In the wake of a promising northern lights forecast for the weekend, there’s a chance of further displays across parts of the northern U.S. overnight on Saturday, Aug. 1, through Sunday, Aug. 2, as a coronal mass ejection that left the sun on July 30 strikes Earth’s magnetic field.
According to Spaceweather.com, the CME — a cloud of magnetic fields and charged particles — left the sun in the wake of a solar flare that, despite being weak, lasted for many hours. The CME is expected to arrive on Sunday, Aug. 2, when it could cause a G2-class geomagnetic storm and auroras across northern-tier US states.
The short summer nights, combined with this week’s full moon, may also make faint aurora harder to see, with a faint display likely only be visible to those who photograph the northern lights with a phone. Cameras often detect faint aurora before the human eye can see color clearly.
The forecast comes as noctilucent clouds are being seen in the northern hemisphere, a comet brightens and two meteor showers peak — just weeks before a total solar eclipse, for which solar eclipse glasses are required.
Northern Alert For Tonight And This Weekend
According to a forecast by space weather experts at the National Oceanic and Atmospheric Administration, early on Sunday, Aug. 2, a G2-class geomagnetic storm is predicted, with Kp 6 conditions forecast. In its wake, a G1-class geomagnetic storm is expected. “G1-G2 (Minor-Moderate) geomagnetic storms are likely on 02 Aug due to the influence of a CME that left the Sun on 30 Jul,” reads the NOAA forecast.
The UK Met Office’s Space Weather Operations Center is forecasting a similar scenario, stating that “a stronger enhancement is probable late 01 August or early 02 August (UTC) due to a Coronal Mass Ejection arrival from the 30 July Coronal Mass Ejection.”
Northern Lights Forecast For The U.S.
A G1 geomagnetic storm can sometimes make the aurora visible from northern U.S. states, particularly from locations close to the Canadian border. Potential viewing areas may include parts of Washington, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Michigan, Maine, Vermont and New Hampshire. Widespread visibility across the central or southern U.S. is not expected under the current forecast.
In the event of a G2 geomagnetic storm, faint aurora may be seen from northern parts of Oregon, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, New York, Vermont and New Hampshire.
Skywatchers should look toward the northern horizon during the darkest part of the night. A location away from streetlights and other sources of light pollution will offer the best chance of seeing faint aurora.
Aurora Alert: Interplanetary Magnetic Field
Aurora visibility will ultimately depend on the strength of the solar wind, cloud cover, local light pollution and the orientation of the interplanetary magnetic field. The latter, known as Bz, is one of the most important factors. When Bz points south, it can connect more efficiently with Earth’s magnetic field, allowing energy and charged particles to enter the magnetosphere. A sustained period of southward Bz could make the aurora brighter and push it farther south than expected. If Bz remains northward, however, the resulting display may be weak or restricted to higher latitudes.
Aurora Alerts: Latest Updates
Aurora forecasts can change quickly after a high-speed solar wind stream reaches Earth. To check visibility in real time, use NOAA’s 30-minute aurora forecast or download apps such as Aurora Now, My Aurora Forecast or Glendale Aurora for up-to-the-minute alerts and live solar wind data.
Smartphone cameras using Night Mode or a long-exposure setting may detect faint green, red or purple aurora before the colors become obvious to the naked eye.
Wishing you clear skies and wide eyes.