Space Weather Outlook #00-34 25 July 2000

Official Space Weather Advisory issued by NOAA Space Environment Center

Boulder, Colorado, USA

SPACE WEATHER OUTLOOK #00- 34

2000 July 25 at 02:44 p.m. MDT (2000 July 25 2044 UT)

**** SPACE WEATHER OUTLOOK ****

Summary For July 17-23
Space weather reached moderate levels due to category R2 (moderate)
radio blackouts and a category G2 (moderate) geomagnetic storm. A total
of three category R2 radio blackouts occurred during July 19 – 21 due
to large solar flares. Category R2 radio blackouts typically result in
the following effects on the sunlit portion of Earth: limited blackout
of high-frequency radio communication signals resulting in loss of
contact for tens of minutes for mariners and en route aviators, and
degradation of low-frequency navigation signals for tens of minutes
affecting maritime and general aviation positioning. A category S1
(minor) solar radiation storm was detected by the NOAA GOES spacecraft
during July 22 – 23 and resulted in minor impacts on high-frequency
radio communications in the polar regions. Category G2 (moderate)
geomagnetic storm conditions occurred on July 20 due to a CME (coronal
mass ejection) passage at Earth. Moderate geomagnetic storm conditions
normally result in some or all of the following system effects: voltage
alarms are possible on high latitude power systems (but tripping is not
likely); spacecraft operations require corrective actions by ground
control and changes in atmospheric drag affect orbital predictions; and
high-frequency radio communication signals fade at high latitudes.

Outlook For July 26-August 1
Category R1 (minor) to R2 (moderate) radio blackouts are expected during
the period with effects similar to those mentioned above. Category G1
(minor) geomagnetic storm conditions are expected during July 27 – 28
following a CME observed earlier today. G1-level geomagnetic storms
will normally result in minor impacts on satellite operations and
high-latitude power systems.

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.