[Ips-dsgr] ASWFC Daily Report - 05 September 26 issued 2330 UT on 05 Sep 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Sep 6 09:30:51 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/05 SEPTEMBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 05 SEPTEMBER AND FORECAST FOR 06 SEPTEMBER - 08 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 05 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.0 1518UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 05 Sep: 111/62
1B. SOLAR FORECAST
06 Sep 07 Sep 08 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 108/58 105/54 105/54
COMMENT: Solar activity on UT day 05-Sep was at the R1 level,
due to an M1.0 flare at 05/1518UT. Two high C-class flares were
also observed, a C6.5 flare at 05/1046UT and a C8.6 flare at
05/1746UT. There are currently seven numbered sunspot regions
visible on the solar disk, although several are very small at
time of writing, and three unnumbered regions. Active region
(AR) 4520 (S12W72, beta) was responsible for the M1.0 flare,
despite almost decaying to plage. AR 4524 (N12E41, beta-gamma)
was responsible for the two high C-class flares of the day and
showed development in its leaders spot. AR 4526 (S03E55, beta)
showed some slight development but remains very small. All other
numbered regions are either stable or in decay. An unnumbered
region has developed on the solar disk at around S10E60 with
beta magnetic characteristics. Two other unnumbered regions have
recently rotated on to the solar disk at around N11E77 and S11E80,
both with apparent alpha magnetic characteristics. Solar activity
is expected to be at R0-R1 levels over 06-08 Sep, due to recent
flare activity from ARs 4520 and 4524. S1 solar radiation storm
conditions were observed on UT day 05-Sep. This was due the M1.0
flare produced by AR 4520 on the western limb. The >10 MeV proton
flux as measured at GOES declined to below the S1 threshold on
05-Sep. S0-S1 conditions are expected on 06-Sep due to enhanced
>10 MeV proton conditions. S0 conditions with a chance of S1
are expected over 07-08 Sep. No significantly geoeffective CMEs
were observed on 05-Sep. Each of the noted flares of the UT day
produced an associated CME. The largest flare, the M1.0 flare
at 05/1518UT produced a west directed CME, first observed in
SOHO and STEREO-A imagery at 05/1536UT. Modelling suggests this
CME will pass ahead of the Earth and will impact STEREO-A at
0300UT on 08-Sep +/- 8 hours. The two high C-class flares produced
narrow east directed CMEs, first observed in SOHO and STEREO-A
imagery from 05/1112UT and 05/1800UT. Modelling suggests both
will pass behind the Earth, with the possibility of a glancing
impact on 08-Sep at 1400UT +/- 12 hours. Analysis is ongoing
for the possible combined effects of these CMEs. The solar wind
environment on UT day 05-Sep was at background levels. The solar
wind speed mostly ranged between 320 and 370 km/s and is currently
at around 355 km/s. The peak total interplanetary field strength
(IMF, Bt) was 8 nT and the north-south IMF component range was
+5 to -5 nT. A mild increase in the solar wind speed is expected
on 06-Sep due to an equatorial coronal hole rotating towards
a geoeffective position. This increase is expected to continue
on 07-Sep. A further increase is possible on 08-Sep due to anticipated
glancing CME impacts.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 05 Sep: Quiet
Estimated Indices 05 Sep : A K
Australian Region 3 22221000
Cocos Island 2 12120000
Darwin 4 22221001
Townsville 4 22221011
Learmonth 3 22221000
Alice Springs 4 22221001
Gingin 3 22221000
Canberra 3 22120000
Kennaook Cape Grim 3 22220000
Hobart 3 22220000
Estimated Antarctic Regional K Indices 05 Sep :
Macquarie Island 4 12230000
Casey 6 33222001
Mawson 9 24422001
Observed Regional daily pc3 Indices 05 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 0 (Quiet)
Pc3 pulsations are high frequency (10-45 second period) variations
of the Earths magnetic field. Daily pc3-indices are the daily sum
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data.
NOTE: Indices may have been generated from data obtained in
cooperation with the following organisations: Geoscience Australia,
University of Newcastle Space Physics Group, Australian Government
Antarctic Division and International Center for Space Weather
Science and Education, Japan.
Estimated AFr/Ap Indices 05 Sep : A
Fredericksburg 8
Planetary 8
Observed AFr/Ap Indices 04 Sep : A K
Fredericksburg 4
Planetary 4 1112 1010
2B. MAGNETIC FORECAST
Date Ap Conditions
06 Sep 8 G0
07 Sep 8 G0
08 Sep 12 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed at the planetary
level and in the Australian and Antarctic regions on UT day 05-Sep.
G0 geomagnetic conditions are expected over 06-07 Sep. G0 conditions,
with a chance of G1, are expected on 08-Sep due to a combination
of high speed wind stream effects and a pair of potential glancing
CME impacts.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
05 Sep Normal Normal Normal-fair
PCA Event : 10MeV Proton/PCA Event Began at 1610UT 05/09, Ended at 2110UT 05/09
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
06 Sep Normal Normal Normal-fair
07 Sep Normal Normal Normal-fair
08 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 04-Sep were
mostly normal, with some mild degradations around the equator
during local night hours. HF radio propagation conditions are
expected to be similar to recent conditions over 05-07 Sep, with
the possibility of minor degradations at high latitudes on 07-Sep
due to possible geomagnetic activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
05 Sep 64
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Depressed by 15% during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 66
Sep 62
Oct 60
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
06 Sep 65 Near predicted monthly values
07 Sep 65 Near predicted monthly values
08 Sep 65 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region were near predicted monthly values over 05-Sep. MUFs are
expected to be mostly near predicted values over 05-07 Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 04 Sep
Daily Proton Fluence >1 MeV: 4.5E+05
Daily Proton Fluence >10 MeV: 2.1E+04
Daily Electron Fluence >2 MeV: 6.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 8%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.6
Solar Wind Day Averaged Data for 04 Sep
Speed: 372 km/sec Density: 3.2 p/cc Temp: 90000 K Bz: 1 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
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