Philly may get another chance to see the elusive northern lights Thursday night

For the second time in a a week, NOAA’s Space Weather Prediction Center is saying it is at least possible that on Thursday night the elusive northern lights may at long last become visible over the Philadelphia region.

The Space Center on Wednesday issued a “severe” geomagnetic storm watch for Thursday — with an outside chance that it would reach the “extreme” level, which could affect power grids and electrify the night sky with undulating curtains of lights this far south.

The center’s scientists said at a briefing Wednesday that the storm, which was ejected from the sun about 10 p.m. Tuesday, was traveling about 2.5 million mph. It was expected to arrive as a “shock front” Thursday “morning to midday,” said center project manager Bryan R. Brasher.

But this is not a supermarket panic-run situation.

No decision would be made on a “warning” until the storm got within satellite-detection range, about a million miles away, and the center said it also was unclear what effects the storm would have, although it could have some impacts on the nation’s power networks and telecommunications.

Given the the continuing recovery from Hurricane Helene, and the threat of cataclysmic damage from Hurricane Milton, space weather officials said they wanted to give FEMA and others as much of a heads-up as possible.

“We don’t know yet what this storm will bring us,” said Shawn Dahl, the center’s service coordinator.

As for the potential of seeing the northern lights around Philadelphia, it’s in play, said Brasher. But a certain skepticism based on recent experiences would be understandable.

As was the case last week, a potent solar storm — commonly called a sunspot — ejected massive quantities of charged particles and magnetic fields that have been streaming toward Earth. Under certain circumstances, the solar material from the so-called coronal mass ejection interacts with the Earth’s magnetosphere to turn on the aurora borealis.

This storm, the scientists said, may turn out be stronger than its predecessor, and may be a G4, or “major” geomagnetic scale, and possibly the a G5, which is at the top of the scale.

A G4 storm in May resulted in the lights being visible all the way to Florida. That is not expected to happen with this one, but if the opportunity is evident over the Philadelphia region, this time around the skies should be clear.

Solar storms have been erupting more frequently lately because the sun has approaching — or possibly has reached — the peak of an 11-year sunspot cycle that began in 2019.

“The sun has been quite active,” said Brasher, more active than had been forecast. The center scientists also said it’s possible that the peak won’t occur until early next year and that heightened sunspot activity could lap into 2026.

They said it was unclear if the coming storm would have any effect on hurricane-recovery efforts by interfering with the power grid or communications system. Center scientist Rob Steenburgh said that Florida’s low latitude would argue against that happening.

Brasher, however, said that NOAA thought it “prudent” to raise cautionary flags.

As for when the lights might be visible, “There’s uncertainty around the arrival time,” Steenburgh said.

Brasher said the most-likely viewing opportunities would be from about 9 p.m. Thursday until 2 or 3 a.m. Friday.

They can appear without notice, vanish quickly, then reappear.

Brasher recommends signing up for alerts from the space weather center.

The center also posts three-day outlooks for solar storms and a corresponding index that’s an indicator of storm intensity and a handy number for tracking aurora potential, along with a chart for monitoring the behavior of the index in three-hour intervals.

Should that index reach 8, Philly could be in play.

You can follow the space weather center on X or Facebook, and the Aurora Dashboard offers real-time predictions.

And it’s a safe bet if the northern lights show up anywhere around here, social media will light up also.