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Here is this week's space weather and geophysical report, issued 2015 Aug 24 0441 UTC.
Highlights of Solar and Geomagnetic Activity
17 - 23 August 2015
Solar activity ranged from very low to moderate levels. Very low
activity was observed on 17-19 Aug, low level activity on 20 and 23
Aug and moderate level activity on 21-22 Aug. Developing Region 2403
(S15, L=193, class/area Ekc/760 on 23 Aug), which exhibited a
complex beta-gamma-delta magnetic configuration, produced all of the
flare activity during the period.
On 21 Aug, Region 2403 produced three M1 (R1-minor) flares, the
largest was an M1/2b flare observed at 21/0948 UTC. Associated with
this event was a Type II radio emission (estimated 490 km/s shock
velocity) and a partial-halo CME observed off the south limb, first
visible in SOHO/LASCO C2 imagery at 21/1024 UTC. Analysis of this
CME determined that a weak Earth-directed component was present.
22 Aug saw 2 more M-class flares produced by Region 2403, the
largest was an M3/1b flare observed at 22/2124 UTC. Early on the
22nd, the region produced an M1/1b flare observed at 22/0649 UTC.
Associated with this event was a Type II radio emission (estimated
1149 km/s shock velocity), a Type IV radio emission and a
partial-halo CME observed off the NE limb, first visible in
SOHO/LASCO C2 imagery at 22/0712 UTC. Analysis of this CME
determined that a weak Earth-directed component was present.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels on 17-22 Aug with a peak flux of 9,116 pfu observed at
21/1830 UTC. Moderate levels were observed on 23 Aug.
Geomagnetic field activity generally ranged from quiet to active
levels during the period. Isolated minor storm (G1-minor) periods
were observed midday on 17 Aug and again on 23 Aug. An isolated
major storm (G2-moderate) period was observed between 0600-0900 UTC
on 23 Aug. From 17-20 Aug, field conditions ranged from quiet to
minor storm levels and were influenced by a geoeffective positive
polarity coronal hole high speed stream (CH HSS). During this time
frame, measurements at the ACE satellite indicated peak wind speeds
approaching 600 km/s midday on 17 Aug. However, ACE parameters
indicated a fairly weak magnetic structure was present with Bz
measuring a maximum southward extent of only -7 nT. Quiet to
unsettled conditions were present for 21-22 Aug.
By 23 Aug, field conditions increased to unsettled to major storm
levels under the influence of a co-rotating interaction region (CIR)
in advance of an equatorial, positive polarity CH HSS. At about
23/0600 UTC, solar wind parameters observed an increase in wind
speeds from about 400 km/s to near 550 km/s by about 23/0900 UTC.
Wind speeds further increased to 610 km/s by 23/1400 UTC before
ending the period near 525 km/s. IMF total field registered maximum
readings of 15 nT at about 23/0700 UTC while the Bz component
reached a maximum southward extent of -12 nT at about 23/0600 UTC.
The phi angle remained in a predominately positive (away)
orientation throughout the summary period.
Forecast of Solar and Geomagnetic Activity
24 August - 19 September 2015
Solar activity is likely to be at moderate levels (R1-R2,
minor-moderate), with a slight chance for X-class flares (R3-Strong
or greater), from 24-29 August due to the flare potential from
Region 2403. Very low to low flare activity is expected from 30 Aug
to 10 Sep after Region 2403 rotates off the visible disk. A return
to moderate levels (R1-R2, minor-moderate), with a slight chance for
X-class flares (R3-Strong or greater), is likely from 11-19 Sep
after the return of old Region 2403 (S15, L=193).
No proton events are expected at geosynchronous orbit barring any
significant flare activity from Region 2403.
The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at moderate to high levels throughout the period.
Moderate levels are expected on 24 Aug, 27 Aug, 01-04 Sep, 09-12 Sep
and 19 Sep. High levels are expected from 25-26 Aug, 28-31 Aug,
05-08 Sep and 13-18 Sep.
Geomagnetic field activity is expected to be at G1 (minor) on 24 Aug
due to effects from the 21 and 22 Aug CMEs coupled with a positive
polarity CH HSS. G1 (minor) field activity is also expected on 03
Sep due to a positive polarity CH HSS. Unsettled to active levels
are expected on 25-29 Aug, 02 Sep, 04-06 Sep, 12-14 Sep, 16 Sep and
27 Sep due to recurrent CH HSS influences. Quiet to unsettled levels
are expected for the remainder of the outlook period.
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![Weekly Propagation Summary - 2015 Aug 24 16:10 UTC]()
Live data and images: SunSpotWatch.com
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