Forecaster David Marshall at the NWS Space Weather Prediction Center.
While the bulk of the operations at the National Weather Service (NWS) deals with atmospheric weather conditions, SWPC has the charge of forecasting the weather outside of our atmosphere, and how it interacts with systems on and orbiting earth. “Similar to terrestrial weather, as forecasters, we analyze current conditions, and predict anticipated activity in the near future, however, we are looking at different data sets and different phenomenon.
All of our activity sources back to the Sun first, and then the 93 million miles between the Sun and Earth, and then finally, the near-Earth and geophysical environments.” –says David. Similar to our forecasts on Earth, SWPC relies on observational data and forecast models to help predict the future. But, unlike here on the surface, we don’t have a dense network of hourly surface observations to use. “We certainly don’t have the problem of too much data” - David states. Most of the observations come from satellite sources; DSCOVR, GOES, SOHO, and SDO are all satellites which focus on, or contain instruments that monitor space weather. There is also a network of Earth-based systems that monitor variations of Earth’s magnetic field, solar optics, and radio measurements obtained through partnerships with the U.S. Geological Survey, the Air Force, and the National Solar Observatory. However, David notes –“There is a lot of distance in the 93 million miles between Sun and Earth, where we currently don’t have observations.” To fill those gaps, models, similar to those NWS meteorologists use to forecast your weather, are beginning to be developed for space weather concerns. David tells us – “This is a growing area in our field, but much more development in this area is needed. The sparseness of observations in space creates some limitations to these tools.” Despite these limitations, some models are now operational. Models are now used for forecasting the motion of Coronal Mass Ejections, accumulation or dissipation of particles near orbiting satellites, and variations in the Earth’s magnetic field.
Efforts continue to enhance space weather modelling - “We now have an experimental model, known as Ovation, to help users see the Aurora, which can be a rare and elusive event, especially down in most of the lower 48 states. It generally takes a fairly strong G3 or G4 level geomagnetic storm, for it to be seen well across the northern states of the lower 48. These storms also need to occur at the right time of night, with little or no low clouds, ideally with no Moon, and little or no light pollution.”
Why invest so much into something with seemingly so little impact to our planet? David explains – “Similar to Tsunami Warning or Volcanic Ash Emissions, Space Weather has the potential for low frequency, but high impact events.” Day-to-day impacts of these solar storms are relatively minor, with low level magnetic disturbances and intermittent radio blackouts. However, the sun has the possibility to unleash storms which could do far worse, wreaking havoc on our orbiting satellites, interrupting our GPS systems, and stressing the power grids. These have happened before, the Carrington Event in 1859, and the Montreal Blackout in 1989 are both examples of higher end impacts from space weather. In order to keep potential impacts minimal the SWPC has developed relationships with industries that could have significant impacts in the case of a severe solar storm. These customers include; airlines, satellite operations, NASA, GPS applications, power utilities, oil pipelines, FEMA, all the way down to the casual Aurora enthusiast, and even pigeon racers. By working closely with these partners, industries know what to do and when to do it when the SWPC issues an alert.
Credit: SWPC
These solar storms are much different than the storms that WFOs forecast here on Earth. Instead of clouds, rain, and wind, solar storms are massive explosions on the surface of the sun that emit huge amounts of electromagnetic energy (many many times that of the largest nuclear explosions), and sometimes produce Coronal Mass Ejections (CME) that dispatch huge clouds of ionized plasma out into space, and sometimes at Earth. Like storms on Earth (Hurricanes, tornadoes) however, the NWS categorizes them in order of severity on the NOAA Space Weather Scales. Though, admittedly are less creatively named than the Saffir-Simpson or Enhanced Fujita scales. According to David – ‘The NOAA scales are divided into three categories; R, S, and G and range from levels 1 through 5, with 5 being the most significant”.
He continues – “R Scale events are Radio Blackouts, which are caused by solar flares. When a solar flare occurs, the ionosphere (a highly ionized section of the earth’s atmosphere from about 60 to 1,000 km above the earth) on the day lit side of Earth is bombarded by X-ray energy which results in degradation or loss of the ability for High Frequency radio communications to work. This mostly impacts aircraft flying over large bodies of water or in remote areas. The impacts of these events can persist for tens of minutes to a few hours, depending on the magnitude and the profile of the flare. During active days in our busy season, the high end of the solar cycle, these events can happen several times per day in the R1 or R2 range. We forecast the probability of these events based on the magnetic complexity and other characteristics of sunspots on the visible portion of the Sun facing Earth. R4 or R5 events are far less common, occurring only a few times per every 11 year solar cycle, or less.
S scale events are Solar Radiation Storms. These events occur far less frequently than the other two categories. Solar Radiation Storms can occur if high energy protons are accelerated through Space, out ahead of eruptions that occur back at the Sun. They will be observed at GOES only if they happen to follow magnetic field lines that allow them to propagate to/past the near-earth environment. The primary concern related to these events is for astronauts outside the protection of Earth’s atmosphere, like on the International Space Station. SWPC helps support that mission through a partnership with an office at NASA Kennedy in Houstin. These events can also cause damage to satellite missions, and can disrupt the use of High Frequency communications over the Polar Regions.
Finally, G Scale events are Geomagnetic Storms. These are the events that provide SWPC the greatest level of interest. In short, a geomagnetic storm is the result of disturbances or fluctuations to Earth’s magnetic field, caused by variations in solar wind conditions, or by passing transient clouds of plasma that tear off the Sun - known as Coronal Mass Ejections or CMEs. When these magnetic fluctuations occur, they can produce induced electric currents that run through the atmosphere and through the ground on Earth. While not dangerous to humans on the ground, these currents can be absorbed into long line transmission systems for the power grid, which can cause operational issues for the system managers. During these events, GPS accuracy can be degraded and there can also be increased satellite drag – upsetting the orbit of satellites in space. The upside of a G-scale event is that you might get lucky enough to see the Aurora in places where it is usually not visible.”
Credit: SWPC
Also similar to Earth, these storms vary seasonally, though on a much longer scale. Instead of a yearly cycle, the solar cycle spans 11 years. “The cycle consists of 3-4 years of more activity (increased sunspots) on the solar disk, with the peak known as Solar Maximum, before a waning period of 6-7 years where there are less and less spots/activity.” It is important to note though that as is the case on Earth. Storms can and do develop outside of their “season” and it is important to constantly monitor the situation. As to where we are in the current solar cycle, David states –“We are now on the waning downslope from the recent Solar Maximum, which occurred early in 2014. The next Solar Maximum is expected in 2024 or 2025. We still see periods with interesting, and sometimes complex regions - those which could potentially produce significant storms - however, much less frequently these days than a few years ago.”
Thank you for reading about what goes on at the NWS’s Space Weather Prediction Center! Want to know more about space weather and NWS activities related to it? Please visit the Space Weather Prediction Center website, SpaceWeather.gov and look up Frequently Asked Questions. If you’re more interested in our more terrestrial weather, be sure the check Weather.gov for your daily forecast.
