SEC Space Weather Advisory 13 June 2000

Official Space Weather Advisory issued by NOAA Space Environment Center Boulder, Colorado,
USA

SPACE WEATHER OUTLOOK

2000 June 13 at 02:36 p.m. MDT (2000 June 13 2036 UT)

Summary For June 5-11 Space weather reached strong levels during the week. Category R2
(moderate) and R3 (strong) radio blackouts occurred on June 6, 7, and 10 due to major solar
flares. Category R3 radio blackouts may result in some or all effects on the following on the
sunlit portion of Earth: wide-area blackout of high-frequency (HF) communication signals with
loss of radio contact for mariners and en route aviators for about an hour, and low-frequency
navigation signals degraded for about an hour affecting maritime and general aviation
positioning. A category G3 (strong) geomagnetic storm occurred on June 8. The storm was a
consequence of a major flare and coronal mass ejection (CME) that occurred on June 6.
Category G3 storms may cause some or all effects on the following: power system grids may
require voltage corrections, false alarms may be triggered on protection devices, and high
“gas-in-oil” transformer readings may occur; spacecraft may experience surface charging,
increased drag, and orientation problems may need corrections; HF (high-frequency) radio
propagation may be intermittent; intermittent low-frequency radio navigation and satellite
navigation problems may occur; and the aurora may be seen as low as 50 degrees latitude. Two
category S1 (minor) solar radiation storms were detected by the NOAA GOES spacecraft
during June 7 – 10. Category S1 radiation storms may cause minor impacts on HF radio
communications in the polar regions.

Outlook For June 14-20 Space weather is expected to decrease to minor levels. Isolated
category R1 (minor) radio blackouts are possible. A category S1 (minor) solar radiation storm
is also possible early in the period.