By Jason Samenow

Update, 9:53 p.m.: NASA has responded to questions about its forecast and differences with NOAA. Scroll down to the bottom of this post. Meanwhile, NOAA has produced an excellent video about this event – click here to view.

From 12:31 p.m.: A wave of plasma stoked by an X-class solar flare, the most intense type, is headed towards Earth. This blast of charged particles, known as a coronal mass ejection (CME), is forecast to ignite a geomagnetic storm on Earth over the weekend. NOAA predicts it will be minor, maybe moderate. NASA says it will be moderate to severe.

I ask: which intensity will it be and why aren’t these two science agencies on the same page?

The intensity of the inbound CME matters.

If NOAA’s right, and the ensuing geomagnetic storm is minor, it’s no big deal. It means the high latitudes could be treated to some brilliant auroras over the weekend with few, if any, negative effects on earth-orbiting satellites or the power grid.

On the other hand, if NASA’s right, and the geomagnetic storm is strong to severe, Earth-orbiting satellites could get disoriented and the electrical grid, according to NOAA, could experience “widespread voltage control problems” among other issues. Aurora could be seen as far south as Alabama and northern California.

Video of Thursday’s X-class solar flare courtesy NASA’s Solar Dynamics Laboratory

NOAA and NASA’s predictions about the CME also differ on timing. Last night, NOAA was forecasting a 1 a.m. Saturday arrival of the CME while NASA projected a 6:20 a.m arrival. NOAA has since revised its estimate to 9:00 a.m. NASA tweaked its estimate to 5:17 a.m.

The differences in these predictions raise the question why two government agencies aren’t coordinating and issuing one clear, consistent forecast along with estimates of the uncertainty.

Consider this scenario: A hurricane is approaching the East Coast. What if one U.S. government agency predicted the storm would make landfall as a category 1 to maybe category 2 storm, at worst, while another agency forecast the storm to reach the category 2, 3 or even 4 level? Imagine the widespread confusion that would ensue. How would anyone know if and how to prepare?

There’s a reason the National Hurricane Center closely works with local National Weather Service offices to coordinate hurricane and tropical storm information.

This needs to happen with NOAA and NASA and space weather.

The differences in the geomagnetic storm forecasts for the weekend probably reflect different roles and responsibilities in space weather at the two agencies. NOAA is the nation’s official source of alerts, watches and warnings about space weather and its impacts. NASA’s primary motivation for space weather forecasting is more specialized for “addressing the space weather needs of NASA’s robotic missions”.

Based on these different functions, it would appear NOAA’s information should be considered the most authorative and credible for impacts on Earth and NASA the go-to source for spacecraft. But while NOAA may well be the “official” source of information for our planet, the public and media take what NASA says seriously and NASA’s issuing Earth-based forecasts.

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