Space Weather Message Code: ALTTP4 Serial Number: 558 Issue Time: 2021 Dec 21 0713 UTC CANCEL ALERT: Type IV Radio Emission Cancel Serial Number: 557 Original Issue Time: 2021 Dec 21 0640 UTC Comment: Incorrect radio sweep type issued by observatory. NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Description: Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.
