ZENITH
ALERT
MAJOR ALERT SINCE SEPTEMBER 7
Solar Terrestrial Activity Report september 14 - september
21
The geomagnetic field is unsettled to major storm on September
14. Solar wind speed ranged between 584 and 862 (all day average
735) km/sec. Solar flux measured at 17h UTC on 2.8 GHz is
113.6 (the measurements at both 20 and 23h UTC are flare enhanced).
The planetary A index is 51 (STAR Ap - based on the mean of
three hour interval ap indices: 51.1).
Three hour interval K indices: 65465344 (planetary), 55565143
(Boulder).
The background x-ray flux is at the class B7 level.
september 15 : At midnight there is 1 spotted region on the
visible solar disk. The solar flare activity level is high.
A total of 9 C, 1 M and 3 X class events is recorded during
the day.
september 16 : Region 10808 displayed significant changes
as the main penumbra increased its areal coverage. The negative
polarity in the southern half of the penumbra is moving slowly
westwards as a path has opened to the main negative polarity
areas in the west. The main penumbra has positive polarity
umbrae in the north as well as in the southernmost part where
a few patches of positive polarity have emerged. The
main penumbra is extremely complex and further X class proton
flares are possible. Flares: C4.3 at 00:58, C3.4 at 03:27,
C1.5 at 04:00, C1.9 at 04:18, C5.1 at 04:45 (associated with
a weak type IV radio sweep), C1.2 at 06:35, C1.8 at 08:28,
M1.3 at 11:21, C4.5 at 13:43, C2.9 at 19:05, impulsive X1.5
at 19:27, long duration X1.5/2B proton event peaking
at 20:05 (this event is triggered by the preceding X1.5 impulsive
flare and is associated with a large halo CME) and X1.7 at
23:22 UTC.
Coronal mass ejections :
September 15 : At least a partial halo CME is associated with
an M3 LDE in region 10808 just after noon.
September 16 - 18 : A large, fast full halo CME is associated
with the X1 long duration event which peaked at 20:05 UTC
in region 10808.
Coronal holes :
Coronal holes cannot currently be reliably observed.
Forecast :
The geomagnetic field is expected to
be unsettled to minor storm on September 14. The CME observed
during the evening of September 13 could reach Earth just
before midnight on September 14 or early on September 15 and
cause minor to extremely severe (Kp 5-9) geomagnetic storming.
Unsettled to major storm is likely on September 16 barring
further CME activity in region 10808.
archive
schedules and alert since 2004
