Aurora forecast: what you must know
There are four types of forecasts: 11-year solar cycle forecast, 27-day geomagnetic activity forecast, 3-day geomagnetic activity forecast, and real-time aurora forecast. What do they really mean, and how to use them right?
A hut with a fireplace in Lapland where you can get warm and check the forecasts
Similar to the weather forecasts, the aurora ones can't be 100% accurate. But they can help to predict the aurora and go to the right place at the right time. That's what we are looking for as aurora photographers. So, let's talk about all of them.
11-year solar cycle forecast
Solar activity changes in time with an 11-year cycle. Most events that cause the aurora occurs during and at the end of the solar maximum. Accordingly, your chances of capturing the most bright and active aurora increase in these years. The good news is we are heading toward the solar maximum right now. So, you can expect more breathtaking auroras in the coming years. Also, increasing solar activity means you have more chances to see the aurora in lower latitudes than usual. Arctic nature is terrific, but what about southern lights dancing above a lavender field in Tasmania or New Zealand?
27-day Kp forecast
It's a geomagnetic activity forecast that predicts future activities based on previously observed ones. It's possible because the sun's active regions usually last several months. They turn to the Earth every 27 days with the sun's rotation. Thus, if there is a high geomagnetic activity today, you can expect more or less the same level in 27 days. Important to mention that desired geomagnetic storm may occur 1-2 days earlier or later. So, check the 3-day and real-time forecasts for more accurate data. The forecast shows the maximum expected Kp for each day. Combine this forecast with the moon phase and dark hours calendars. It will be an excellent tool for planning your aurora photography trip. Moreover, you can repeat the estimates 1-2 more times and know what to expect in the coming 2-3 months.
3-day Kp forecast
The forecast is based on observations of the current activity on the sun's surface. When the solar wind leaves the sun, it travels 150 million km to the Earth in about 3 days and causes geomagnetic activity and the aurora. The forecast predicts the maximum expected Kp for each 3 hours interval for 3 coming days. The problem is that it's hard to predict the direction of the wind and if it hits the Earth. Also, measuring solar wind magnetic field and other parameters is impossible when it leaves the sun. This makes the forecast less accurate in predicting the aurora. Nevertheless, the 3-day Kp forecast with weather and cloud coverage forecasts allows you to make plans for the coming nights.
Real-time aurora forecast
When the solar wind is about to reach the Earth's magnetosphere, it passes stationary satellites in the so-called L1 point, which is 1.5 million km from the Earth. The satellites measure solar wind speed, density, and magnetic field parameters. That allows for accurately predicting the aurora with about an hour lead time depending on solar wind speed. You can check the real-time forecast before going on location and during the night to see if it confirms the 3-day forecast prediction and correct your plans accordingly.
