Space Weather Advisory Outlook #02- 22 — 28 May 2002

SPACE WEATHER ADVISORY OUTLOOK #02- 22

2002 May 28 at 01:10 p.m. MDT (2002 May 28 1910 UTC)

**** SPACE WEATHER OUTLOOK ****

Summary For May 20-26

Space weather reached strong levels during the period. A category R3
(strong) radio blackout occurred at 9:27 a.m. MDT on May 20 (2002 May
20 1527 UTC). A category R2 (moderate) radio blackout occurred at 4:53
a.m. MDT on May 20 (2002 May 20 1053 UTC). Both were the result of
major solar flares from NOAA (sunspot) Region 9961. Isolated category
R1 (minor) radio blackouts occurred on 21 and 24 May due to
moderate-sized solar flares. A category S2 (moderate) solar radiation
storm was detected at geo-synchronous orbit by NOAA GOES satellites
during May 22 – 24. This storm followed an impressive filament eruption
on May 22 from the Sun’s southwest quadrant. This filament eruption
also spawned a fast full-halo CME, which passed Earth on May 23.
Category G1 (minor) to G3 (strong) geomagnetic storms occurred on May
23 as a result of the CME passage with G3 storm conditions detected
during 6:00 a.m. – 12:00 p.m. MDT (2002 May 23 1200 – 1800 UTC). The
NASA Advanced Composition Explorer (ACE) spacecraft detected solar
winds as high as 1000 km/sec (roughly 2,200,000 mph) during the CME
passage. The storm subsided late on May 23. For a list of adverse
system effects caused by space weather storms, please refer to the NOAA
Space Weather Scales.

Outlook For May 29-June 4

Space weather is expected to decrease to minor levels. Isolated Category
R1 (minor) radio blackouts are likely during the period.

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. More
information is available at SEC’s Web site http://sec.noaa.gov or
(303) 497-5127. The NOAA Public Affairs contact is Barbara McGehan
at bmcgehan@boulder.noaa.gov or (303) 497-6288.