Archives for Tony

12th September


Solar activity reached moderate levels during the period due to a pair
of M-class flares from a yet unnumbered region just rotating around the
NE limb. The first was an M2 flare at 11/1526 UTC which had an
associated 210 sfu 10cm radio burst. The second was an M1 flare at
11/2126 UTC. Region 2157 (S14W31, Ekc/beta-gamma) had slight decay
within its smaller intermediate spot area and produced a C9/1f flare at
12/0224 UTC. Region 2158 (N16W19, Dkc/beta-gamma-delta) appeared to
have further separation in its northern spots along with a weak delta in
the NE portion of the group. The rest of the spotted regions were
either stable or in decay. No Earth-directed coronal mass ejections
(CMEs) were observed during the period.

11th September


Solar wind parameters at ACE continued to indicate a nominal solar wind
regime. Solar wind speeds began the period near 370 km/s, reached a peak
just over 400 km/s, and ended the period near 380 km/s. IMF total field
values varied slightly between 6 nT and 9 nT throughout the period,
while Bz fluctuated between +/-7 nT. Phi angle remained in a negative
(toward) orientation throughout the majority of the period, however a
solar sector boundary change to a positive (away) orientation was
observed at approximately 10/2140 UTC.

11th September


Solar activity reached high levels. Region 2158 (N16W06, Dkc/beta-gamma)
produced largest solar event of the period, an X1/2b flare (R3/Strong)
at 10/1745 UTC, along with associated Type II and Type IV radio sweeps,
a 10cm radio burst, and a full halo coronal mass ejection (CME).

While the 9 Sep CME, mentioned in previous discussions, is still
expected to arrive early in the day on 12 Sep, the latest analysis of
the WSA Enlil solar wind model indicated the CME associated with
yesterdayâ??s X1/2b flare is likely to have an Earthward component as
well. This second CME has an estimated speed near 1400 km/s and is
expected to pass the Earth’s magnetosphere mid to late day (universal
time) on 12 Sep.

Region 2158 exhibited a fairly pronounced ring of intermediate spots
surrounding the main leader spot, indicative of significant mixing and
instability, but has since shown signs of decay and reorganization of
these spots. Region 2157 (S14W18, Ekc/beta-gamma-delta) maintained its
delta magnetic configuration yet was fairly inactive during the period.
The remaining spot groups appeared to be stable and predominantly
inactive throughout the period.

10th September


Solar wind parameters at ACE continued to indicate a nominal solar wind
regime. Solar wind speeds began the period near 360 km/s before climbing
for a brief period to near 410 km/s. Speeds then returned to the mid to
upper 300 km/s range, where they remained through the end of the period.
IMF total field values held steady between 4 nT to 6 nT throughout the
period, while Bz fluctuated between +/-5 nT. Phi angle remained in a
negative (toward) orientation for the majority of the period, with a few
short-lived oscillations into a positive (away) solar sector
orientation.

10th September


Solar activity returned to low levels. Region 2157 (S14W05,
Ekc/beta-gamma-delta) produced the majority of the flare activity,
including the largest flare of the period, a C3/1n flare at 09/1226 UTC,
and a C2/Sf flare at 10/0524 UTC. This region maintained its delta
magnetic configuration and continued to exhibit signs of growth, mainly
in its intermediate spots. Region 2158 (N15E07, Dkc/beta-gamma) had
noticeable separation of the penumbral area, separating into two
separate magnetic polarities, thus losing its delta magnetic
configuration. Regions 2157 and 2158 continue to be the areas of
interest as they are still the largest and most magnetically complex
regions on the visible disk.

9th September


Solar wind parameters at ACE were indicative of a nominal solar wind
regime. Solar wind speeds ranged from a low near 360 km/s to as high as
478 km/s during the period. Speeds steadily dropped off after 09/0400
UTC and finished near the 390 km/s mark. IMF total field values remained
steady between 4 nT to 6 nT for most of the period, while Bz fluctuated
between +/-5 nT. Phi angle remained in a negative (toward) orientation
throughout the period.

9th September


Solar activity was at moderate (NOAA Scale R1-minor) levels due to a
long-duration M4/1n flare at 09/0029 UTC from Region 2158 (N15E21,
Dkc/beta-gamma-delta). This flare was originally believed to be from
Region 2157 (S15E13, Ekc/beta-gamma-delta), but after additional imagery
became available, was later determined to be from Region 2158. The M4/1n
flare had associated Type II (999 km/s estimated shock velocity) and
Type IV radio sweeps, as well as a 10cm (370 sfu) radio burst.

The associated asymmetrical, full halo coronal mass ejection (CME),
first observed in Lasco C2 imagery at 09/0006 UTC, appears to be
directed mostly northeastward, with the bulk of the ejecta well east of
the sun/Earth line. It does appear, however, that Earth may see a
glancing blow shortly after this forecast period ends.

Region 2157 and Region 2158 remain the largest and most complex regions
on the visible disk. Region 2157 exhibited minor consolidation in its
leader spots with slight development in its southern most intermediate
spots. Region 2158 had minor spot development just north and slightly
south of the large leader spot, and maintained its enhanced magnetic
complexity. Region 2155 (S21W01, Cao/beta) exhibited minor spot growth
in the smaller leader spots, but was otherwise fairly stable. The other
regions on the visible disk remained relatively unchanged.

8th September


Solar wind conditions were slightly elevated through the period with
solar wind speeds ranging from 337 km/s to around 450 km/s. Total field
ranged from 5 nT to 9 nT while the Bz component was between +7 nT and -5
nT. Phi angle remained in a negative (towards) sector.

8th September


Solar activity was at low levels. Region 2157 (S14E24,
Ekc/beta-gamma-delta) continued to produce mid-range C-class flares.
The largest was a C7 flare at 07/1943 UTC. Region 2157 had slight to
moderate growth over the period within its intermediate spot area and
still retains a SE-NW inversion line within its much larger trailing
spot complex. Region 2158 (N15E35, Dkc/beta-gamma-delta), although
relatively quiet recently, appeared to have slight rotation of its
positive leader with penumbral fluctuations along its delta. No
Earth-directed coronal mass ejections were observed during the period.

7th September


Solar wind parameters continued through the period under weak CME
effects. Total field reached a maximum of 12 nT at 06/1531 UTC and
slowly declined to end of period values near 8 nT. The Bz component
deflected southward to a maximum of -7 nT for approximately 9 hours
while solar wind speed increased to a maximum of 431 km/s. By the end
of the period, solar wind speed had decreased to near 340 km/s. Phi
angle was variable in both positive (away) and negative (towards)
sectors during the period.