ARRL

News

Solar Tumult Continues, Aurora Possible on Halloween

10/29/2013

Words like “wall-to-wall stations” and “phenomenal conditions” punctuated post-contest reports from last weekend’s CQ World Wide DX Contest (SSB). Participants have Ol’ Sol to thank, as sunspot numbers leaped into the vicinity of 150.

The very active solar conditions did little to help those who favor or concentrate on the lower bands, but 10 meter operators experienced sustained openings during the weekend, punctuated by occasional radio blackouts. And, it appears, this period of exalted solar activity is not yet past.

The Space Weather Prediction Center (SWPC) reports that the sun’s “somnolent region 1882 reawakened suddenly” October 28 at 1515 UTC with an R1 (minor) radio blackout. An Earth-directed coronal mass ejection (CME) launched from the Sun during the eruption was expected to generate G1 (minor) geomagnetic storm levels on October 31, opening the possibility of Halloween auroral displays.

Actually, a series of CMEs will sweep past Earth this week. Spaceweather.com says the first three are expected to deliver glancing blows, “possibly having little effect,” with a greater likelihood of a more direct hit October 31, when the CME from Earth-facing sunspot 1882 is awaited, propelled in Earth’s direction by an M4-class flare on October 28. “High-latitude sky watchers should be alert for auroras on Halloween,” SpaceWeather.com says.

Noting the high number of sunspots, forecasters say three of them — including 1882 — “post a threat for strong eruptions.” NOAA forecasters estimate a 70 percent chance of M-class flares and a 35 percent chance of X-class flares on October 29.

 



Back