What's kind of interesting here is that NOAA, who does the official space weather forecast, and NASA are quite at odds with each other over the expected impacts of the CME due on Saturday. As the Washington Post reports (at that link):
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.Personally, as someone who observes this sort of stuff and its effects, I'm going with NOAA: minor, maybe moderate. Auroras visible south of Michigan, say, but probably not into the deep south. It seems to take an X6 flare to get auroras visible in Dixie, and an epic flare to get them down here into Florida. But why should NASA and NOAA differ so much? It's not like NASA should have data that they hoard and don't pass on to NOAA. Quoting again:
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.In terms of effects, if you go with NOAA's predictions, you're not likely to see any effects other than some pretty lights in the sky, if you're out in a really dark spot; if you're a ham, HF propagation might be disturbed, giving higher noise levels or shutting down HF. (Some of this happened yesterday). If NASA's predictions are right, the auroras will come farther south, radio will be disturbed more, and - this might be important - satellites may need to be re-oriented or shut down. Maybe the reason NASA is going for the worst possible prediction is to protect satellite operators better. After all, NASA doesn't loose any revenue if satellite operators shut down when they really didn't need to.
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?
I need to point out that space weather isn't as well understood as earthly weather, and predicting rain messes us up often enough. I'm not calling them stupid. I just think they should be working a little closer together on this.
For the record, NASA is saying:
“Simulations indicate that the leading edge of the CME will reach Earth at about 2012-07-14T09:17Z (plus minus 7 hours). The roughly estimated expected range of the Kp maximum (Kp is a measure of geomagnetic disturbance levels ranging 0 - 9) is 6-8 (moderate to severe).” (note: that's 5:17 AM EDT +/-7 hours)and NOAA said:
"The latest model run now indicates the CME associated with yesterday’s R3 (Strong) Radio Blackout event will impact the earth’s magnetic field around 9:00 a.m. EDT (1300 UTC) on Saturday, July 14. SWPC is forecasting category G1 (Minor) Geomagnetic Storm activity then, with a chance of G2 (Moderate) levels at times through July 15."To reiterate, I bet with NOAA on this one. No damage to the grid or any of the dire scenarios that get talked about.