What do Kp numbers mean? Supposed To Be 5 Tonight

First I got this Tweet from AuroraNotify

Kp 5 forecast tonight, looking good!!! https://t.co/ADMTUxALm9 pic.twitter.com/5bKPH8m4rX

— AuroraNotify (@AuroraNotify) September 28, 2016

But I really didn't know what Kp 5 meant.  So I googled and got to Aurora Service:

The Kp number is a system of measuring aurora strength. It goes from 0 to 9 (0 being very weak, 9 being a major geomagnetic storm with strong auroras visible). So when your looking at the aurora forecast page, you want to see high Kp numbers. The higher the better. Anything above (and including) Kp5 is classed as a geomagnetic storm.

I haven't gone outside yet to check the clouds.  The last few times there were aurora notices, it was cloudy.  But it was pretty clear out late this afternoon.  So I'm going out to check.

I did go out and check about an hour ago.  It was dark enough to see a few stars, so it's clear enough.  But no lights.  Then I finished kneading a bread, made some phone calls, went through some old paperwork (AHRGGGGGGG!!), and now I'm back.

Here's a screenshot of the current map on Aurora Services.

From Aurora Services

So it should be a Kp 5 in (now) less than 18 minutes.  I'll go check again.

There are stars out.  I haven't been out looking at stars for a while now.  It's still not dark dark, and I didn't see any northern lights.  I'll post this now and update it later if I see anything.  It didn't feel cold at all without a coat, but when I checked it was 42˚F (5.5˚C), but there's absolutely no wind.