Sunspots AR1791And AR1793 Pose A Threat For M-Class Flares

Both AR1791 and AR1793 pose a risk for M-class flares over the next 24 hours. AR1791 is central on the Sun disc and any flare would be Earth directed. AR1793 which is the larger of the two is still on the north-eastern limb of the Sun but will move across over the next day or two.

NOAA estimates the chance of an M-class flare at 25% over the next 24 hours and of an X-class at 0.1% over the same time period.

Considering we are close to the solar maximum of cycle 24, today’s sunspot count of 61 is low. If you take into account the International sunspot number used by most of the world is 35% lower than the Boulder number NASA and NOAA use, the figure is considerably lower still.

This difference comes due to the way the sunspot numbers are counted. NASA class a cluster of sunspots as a group and therefore count it as 10 spots when there may actually only be 7 and therefore the Boulder number is always higher than the International number.

NOAA is also forecasting a geomagnetic storm when the solar wind hits the Earth’s magnetic field. This is currently estimated at 25%, rising to 50% tomorrow and very likely higher than that as the estimates get more accurate nearer the event.