NOAA
Summary
For April 23-29
Space weather
reached category 2 (moderate) levels on the NOAA Space Weather
Scale (SWS). A category R2 (moderate) radio blackout reached its
peak at 7:12 a.m. MDT on April 26 (2001 April 26 1312 UTC). The
blackout was the result of a major solar flare from NOAA sunspot
Region 9433, which is currently crossing to the far side of the
Sun. Category R2 radio blackouts normally result in adverse effects
on high-frequency (HF) radio communications and low-frequency
navigation signals on the sunlit side of Earth (for a more complete
list of system effects, please refer to the NOAA SWS).
Region 9433
also caused a number of category R1 (minor) radio blackouts during
April 23 - 27. The major flare of April 26 spawned an Earth-directed
coronal mass ejection (CME) which reached Earth early on April
28. The CME caused intermittent category G1 (minor) geomagnetic
storm conditions on April 28. Category G1 storms typically cause
minor effects on power systems and spacecraft operations. A brief
category S1 (minor) solar radiation storm occurred on April 28,
also related to the CME passage. This brief, weak storm may have
caused minor impacts on HF radio communication in the polar regions.
Outlook
For May 2-8
Space weather
is expected to decrease to minor levels. Isolated category R1
(minor) radio blackouts will be possible during the period. There
will be a slight chance for a category G1 (minor) geomagnetic
storm on May 4 due to an expected increase in solar wind velocities
related to a coronal hole.
Data used
to provide space weather services are contributed by NOAA, USAF,
NASA, NSF, USGS, the International Space Environment Services
and other observatories, universities, and institutions.
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