Friday 16 October
Expected: G0 (none)
- Radio blackout R1–R2
- 20%
- Radiation storm S1+
- 5%
NOAA data, checked 22:20 UTC
Space weather alerts
Right now: G0 (none). Highest Kp expected in the next 3 days: 4.0. 3 NOAA watches, warnings or alerts in the last 72 hours.
NOAA levels right now
NOAA rates space weather on three scales from 1 (minor) to 5 (extreme). Only the G scale matters for the northern lights.
Geomagnetic storms (G) G0 (none)
The aurora scale: the higher the G level, the further from the poles the lights reach.
Highest yesterday: G0 (none)
Radio blackouts (R) R0 (none)
Caused by solar flares. Disturbs shortwave radio on the day side of Earth; no effect on the aurora.
Highest yesterday: R1 (minor)
Solar radiation storms (S) S0 (none)
Fast particles from the Sun. Matters for satellites and polar flights; no direct effect on the aurora.
Highest yesterday: S0 (none)
Next 3 days
NOAA's expected storm level and chances for each UTC day. A watch is issued when a storm is likely.
Saturday 17 October
Expected: G0 (none)
Highest Kp: 4.0
- Active (Kp 4)
- 45%
- Minor storm (G1)
- 5%
- Moderate storm (G2)
- 1%
- Strong storm or more (G3+)
- 1%
- Radio blackout R1–R2
- 20%
- Radiation storm S1+
- 5%
Sunday 18 October
Expected: G0 (none)
Highest Kp: 1.7
- Active (Kp 4)
- 15%
- Minor storm (G1)
- 1%
- Moderate storm (G2)
- 1%
- Strong storm or more (G3+)
- 1%
- Radio blackout R1–R2
- 20%
- Radiation storm S1+
- 5%
What G1 to G5 mean for the aurora
Each step up the G scale pushes the aurora further from the poles. The highlighted level is the highest expected in the next 3 days.
- G1 (minor) Kp 5
Minor storm. Visible in Scotland, southern Scandinavia and the northern US states; low on the northern horizon.
- G2 (moderate) Kp 6
Moderate storm. Can reach northern England, Denmark, northern Germany and the US Midwest — often easier to see in photos.
- G3 (strong) Kp 7
Strong storm. Visible across the UK, the Netherlands, Germany and Poland; red glow in photos from France and the Alps.
- G4 (severe) Kp 8
Severe storm. Seen by eye in central Europe; red sky in photos from northern Italy, Spain and the Balkans. About 100 times per solar cycle, mostly near its peak.
- G5 (extreme) Kp 9
Extreme storm. Seen across Europe and the US, in photos as far as the Mediterranean (May 2024). Very rare.
No storm. The aurora stays near the Arctic Circle: Lapland, northern Norway, Iceland, Alaska and northern Canada.
3-day Kp forecast by 3-hour block
NOAA's forecast Kp for each 3-hour block. Kp 5 and above is a geomagnetic storm (G1 or more).
| Time (UTC) | Sat 17 Oct | Sun 18 Oct | Mon 19 Oct |
|---|---|---|---|
| 00–03 | 4.00 | 1.67 | 1.67 |
| 03–06 | 3.33 | 1.67 | 1.33 |
| 06–09 | 2.00 | 1.33 | 1.33 |
| 09–12 | 1.33 | 1.33 | 1.33 |
| 12–15 | 1.33 | 1.33 | 1.33 |
| 15–18 | 1.33 | 1.33 | 1.33 |
| 18–21 | 2.00 | 1.33 | 1.67 |
| 21–00 | 1.67 | 1.67 | 1.67 |
Times and days are in UTC (universal time). NOAA forecast issued 16 Oct, 22:05 UTC
Watches, warnings and alerts (last 72 hours)
A watch means a storm is possible in the next days, a warning means it is expected within hours, an alert means a level has just been reached, and a summary reports an event that has ended.
Warnings (1)
-
Warning: Kp 4 is expected within hours — good aurora in the Arctic, low on the horizon further south.
Original NOAA message (English)
Space Weather Message Code: WARK04 Serial Number: 5436 Issue Time: 2026 Oct 16 1938 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2026 Oct 16 1938 UTC Valid To: 2026 Oct 17 0300 UTC Warning Conditions: Onset Comment: NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.
Alerts (2)
-
Alert: Kp 4 has been reached — active aurora at high latitudes.
Original NOAA message (English)
Space Weather Message Code: ALTK04 Serial Number: 2691 Issue Time: 2026 Oct 16 1939 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2026 Oct 16 1940 UTC Synoptic Period: 1800-2100 Active Warning: YES Comment: NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.
-
Many fast electrons in orbit around Earth. This matters for satellites, not for the aurora.
Original NOAA message (English)
Space Weather Message Code: ALTEF3 Serial Number: 3754 Issue Time: 2026 Oct 16 1419 UTC ALERT: Electron 2MeV Integral Flux exceeded 1,000pfu Threshold Reached: 2026 Oct 16 1345 UTC Station: GOES-19 Comment:
Where to go next
Where can I see the aurora tonight? Live forecast: Kp, solar wind and the aurora oval
Source: NOAA Space Weather Prediction Center (alerts, NOAA scales, 3-day forecast), public domain.