NOAA Logo

NWS Logo

Organizations

Space Weather Prediction Center

National Oceanic and Atmospheric Administration

Tuesday, January 16, 2018 21:51:21

Main menu

NOAA Scales mini

minimize icon
Space Weather Conditions
24-Hour Observed Maximums
R
no data
S
no data
G
no data
Latest Observed
R
no data
S
no data
G
no data
R1-R2 --
R3-R5 --
S1 or greater --
G
no data
R1-R2 --
R3-R5 --
S1 or greater --
G
no data
R1-R2 --
R3-R5 --
S1 or greater --
G
no data
maximize icon
R
no data
S
no data
G
no data
Current Space Weather Conditions
R1 (Minor) Radio Blackout Impacts
close
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.