Solar activity summary (Last 24 hours)

21st August


Solar activity was low. Several C-level flares were produced by a
region just beginning to rotate onto the disk in the northeast near 12N,
including the largest of the period, a C4 event at 20/1251 UTC and a C1

Region 2146 (N10E14, Cso/beta) grew during the period and was also
responsible for two notable events. The first was a C2/Sf flare at
20/2157 UTC. This event was accompanied by a darkening to the west and
south in SDO/AIA 193 imagery. At 20/2348 UTC, a very faint CME was
observed emerging from the east limb in SOHO/LASCO C2 imagery with an
approximate plane of sky speed of 200-300 km/s. The second event was a
B8/Sf flare from the same region at 21/0855 UTC. Another darkening and
westward propagating wave was evident in SDO/AIA 193 imagery at 21/0848
UTC. Subsequent coronagraph imagery has not yet been received.

Regions 2148 (N05E34, Dac/beta) and 2143 (S06W33, Dai/beta) also grew
during the period, and Region 2148 was responsible for three low-level
C-flares.

The remaining regions were stable or decaying. Additional analysis of
coronagraph imagery, and modeling if possible, will be undertaken to
ascertain any threat from the events described above.

20th August


Solar activity was low. The largest flare of the period was a C1/Sf at
19/2331 UTC from newly numbered Region 2148 (N06E48, Dro/beta), which
emerged rapidly during the period. Region 2147 produced a B9/1F flare
at 20/0010 UTC but remained stable. Regions 2146 (N08E42, Hsx/alpha)
and 2143 (S04W05, Dri/beta) both developed slightly during the period
while the remaining regions were stable or decaying. Another C1 flare
was observed at 20/0914 UTC from a region beyond the northeast limb. No
Earth-directed eruptions were noted.

19th August


Solar activity was low. Regions 2147 (S09E53, Hax/Alpha) and Region 2139
(N14W40, Cao/Beta) produced C1/Sf flares at 19/1355 UTC and 19/1656 UTC
respectively. Both regions decayed during the period, but Region 2147
had produced a B8/Sf flare as late as 19/0648 UTC. Region 2143 was the
only one to grow during the period, with several intermediate spots
emerging. No Earth-directed coronal mass ejections (CMEs) were observed
in coronagraph imagery.

18th August


Solar activity was low. A single C1 flare, observed at 17/1948 UTC from
Region 2146 (N10E54, Hax/alpha), was the largest solar event of the
period. Region 2144 (S17W67, Dao/beta) produced a few B-class events and
displayed signs of intermediate spot decay along with magnetic
simplification. Region 2139 (N14W18, Cai/beta) exhibited decay in
trailer spots along with magnetic simplification as well. The remaining
three numbered sunspots were absent of significant flare activity and
appeared stable. There were no Earth-directed coronal mass ejections
(CMEs) observed in satellite imagery.

17th August


Solar activity declined to very low levels with a few B-class flares
observed. Region 2139 (N14W04, Eac/beta-gamma) produced a B8/Sf at
17/0020 UTC. Little change was noted in this region. Region 2144
(S17W54, Dsi/beta-gamma) produced a C8/Sf at 17/0704 UTC. The region
showed some growth in both its large leader and trailer spots. The
remaining five spotted groups were stable and unremarkable. No Earth
directed coronal mass ejections (CMEs) were detected.

16th August


Solar activity was at low levels. Multiple C-class activity was observed
from Regions 2139 (N14E09, Eac/beta-gamma) and 2144 (S17W42,
Dai/beta-gamma), the largest a C2/Sf at 16/0929 UTC from Region 2144.
Region 2139 showed some intermediate spot consolidation while Region
2144 continued its rapid growth forming mature trailer spot penumbra.
Both of these regions, as well as Region 2141 (N15E40, Dac/beta-gamma),
exhibited increased magnetic complexity over the past 24 hours. New
region 2146 (N10E79, Hax/alpha) rotated onto the disk.

NSO/GONG and SDO/AIA 193 and 304 imagery observed major portions of a
filament erupt along a 30 degree long channel between 15/1630-1715 UTC.
The N/S oriented filament was centered near S06W02 with a majority of
the eruption north of this center point. SDO/AIA 304 imagery observed
material movement to the NNE and SW across the solar disk as a result of
the eruption. A slow-moving, partial-halo coronal mass ejection (CME)
was observed in SOHO/LASCO C2 and C3 imagery at 15/1800 UTC and 15/1906
UTC respectively. CME analysis and subsequent WSA-Enlil model output
suggested an Earth impact late on 18 August. However, further analysis
and adjustments for a slower ambient wind speed is expected to indicate
a later Earth impact closer to midday on the 19th.

15th August


Solar activity remained very low though x-ray background levels
increased over the past 24 hours. The largest event of the period was a
B9/Sf flare at 15/0837 UTC from Region 2139 (N13E23, Eac/beta). Region
2139 showed signs of intermediate and trailer spot consolidation with
increased areal growth and spot count.

Region 2141 (N16E55, Dac/beta) was the most active region producing
numerous B-class events. This region also exhibited the most growth this
period with rapid penumbra development in its leader and trailer spots
coupled with an overall increase in both area and spot count.

Late in the period, Region 2144 (S17W27, Cao/beta) produced a B9/Sf
flare at 15/101 UTC. Since its rapid emergence on the disk late on 14
August, the region has indicated little change.

The remaining numbered sunspot groups were stable. No Earth-directed
coronal mass ejections (CMEs) were observed in satellite imagery.

14th August


Solar activity continued at very low levels with a few B-class flares
observed. The largest event of the period was a B6/Sf at 14/0419 UTC
from Region 2139 (N13E36, Eac/beta). Associated with this event was a
Type II radio sweep (802 km/s shock velocity) reported by both the
Learmonth and Culgoora observatories. Some spot development was noted
within the intermediate portion of the group. The remaining spot groups
exhibited little change.

Three new regions near the east limb were numbered during the period;
Region 2141 (N15E65, Bxo/beta), Region 2142 (N05E60, Axx/alpha) and
Region 2143 (S07E67, Cro/beta). No Earth-directed coronal mass ejections
(CMEs) were observed in satellite imagery.

13th August


Solar activity continued at very low levels. A few nominal B level
enhancements were observed from Regions 2137 (S18W57, Bxo/beta) and 2140
(N13W60, Cao/beta). Region 2139 (N14E48, Dsi/beta-gamma) exhibited
growth in its trailer spots and developed mixed magnetic polarities
within the leader portion of the region. This region remained quiet as
did the other spotted regions on the disk. There were no Earth-directed
coronal mass ejections (CMEs) observed in satellite imagery.

12th August


Solar activity decayed to very low levels. Region 2139 (N14E61,
Dso/beta) produced a B4/Sf flare at 12/0619 UTC. The region continues to
evolve as it rotates more fully onto the disk. New Region 2140 (N13W47,
Bxo/beta) produced a B4/Sf at 12/0657 UTC. The largest group on the
disk, Region 2135 (N12W13, Eao/beta), exhibited some decay in its
trailer spots and remained quiet. The remaining regions on the disk were
inactive and unremarkable. There were no Earth-directed coronal mass
ejections (CMEs) observed in satellite imagery.