4.00 Kp - Index 27 ap index

Minor Geomagnetic Storm

Kp - Planetary Index

High Latitude Aurora Viewing Possible

The higher the Kp - Index (0-9) the greater the chance of seeing the Aurora Borealis. The three-hourly K index data is collected from ground-based magnetometers at 13 mid-latitude observatories. The scale is non-linear.
The ap index (0-400) is the equivalent three-hourly range or amplitude on a linear scale.

This A - Index estimate is the rolling average of the last eight ap indices: the true Ap index is the same average for the UT day. High Kp, ap & Ap indices (caused by strong solar activity) may indicate enhanced VHF radio communication (28-433 MHz) at a range of 1000 miles or more in mid- to high latitudes: the radio-aurora.