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Merged Here comes another Aurora Borealis

jj said:
Annoyingly, they have built a megachurch about a half mile north of us. Massive sky glow from all their brightly lit torture devices.

Grrr........
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Just cruise on over Novelty Hill and it gets dark again. :D

Here's a link to the magnetic latitude page. Find a city that is close to your latitude and see what the magnetic latitude is. For Seattle it is about 53. Then in the lower left corner you can see what Kp index has to reach to make it worth going outside to check the sky. Again for Seattle we need a Kp of about 6.5. Another indicator is the NOAA POES satellite which monitors the aurora oval. For the aurora to be seen in Seattle we need about a 10. That's as high as the NOAA POES number goes so at lower latitudes one has to use the Kp index.

To see what the current activity is go to this page for the Kp level and this page for the POES activity. There is also this space weather alert page. Don't confuse the K on that page, however, with the Kp on the other. They are not the same. The last link is great because about an hour before the CME gets here, it hits the satellites and will show up as a "sudden impact".
 
Skeptic Ginger said:
Here's a link to the magnetic latitude page. Find a city that is close to your latitude and see what the magnetic latitude is. For Seattle it is about 53. Then in the lower left corner you can see what Kp index has to reach to make it worth going outside to check the sky. Again for Seattle we need a Kp of about 6.5. Another indicator is the NOAA POES satellite which monitors the aurora oval. For the aurora to be seen in Seattle we need about a 10. That's as high as the NOAA POES number goes so at lower latitudes one has to use the Kp index.

To see what the current activity is go to this page for the Kp level and this page for the POES activity. There is also this space weather alert page. Don't confuse the K on that page, however, with the Kp on the other. They are not the same. The last link is great because about an hour before the CME gets here, it hits the satellites and will show up as a "sudden impact".
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Some very good links. I was going to post a few, but you either got the better ones, or duplicates.

Just remember, you don't have to actually be able to see the Auroral curtain. It acts as a reflector for radio signals also. As hams, we used to deliberately bounce VHF signals of it (don't get to do much of that since I moved to AZ, sob) but you can listen for distant FM stations that get fortuitous reflections. In the old days of analog TV we'd listen for the long distant carriers showing the characteristic frequency smearing from Doppler.

Anyway, I have a lovely clear sky, but am way to far south to see this one. Many more coming, I hope!

Clear skys!

V.
 
Any chance you could explain this radio event alert to me, Verde?
Space Weather Message Code: ALTTP2
Serial Number: 746
Issue Time: 2011 Sep 09 0652 UTC

ALERT: Type II Radio Emission
Begin Time: 2011 Sep 09 0618 UTC
Estimated Velocity: 717 km/s
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I'm trying to figure out what caused it since there was only a C class flare prior to it.

There are so many things about solar weather I don't know enough about.
 
Skeptic Ginger said:
Any chance you could explain this radio event alert to me, Verde?I'm trying to figure out what caused it since there was only a C class flare prior to it.

There are so many things about solar weather I don't know enough about.
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The Sun is an active emitter of wide-band electromagnetic energy. We recently had an increase in sunspots, which has a good correlation to the RF solar flux, and hence ambient noise. A big CME will knock the magnetic index up, but only has a short-term effect on radio noise. It may well produce a nice aurora, however. Solar flares are pretty much in the same category, it depends whether it is directed at the Earth.

It can have a major impact on satellite communications, if the bird is aligned with the Sun (from the ground observers point of view). Thus there is a need to issue warnings that may impede the reliability of the path.

I tend to go to this site for solar info:

http://www.solen.info/solar/

The links from there should answer your question.

V.
 
The first impact has arrived and it is morning here. Wherever it is night, there's a Kp of 5 storm currently. I'm hoping that's the M5 flare's CME.

The M5 flare began on 2011/09/06 at 01:35:00 UT.
The next big flare, an X1, was on 2011/09/06 at 22:12:00 UT.

That's ~20.75 hours difference. CMEs from bigger flares travel faster. According to the NOAA alert web page:
Geomagnetic Sudden Impulse
Observed: 2011 Sep 09 1250 UTC

Geomagnetic K-index of 4
Threshold Reached: 2011 Sep 09 1247 UTC
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If the next CME was traveling at the same speed it would get here at ~09:30UT which is ~02:30am PST.


There's definitely a very good chance of high geomagnetic activity tonight. :D
 
Verde said:
The Sun is an active emitter of wide-band electromagnetic energy. We recently had an increase in sunspots, which has a good correlation to the RF solar flux, and hence ambient noise. A big CME will knock the magnetic index up, but only has a short-term effect on radio noise. It may well produce a nice aurora, however. Solar flares are pretty much in the same category, it depends whether it is directed at the Earth.

It can have a major impact on satellite communications, if the bird is aligned with the Sun (from the ground observers point of view). Thus there is a need to issue warnings that may impede the reliability of the path.

I tend to go to this site for solar info:

http://www.solen.info/solar/

The links from there should answer your question.

V.
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That's a great site for looking at the coronal holes. Solar wind pours from the holes. The wind triggers geomagnetic storms, but I've never seen one from the solar wind alone that caused enough activity to be seen here in Bellevue(Seattle). However, the solar wind can add to an incoming CME impact.
 
From Spaceweather today:
GEOMAGNETIC STORM: A polar geomagnetic storm (Kp=5) is in progress following the impact of a CME around 1100 UT on Sept. 9th. This could be the first of several hits from a series of CMEs expected to reach Earth during the weekend. High-latitude sky watchers should be alert for auroras after nightfall. Aurora alerts: text, voice.

Update: Electrical ground currents caused by the storm have been detected in Norway.
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Just as a curiosity side note, I wonder why the time reported differs in the two sources?
 
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If it is dark where you are, the aurora is now at Kp of 7. That would be enough to see it in Seattle if it weren't noon here. :(
 
56N here. 53 deg N corrected from the site you linked. Clear sky to north, big moon to south. Nothing unusual so far. (23:00 my time)
 
Soapy Sam said:
56N here. 53 deg N corrected from the site you linked. Clear sky to north, big moon to south. Nothing unusual so far. (23:00 my time)
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Current conditions updated every three hours shows the Kp dropped below 7 probably around 8 or 9pm your time. You're at about the same geomagnetic latitude as I am. We need a Kp of 7 at a minimum to see much. But keep checking. There are two more bigger CMEs on the way and another M class ejection.

Here's the Northern aurora overview for the last 12 satellite passes.
 
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It clouded over about midnight. Been raining ever since.
I've seen the aurora from Scotland before, but about 200 miles north of here, in winter, in a place with less light pollution.
Best I ever saw was from an aircraft over Greenland.
 
The report is one could see it in WA State. Maybe Tess in B'ham got a glimpse? I was up most of the night and it was apparently not visible from Seattle. From Spaceweather.com
Last night Northern Lights were spotted in the United States as far south as Washington, Michigan, Vermont, Montana, Maine and North Dakota. More geomagnetic activity could be in the offing as one or two more CMEs approach. Stay tuned.
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So I guess I'll try again tonight.
 
Halfcentaur said:
Argh, I flew over Greenland once, but it was during the day. :(
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When we flew to Iceland the aurora was visible out the plane window though it was more green glow without a lot of detail. But there was no activity when we were in Iceland that we got any glimpses of.
 
Nope, I didn't see it. I think there's just too much ambient light at night here in town for that to work out well.

Is it supposed to be visible again tonight? What time-ish? I'm having trouble making sense of the space weather site...
 
tesscaline said:
Nope, I didn't see it. I think there's just too much ambient light at night here in town for that to work out well.

Is it supposed to be visible again tonight? What time-ish? I'm having trouble making sense of the space weather site...
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Well if you think of it like the other weather predictions, it will make more sense. The predictions are not precise so they give you odds instead. Without much practice anyone can make the same 'odds' predictions. When a large CME is headed for Earth, that's about the only time the aurora is visible this far south (or north if you are down under). If you were close to the poles, then CMEs, the solar wind from coronal holes and events I've yet to make sense of can all spark auroras.

Solar flares are monitored by a number of satellites. They only send plasma (CMEs) Earth directed if the flare is about in the middle of the Sun and even then flares can send ejecta laterally. Less often, a lateral flare will be directed toward Earth.

Then there is the problem of judging arrival time. It's one of those give or take 12 hours (sometimes give or take 24 hours) because the speed of the CMEs are not always the same.

Bottom line, the best you can do is check the monitoring sites often when a CME is Earthbound. Activity just picked up a couple hours ago. Wait until dark and check the sites again.
 
Cloudy, unseasonably warm and humid here. My parents are in rural Norway right now, have to check with them.
 
Here's a beautiful image of the aurora from the San Juans. Maybe it wasn't dark enough here. Or maybe it was so fleeting that the near constant checking on my part still missed it. I dunno but it's a bit frustrating knowing I watched diligently and missed it while someone in the San Juans had this gorgeous view.

It's clear now but supposed to be cloudy later. The activity is at level 5. It's still possible an activity increase will occur and be timed right tonight but the probability is not high. Still, I'll be checking the night sky off and on.
 
Skeptic Ginger said:
Here's a beautiful image of the aurora from the San Juans. Maybe it wasn't dark enough here. Or maybe it was so fleeting that the near constant checking on my part still missed it. I dunno but it's a bit frustrating knowing I watched diligently and missed it while someone in the San Juans had this gorgeous view.

It's clear now but supposed to be cloudy later. The activity is at level 5. It's still possible an activity increase will occur and be timed right tonight but the probability is not high. Still, I'll be checking the night sky off and on.
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Whoa. That's spectacular. If only I'd thought to go down to the marina, instead of checking out my balcony... *sigh*

Well, there's due to be more of this over the next little while, right? Hopefully I'll get a glimpse :)
 
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