considered minor but strong enough to make the northern lights visible into the northern U.S., like Maine and Michigan’s Upper Peninsula. A G5 storm, described as extreme, could send the northern lights as far south as Florida and southern Texas.

As of Monday morning, the SWPC said any CMEs that reach Earth on Monday could be G1 strength, but “the brunt of the activity” is likely to come on Tuesday. These CMEs could reach G2 or G3 levels.

Monday’s CMEs could bring the aurora into the northern U.S., according to SWPC’s forecast , seen below.

Those with the best chances of seeing the aurora are those in red on the map below. That’s primarily Alaska and Canada for Monday, as well as the very northern portions of Montana, North Dakota, and Minnesota. Those shaded in green — which includes parts of Washington, Idaho, Wyoming, South Dakota, Minnesota, Wisconsin, Michigan, and Maine — also have the chance, albeit low, of catching the aurora.

Those around the red view line on the map below could still see the northern lights shimmer on the northern horizon. For Monday’s forecast, that includes Oregon, Nebraska, Iowa, Missouri, Illinois, Indiana, Ohio, Pennsylvania, New York, Massachusetts, Vermont, and New Hampshire.

Those states may, however, miss out on seeing the northern lights on Tuesday.

As of Monday, the SWPC is predicting that less of the U.S. will have a chance to see the northern lights. Forecasting space weather can be difficult, though, which means this forecast could change before Tuesday night.

With the exception of Alaska, there are no states shaded red for Tuesday’s forecast, which you can see below. States shaded in green or near the view line include Washington, Oregon, Idaho, Montana, Wyoming, North Dakota, South Dakota, Nebraska, Iowa, Minnesota, Wisconsin, Illinois, Michigan, New York, Vermont, New Hampshire, and Maine.

Because it “takes time for CMEs to progress over and past Earth,” the SWPC said we could see geomagnetic impacts into Wednesday as well.

Additional solar flares reaching M-class are also expected this week, with a small potential for X-class flares.

There have already been a handful of strong geomagnetic storms (and with them, bouts of auroral activity) this year, including some that brought the northern lights to Florida and Hawaii. While these types of storms are difficult to forecast, experts say there’s a good chance we’ll experience more in the coming year.

The sun is currently going through a solar cycle, an 11-year period in which it flips its poles. As it reaches the peak of the cycle, the sun also becomes far more active.

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The best part? It doesn’t seem that we’ve reached the peak of Solar Cycle 25 .

We may not reach solar maximum for a few months yet, Mark Miesch , a researcher with NOAA’s Space Weather Prediction Center, tells Nexstar. He also notes that more strong solar storms are expected through the rest of this year, throughout 2025, and potentially even into 2026.

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