KP 7+ but not visible from Stockholm?

[Guest LayarKom]

I have been waiting for aurora at around midnight between 20-21 Dec in Stockholm. KP index is around 7 (or maybe 8 in prediction) and the magnetic field direction is south. Every data here looks very good. But why there is only very slight greenish line on the sky? I believe that KP index on Oct 8 2015 was lower than today's, but at that time we can see a very clear aurora, even from heavily-light-polluted Stockholm's city central. Do I miss something? Just curious

Thanks!

[Marcel de Bont]

Maybe you saw a more quiet period? The Kp-index is the highest observed value over a 3 hour period so you might have been watching when the aurora was more quiet. Should be harder to see from a large city like Stockholm. Despite the cloud cover which was a problem in large parts of the country, I did see fantastic images from Sweden.

[Guest Niclas Poul Krog]

2 hours ago, LayarKom said:

I have been waiting for aurora at around midnight between 20-21 Dec in Stockholm. KP index is around 7 (or maybe 8 in prediction) and the magnetic field direction is south. Every data here looks very good. But why there is only very slight greenish line on the sky? I believe that KP index on Oct 8 2015 was lower than today's, but at that time we can see a very clear aurora, even from heavily-light-polluted Stockholm's city central. Do I miss something? Just curious

Thanks!

You should have sen it
Join the group "Norrsken"
There are and pics  and observation reports  contionusly uppdated

.

[Guest Carl Bergstrand]

5 hours ago, Niclas Poul Krog said:

You should have sen it
Join the group "Norrsken"
There are and pics  and observation reports  contionusly uppdated

.

Marcel and I are friends and continuously communicate with each other regarding solar storms and the northern (and southern) lights. The Norrsken-page / community and Spaceweatherlive is in "a relationship", acting as a compliment (or rebels) to other Aurora-pages, mainly mainstream forwarding NOAA-forecasts. We spend a great deal of time thinking, instead of letting the modells do the work (no offense, NOAA). The question then: 
As Marcel posted, the Kp-index isn´t really a great tool. It´s a guide, but often a false one. The 3-hour-index is often slow, and not accurate. I´ve been experiencing strong auroras from Gotland, Sweden during Kp 3+, and seen zero activity (even with 30s exposures) during a "MASSIVE G3-STORMING"... What happened yesterday is, from my experience two things. If you look at the page you´ll see great images from South of Stockholm around 17.20 (local). The density and the speed was at greater levels during that period of time. If the speed and the density factor had been at higher levels, the show most certain had been more continual and with more powerful outburst of auroras. As we wrote, I think at least two times: Be patient. The aurora will flicker and outbursts will almost for certain be followed by calmer skies, to be followed by more "explosions in the sky". This is very common, and something we as chasers will have to accept. The magnetism behind all of this is complex, and the ingredients of the aurora is dynamic, with so many variables and factors, Bz being one of the most important of them. 

Anyway, nice pics you posted. Love the 1s ISO300-exposure. Take care! 
// Calle 

 

[Guest auroraville]

We had the same discussion on this side of the big pond and more or less came to the same conclusion- it was the lack of speed which crippled this show from what it could have been. All the other numbers looked excellent for much of the storm.