Status Report

Space Weather Outlook #01-4 — 11 Apr 2001

By SpaceRef Editor
April 11, 2001
Filed under ,

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


2001 April 10 at 06:17 p.m. MDT (2001 April 11 0017 UT)


Summary For April 2-8

Space weather increased to category 5 (extreme) levels on April 2. A
category R5 (extreme) radio blackout occurred at 3:51 p.m. MDT on April
2 (2001 April 02 2151 UTC) due to a massive solar flare. This solar
flare was the largest yet seen during the current sunspot cycle (Cycle
23). The sunspot group that produced the flare (Region 9393) was also
the largest group yet seen during Cycle 23. Category R5 radio
blackouts are rare and normally cause adverse effects on high-frequency
radio communication and low-frequency navigation signals for many hours
on the entire sunlit portion of Earth. Isolated category R2 (moderate)
to R3 (strong) radio blackouts also occurred during the period. A
category S1 (minor) radiation storm occurred during April 02 – 06 as a
result of the April 2 flare. Category S1 solar radiation storms
typically result in minor impacts on high-frequency radio communication
in the polar regions. A brief category G2 (moderate) geomagnetic storm
occurred on April 8. Category G1 (minor) storm conditions occurred
during April 4 – 5. These geomagnetic storms were due to a series of
CME passages at Earth associated with major solar flare activity from
Region 9393, which rotated to the far side of the Sun on April 3; and
from Region 9415, which will be on the the face of the Sun until April
16. Category G2 geomagnetic storms normally result in adverse effects
on power systems and high-frequency communications at high latitudes,
and spacecraft operations. Aurora may also occur along the northern
tier of the U.S. during category G2 storms.

Outlook For April 11-17

Space weather is expected to reach category 3 (strong) levels during the
outlook period. A geomagnetic storm reaching G2 to G3 levels is
expected to occur during April 11 – 12 due to a CME passage. Region
9415 is expected to produce isolated category R2 to R3 radio blackouts
before it rotates to the far side of the Sun on April 16. A category S1
solar radiation storm began on April 10 and is expected to continue
through April 11. Additional S1 storms will be possible during the

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 or
(303) 497-5127. The NOAA Public Affairs contact is Barbara McGehan
at or (303) 497-6288.

SpaceRef staff editor.