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National Oceanic and Atmospheric Administration

Thursday, July 24, 2025 08:48:58 UTC

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NOAA Scales mini

R1 (Minor) Radio Blackout Impacts
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HF Radio: Weak or minor degradation of HF radio communication on sunlit side, occasional loss of radio contact.
Navigation: Low-frequency navigation signals degraded for brief intervals.
More about the NOAA Space Weather Scales

G1 (Minor) Geomagnetic Storm WATCH Issued for 20-21 Sep 2015

WSA-ENLIL model output
G1 (Minor) Geomagnetic Storm WATCH Issued for 20-21 Sep 2015
published: Tuesday, September 22, 2015 18:06 UTC

Isolated periods of minor geomagnetic storm conditions are likely on 20 Sep due to the influence of a positive polarity coronal hole high speed stream (CH HSS). G1 storms are likely again early on 21 Sep due to continued CH HSS influence in addition to the anticipated arrival of a CME from 18 Sep.