Daily forecast explanation

Solar activity. Transient pertubations of the solar atmosphere as measured by enhanced x-ray emission (see x-ray flare class), typically associated with flares. Five standard terms are used to describe the activity observed or expected within a 24-h period:

(1) Very low - x-ray events less C-class
(2) Low - C-class x-ray events
(3) Moderate - isolated (1 to 4) M-class x-ray events
(4) High - several (5 or more) M-class x-ray events, or (1 to 4) M5 or greater x-ray events
(5) Very high - several (5 or more) M5 or greater x-ray events

**X-ray flare class**
Class	Peak (W/m²) between 1 and 8 Angstroms
B	I < 10^-6
C	10^-6 < = I < 10^-5
M	10^-5 < = I < 10^-4
X	I > = 10^-4