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National Oceanic and Atmospheric Administration

Thursday, March 28, 2024 13:32:54

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NOAA Scales mini

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Space Weather Conditions
24-Hour Observed Maximums
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Latest Observed
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R1-R2 --
R3-R5 --
S1 or greater --
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R1-R2 --
R3-R5 --
S1 or greater --
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R1-R2 --
R3-R5 --
S1 or greater --
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Current Space Weather Conditions
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

S1 - Solar Radiation Storm Expected

ACE SIS instrument and GOES Proton Flux
S1 - Solar Radiation Storm Expected
published: Thursday, October 29, 2015 14:28 UTC

An S1 (Minor Solar Radiation Storm) Warning was issued at 29/0347 UTC due to a rise in 10 MeV protons as noted on the ACE Solar Isotope Spectrometer (SIS) instrument and the beginning of a rise in the 10 MeV flux at the GOES satellite. The S1 Warning for 10 MeV proton flux at or above 10 pfu is valid from 29/0430 UTC until 29/1700 UTC. Additionally, a warning was also issued for the 100 MeV proton flux at or above 1 pfu and is valid from 29/0445 UTC until 29/1400 UTC. This activity is a result of a coronal mass ejection (CME) that occurred from just beyond the SW limb of the Sun at around 29/0219 UTC; as noted by radio signatures known as Type II and Type IV sweeps. Locations at and just beyond the western limb are prime locations for a magnetic field line connection to Earth for energetic protons to travel at near relativistic speeds and therefore, reach Earth within 30 minutes to a few hours. Impacts due to an S1 event may include minor impacts on HF radio in the polar regions.