NOAA Issues G1 Geomagnetic Storm Watch for Tonight, October 19–20: Auroras Possible Over the Northern U.S. as the Orionids Build

Updated: October 20, 2026, 8:36 AM ET · Sky desk

NOAA's Space Weather Prediction Center issued a G1 (Minor) geomagnetic storm watch on Sunday afternoon, October 18, for Monday and Tuesday, October 19 and 20. A stream of fast solar wind pouring out of a coronal hole on the sun is expected to reach Earth late Monday, and the agency says the aurora may be visible across the northern tier of the United States, naming northern Michigan and Maine. The best U.S. window falls Monday night into the early hours of Tuesday, with the moon setting after midnight and the Orionid meteor shower building toward its Wednesday peak.

What NOAA said

The watch, issued at 1:24 p.m. ET on Sunday as message WATA20, serial number 1131, predicts G1 (Minor) storm levels on both October 19 and October 20 and a return to below-storm conditions on October 21. It supersedes a narrower watch from Saturday afternoon that had flagged only Tuesday. "Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine," the watch text reads, alongside the standard G1 notes of weak power-grid fluctuations and minor effects on satellite operations.

The cause is not a solar eruption but a hole. In its forecast discussion issued at 8:30 p.m. ET Sunday, the Space Weather Prediction Center said solar wind should trend toward quiet levels "until late on 19 Oct, when influence from a positive polarity CH HSS is expected," a coronal hole high-speed stream, with elevated conditions likely to hold through October 21. Coronal holes are dark regions where the sun's magnetic field opens outward and lets wind escape faster than usual; when such a stream hits Earth's field, it stirs the same auroral displays as a mild storm. A filament eruption early Sunday produced a slow coronal mass ejection that forecasters expect to miss Earth, according to the discussion.

The agency's three-day forecast puts the highest planetary Kp index, the standard measure of geomagnetic disturbance, at 4.67 for two three-hour windows: 2 to 5 p.m. ET on Monday, when it is still daylight across the United States, and 11 p.m. ET Monday to 2 a.m. ET Tuesday, which is the one that matters for anyone with a clear northern horizon. The hours in between stay at Kp 4.33, just under the G1 threshold of 5; Tuesday night slips to Kp 3.33 to 3.67 as the stream wanes, the 3-Day Forecast shows. Separately, the sun produced an M1.6 flare at 5:03 a.m. ET Monday, recorded by NOAA's GOES-18 satellite; flares of that size are routine at this stage of the cycle and do not change the watch.

A moon that gets out of the way, and Halley's dust

Two other things are happening in the same sky. The moon reached first quarter on Sunday, October 18, at 12:12 p.m. ET, according to the U.S. Naval Observatory, so on Monday night it is a fat half-moon that sets after midnight local time, leaving the darkest hours, and the strongest forecast Kp, moon-free. The Hunter's Moon follows on October 26.

And the Orionid meteor shower, debris left by Halley's Comet, is approaching its maximum. EarthSky, citing the Royal Astronomical Society of Canada's Observer's Handbook, puts the predicted peak at 18:00 UTC on Wednesday, October 21, which makes the pre-dawn hours of Wednesday the best in the United States, with a broad plateau that spreads meteors over the mornings before and after. Expect 10 to 20 meteors per hour under a dark sky, radiating from near Orion's raised club above Betelgeuse; the radiant is highest around 2 a.m., according to EarthSky. Our Orionid 2026 guide has the full viewing plan.

Also Monday, at 3:41 p.m. ET: Japan's MMX probe is scheduled to lift off for Mars's moons, as we reported Thursday.

What it means spiritually

Facts first: a G1 watch is the lowest rung of NOAA's five-step scale, the most common kind of storm there is, and a watch is a forecast, not a sighting. Everything below is interpretation.

There is an old Inuit story, told across the north, that the aurora was once locked inside the stones along the Labrador coast until a hunter struck them with his spear and freed most of the light into the sky. The rest stayed behind as the flash in labradorite. It is a story, not mineralogy, but it holds the right posture for Monday night: the light is already on its way, and the only question is whether you go outside to meet it. A coronal hole is, literally, an opening; the sun has not erupted, it has let something through. Readers who work with the idea that solar weather touches the body should know the research is thin; what is not in doubt is that standing under a northern sky at midnight changes how a person feels.

The watch opens as the moon climbs from first quarter toward the Hunter's Moon, the waxing half of the cycle that most traditions give to building and gathering. The Orionids, dust from a comet that last passed in 1986 and returns in 2061, fall through the same hours, so a shooting star may cross a green arc. Venus, meanwhile, is retrograde and will pass between Earth and the sun late this week, so the evening star is gone from the dusk sky; the night belongs to the moon, Orion and, with luck, the aurora.

What you can do now

• Plan for Monday night, 11 p.m. to 2 a.m. in your own time zone. That is the window with the highest forecast Kp after dark. NOAA's 30-minute aurora forecast is at swpc.noaa.gov; a watch can be upgraded, downgraded or canceled; the discussion is reissued at 8:30 a.m. and 8:30 p.m. ET.
• Get north and get dark. At G1 the aurora is usually a low glow or faint arc on the northern horizon, often caught more easily by a phone camera on a long exposure than by the eye. Face north, away from city light, and give your eyes 20 minutes.
• Stay out for the meteors. After moonset, lie back and look up rather than at the radiant; Orionids are fast and leave trails. Our Orionid guide explains why the mornings of October 20 to 22 all count.
• Dress for a long wait. Northern-tier nights run cold in October; a thermos and a blanket turn a vigil into a ritual.
• Mark the next moon. The Hunter's Moon rises full on October 26; what you set in motion under this half-moon comes to light then.

Pairs well with: Labradorite Bangle Bracelet, the stone the old story says still holds a piece of the northern lights.

Sources

• NOAA Space Weather Prediction Center, Geomagnetic Storm Watch, WATA20 serial 1131, issued October 18, 2026, 1724 UTC (G1 on October 19 and 20); superseded WATA20 serial 1130 of October 17, 2026, 2014 UTC. services.swpc.noaa.gov
• NOAA SWPC, Forecast Discussion, issued October 19, 2026, 0030 UTC (coronal hole high-speed stream; filament CME expected to miss Earth). services.swpc.noaa.gov
• NOAA SWPC, 3-Day Forecast, issued October 19, 2026, 0030 UTC (Kp breakdown October 19–21). services.swpc.noaa.gov
• NOAA SWPC, GOES-18 X-ray flare list, 7 days (M1.6 at 0903 UTC October 19, 2026) and Space Weather Message SUM10R serial 930 (10 cm radio burst, 0858 UTC). services.swpc.noaa.gov
• NOAA Space Weather Scales, geomagnetic storms G1–G5. spaceweather.gov
• U.S. Naval Observatory, Moon phases 2026 (First Quarter October 18, 16:12 UTC; Full Moon October 26, 04:12 UTC). aa.usno.navy.mil
• EarthSky, "Everything you need to know: Orionid meteor shower," 2026 edition (peak 18 UTC October 21 per RASC Observer's Handbook; 10–20 per hour). earthsky.org
• EarthSky, "Sun news," entries of October 17 and 18, 2026 (secondary source on the coronal hole and arrival timing). earthsky.org
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Cover image: generated illustration of a G1-level aurora over a northern U.S. lakeshore; it is not a photograph of this event. The spiritual readings in this article are tradition and lived practice, not scientifically proven.