SpaceWeatherTracker · NOAA sources
Solar Flare Alerts & Radio Blackouts
A solar flare is a burst of electromagnetic radiation from the Sun. NOAA’s R-scale describes associated radio-blackout severity; a flare alert does not automatically predict an aurora or a geomagnetic storm.
Latest geomagnetic reading
Kp 2.0
Below geomagnetic storm threshold
NOAA interval begins
Kp summarizes a three-hour interval. The page checks sources every five minutes; that is not NOAA's observation cadence.
What X-ray classes mean
Flare classes A, B, C, M and X categorize peak soft X-ray flux. A numeric suffix refines the class. The class is not a direct measurement of an Earth-impacting CME.
Where radio blackouts occur
Flare-driven high-frequency radio impacts primarily affect the sunlit side of Earth. NOAA notices describe the event and relevant thresholds; ground-level weather warnings are a different service.
Will a flare cause northern lights?
A flare can accompany a CME, but a CME must interact with Earth’s environment to drive a geomagnetic storm. Direction, arrival time and magnetic orientation matter.
Watch the Sun
Use the solar-flare monitor for measurements and SpaceWeatherTracker TV for source-labeled solar imagery. Recorded footage is not evidence of a flare happening at this instant.
Recent NOAA notices
All notices and validity detailssummary · R2
R2 Radio Blackout Summary
Issued
NOAA product text
Space Weather Message Code: SUMXM5 Serial Number: 328 Issue Time: 2026 Oct 10 1527 UTC SUMMARY: X-ray Event exceeded M5 Begin Time: 2026 Oct 10 1458 UTC Maximum Time: 2026 Oct 10 1510 UTC End Time: 2026 Oct 10 1520 UTC Xray Class: M6.4 Optical Class: Location: N08W50 Noaa Scale: R2 - Moderate Comment: NOAA Scale: R2 - Moderate NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact centered primarily on sub-solar point on the sunlit side of Earth. Radio - Limited blackout of HF (high frequency) radio communication for tens of minutes.
alert
Type II Radio Emission
Issued
NOAA product text
Space Weather Message Code: ALTTP2 Serial Number: 1532 Issue Time: 2026 Oct 10 1526 UTC ALERT: Type II Radio Emission Begin Time: 2026 Oct 10 1515 UTC Estimate Velocity: 929 km/s Comment:
summary
10cm Radio Burst
Issued
NOAA product text
Space Weather Message Code: SUM10R Serial Number: 929 Issue Time: 2026 Oct 10 1519 UTC SUMMARY: 10cm Radio Burst Begin Time: 2026 Oct 10 1505 UTC Maximum Time: 2026 Oct 10 1506 UTC End Time: 2026 Oct 10 1509 UTC Peak Flux: 240 sfu Duration: 4 minutes Latest Penticton Noon Flux: 121 sfu Comment:
alert · R2
R2 Radio Blackout Alert
Issued
NOAA product text
Space Weather Message Code: ALTXMF Serial Number: 543 Issue Time: 2026 Oct 10 1509 UTC ALERT: X-Ray Flux exceeded M5 Threshold Reached: 2026 Oct 10 1507 UTC Noaa Scale: R2 - Moderate Comment: NOAA Scale: R2 - Moderate NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see http://www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap.
alert
Type II Radio Emission
Issued
NOAA product text
Space Weather Message Code: ALTTP2 Serial Number: 1531 Issue Time: 2026 Oct 08 1646 UTC ALERT: Type II Radio Emission Begin Time: 2026 Oct 08 1542 UTC Estimate Velocity: 4125 km/s Comment: ** Corrected for begin time. Type II speed recorded by Sagamore Hill RSTN site. CORRECTED
Recent products can include expired, superseded or cancelled notices. Read the original product before treating it as an active warning.
Sources and limitations
Independent interpretation by SpaceWeatherTracker; official measurements and notices are attributed to NOAA. Not for safety-of-life or operational decisions.