Aurora Tracker: Finding The Northern Lights
Short Term (Next Few Hours):
Aurora Alerts For Active To Strong Displays (Kp 4 or higher)
This is a good general forecast for today and the next few days made by the University of Alaska in Fairbanks. Keep in mind this map is an average forecast for local midnight. If a geomagnetic storm is forecasted or is in progress the aurora normally travels further south than what the forecast's predict.
The 27-day outlook provides a rough idea of the Kp index over the next 4 weeks. You have to take this forecast with a grain of salt. The forecast is taking the current state of the sun and comparing it with earth as the sun does a complete rotation. This outlook is most useful for northern latitudes and it seems to better perform in low solar activity and solar minimums. It does not take into account CME's that often lead to geomagnetic storms and affect lower latitudes. If you want to look at previous solar rotations click on the picture below.
The Northern Lights are one of the most incredible wonders of nature. The sun's solar wind bombards the earth and energizes gases that light up like a neon sign once they hit earth's atmosphere. The Mysterious lights shine ribbons and sheets of yellow-green bands of color over the earth continuously but most of the world can't see them because of the earth's magnetic field. This shields all but the top and bottom of the earth from the marvelous aurora most of the time. So the biggest factor on seeing the lights is location!
Areas further north near the aurora oval have the best chance of seeing the northern lights on any given night. It is estimated that if the sky was clear every night in central Arkansas folks could see the northern lights twice a year, the Boundary Waters Canoe Area Wilderness in northern Minnesota could see the lights around 100 nights a year and Fairbanks gets to see the aurora about 240 nights a year assuming every night was clear (would be more if the summer had enough darkness in Alaska) So each location in the United States can see the northern lights if the conditions are right. See #3 to find out what your location's solar activity needs to be in order to see the lights.
Regardless of location and solar activity you need a clear or mostly clear sky to see the northern lights, Click here to view satellite images and the forecast.
3. Kp Index (Solar Activity)
The Kp index is a scale of 0-9 that represents the level of solar activity. The higher the number the more the aurora will push south. Take a look at the maps below that are from the University of Alaska. Each map is a very accurate representation of where the aurora will normally be at local midnight for each Kp value. The shaded area colored on the map show good viewing with the potential for overhead sightings. The green line shows the farthest point south the aurora could be visible low on the northern horizon.
Kp 2-Visible Over Fairbanks, AK to Winnipeg Kp 3-Visible In North Sky In Northern MN & MI
Kp 4-Visible In North Sky In ND, MN, WI, MI Kp 5-Visible Along And North Of I-80
Kp 6-Visible In Northern Half Of USA Kp 7-Visible North Of I-40, Big Show In Midwest
Kp 8-Visible Everywhere But South Texas & FL Kp 9-Visible Everywhere, Massive Display!
4. Bz Index (Aurora Storm Potential)
The Bz index is really the icing on the cake. Anytime the Bz index is pointing south or better yet strongly south, the potential for great aurora displays goes way up. The Bz is a measure of the earth's magnetic field. As a whole the earth's magnetic field points north which cancels out a lot of the incoming solar blasts, which has a southward pointing magnetic field. When the earth's magnetic field shifts southward it is like opening a door to the solar wind, and thus great aurora displays.
Putting The Forecast To Work
Now you have all of the tools to understand the forecast. Go back to the top of the page and under the Now section you can get an immediate idea of what the aurora picture is looking like and where it is likely located. The label under Now will either say...
A Quiet label doesn't mean the aurora isn't out it means the Kp index is somewhere between a 0 and a 3 which means the aurora is unlikely to be seen in North America unless you are in Boundary Waters Canoe Area Wilderness, Canada or Alaska. Unsettled means the Kp=4, and Storm means the Kp is between 5 and 9. The aurora oval is the best guess of where the northern lights are right now. The Kp graph will give you detailed Kp information, and the gauge on the right will keep a measure of the Bz and solar wind in real time. All of that information gives you an idea of what is going on now. The short term forecast is very accurate and both sources are worth looking at. If a solar storm is forecasted and you are waiting on the right conditions to develop before heading outside, this is what you want to keep watching and refreshing. The daily and monthly outlooks are below that. Both of them begin to lose accuracy with time but they can still help you plan in the days ahead, especially if you are taking a trip north to see the aurora.
Observing The Aurora
How To Observe
After all of the waiting, the best part is watching a colorful display of northern lights dance across the night sky. You want to keep in mind a few simple but necessary tips to have the most enjoyable time. Make sure to get away from the city lights. I have seen a few displays that never appeared to be there until I drove away from light pollution. The darker the sky, the brighter the lights. Also pick a spot with good viewing to the north and northeast. Most often a display of northern lights will start low on the north/northeast horizon. Thirdly, just make sure you pack some common sense and be safe driving and enjoy.
When To Look
The quick answer is anytime the solar activity is up, the sky is clear and it is dark. However, the northern lights normally peak around local midnight +/- a couple hours. The best time to be on guard is 10pm to 2am local time but some stronger displays could have activity anytime from dusk to dawn.
Geomagnetic Storms & Sub Storms
Geomagnetic Storms take place when a CME (Coronal Mass Ejection) is ignited from the sun, typically from one or a group of sunspots. These storms often produce the aurora borealis over a lot of real estate world wide. Often times the CMEs can be detected about a day or two before hitting earth. Spaceweather.com is a good site to monitor these solar explosions.
Sub Storms are very common even on a quiet or unsettled day. These brief storms are the uptick in aurora activity that begins on earth near local midnight and the increased activity then spreads east and west around the globe. The heightened intensity may last 10 to 15 minutes up to 3 hours. The northern lights pulse in energy up and down constantly.
The Different Colors
The northern lights shine with a green, sometimes a yellow/green-whitish color most of the time. On rare occasions such as major storms the aurora will shine light red/pink to dark red. Also blue and purple shine every once in a rare while near twilight. The different colors have to do with different atoms being excited by the solar wind. The common green color is from oxygen atoms being excited at lower levels (60 to 185 miles above the ground), the rare red aurora is from oxygen atoms being excited at very high altitudes (above 185 miles). Nitrogen can occasionally cause blue or purple to shine high in the atmosphere at the tail end of twilight in the evening and right as twilight begins in the morning. This is a rare color to see especially for middle or low latitudes. Every once in a while a slightly different red color (almost crimson) can show up on the bottom of a green aurora. This happens when nitrogen is excited at 6o miles above the surface. Here is a picture of this talking place near Fairbanks, Alaska. Look at the bottom edge of the green aurora where a red/orange color mixes in, this is from the energized nitrogen atoms.
Long Term Planning
If you are planning a trip to see the northern lights, two things will help you more than anything, location and time. The closer to the aurora oval you get and the longer you stay there will increase you odds dramatically. The long range outlook above can be of some guidance when trying to forecast the northern lights several weeks out, but considering most of the big displays will not be forecasted outside of a couple days, it is a gamble. The best approach is to plan a trip where your odds are the highest. There are certainly a lot of places that could work, but I am going to focus on Fairbanks, Alaska. If the sky is clear you have a 90% chance of seeing the northern lights on any given night from late August through late April (the summer is too light to see the aurora). After taking clouds into consideration, there is about a 93% chance of seeing the northern lights during a 5 day trip...and most likely you will see them a couple times. Fall and early winter brings more clouds, but mid winter through early spring is the driest and has the most cloud free nights of the year. The aurora is more active near the spring and fall solstice which makes March a perfect month in Fairbanks. The snowpack is still thick, but temperatures don't spend nearly as much time in the sub-zero range as mid winter. During the day, you can check out Chena Hot Springs, enjoy the International Ice Art Championships or take a dog sled ride. If you don't have the time or money to take a big vacation in hopes of seeing the aurora, fear not. The sun goes through an 11-year cycle of high and low solar activity and right now we are at peak. 2013 through 2015 are expected to be very active so make sure to keep checking back at this page and good luck.
If you want to dig into some of the raw aurora data and compare it with time (time of the year, and time during a solar cycle) you can open the excel sheet above. There are a couple of trends you will notice. The first is that if you live in the United States in the middle latitudes or even on the edge of the lower latitudes the number of nights with the aurora visible varies significantly. For whatever reason though the aurora activity seems to peak in April and May, and again in October and early November. Also the peak aurora year is not the same as the solar max year. The Kp peak is delayed by a solid year and in most cycles it is around 2 years. For example, during the last solar cycle late 2000 to 2001 was the solar maximum. The peak aurora viewing year was in 2003. So in other words while this solar cycle peaks this time around (2013 or early 2014) the best aurora year may end being 2014 or 2015 in theory and 2016 will probably be a decent year as well. If you have any other questions that I haven't answered, shoot me an email and I will do my best to get you an answer. Happy Viewing!
Other Useful Links
web page views since 1/7/13