4.00 Kp index 27 ap index
Minor Geomagnetic Storm
PLANETARY INDICES
High Latitude Aurora Viewing Possible
Est. daily 17 Ap index
Minor Geomagnetic Storm
RADIO AURORA ACTIVE
High Latitude Radio Aurora
50-144 MHz Possible
The higher the 3-hourly Kp index (0-9) the greater the chance of seeing the Aurora Borealis. The data are collected from ground-based magnetometers at 13 mid-latitude observatories (only 8 in this case). The scale is non-linear.
The ap index (0-400) is the equivalent 3-hourly range: the amplitude on a linear scale.
This Ap 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.