BOULDER, Colo. — Satellite-based communications systems may be affected by a spectacular sun flare which erupted Tuesday and is headed straight for Earth, reports the U.S. National Oceanic and Atmospheric Administration (NOAA).

NOAA forecasters expect the fast moving blast from the sun to reach the Earth’s magnetic field on Wednesday at about midday.

There was a solar flare last week as well but it did not directly impact Earth and did not affect communications, as was predicted then. This one, however, is headed straight for us, say scientists. While people are safe, satellites are not, from the radiation headed this way at 1.6 million km/h.

NOAA space weather forecasters categorized the flare, which occurred yesterday morning, as an X-17 with a full Coronal Mass Ejection or CME. The region of the sun producing this flare is 13 times larger than Earth. Forecasters say that the flare “caused a strong S-3 radiation event, on a scale of 1 to 5 on the NOAA weather scales, and a severe R-4 radio blackout. Radiation storms can affect satellites and cause high frequency communication problems. An R-4 storm can affect high frequency radio blackouts for several hours on the sunlit side of the Earth.

The flare is expected to produce a severe G-4 geomagnetic storm with possible periods of extreme G-5 storming. The solar radiation storm is also expected to continue at strong levels for the next few days.

The Aurora Borealis or Northern Lights may be visible as far south as the northern tier of the U.S. because of it.

“This storm has a lot of similarities to the Bastille Day storm that occurred in July of 2000,” said NOAA forecaster Bill Murtagh. That storm was also located near the center of the sun, and the associated coronal mass ejection also reached Earth very quickly. “The Bastille Day storm produced considerable disruption to both ground and space high-tech systems,” Murtagh said.

NOAA forecasters said the probability of yet another major flare occurring is high, and additional geomagnetic and radiation storms are likely.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation’s coastal and marine resources.