[Ips-dsgr] ASWFC Daily Report - 06 September 25 issued 2330 UT on 06 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Sep 7 09:30:48 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/06 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 06 SEPTEMBER AND FORECAST FOR 07 SEPTEMBER - 09 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 06 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.2 2215UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 06 Sep: 146/100
1B. SOLAR FORECAST
07 Sep 08 Sep 09 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 135/89 130/84
COMMENT: Solar activity on UT day 06-Sep was R1 due to an impulsive
M1.2 flare from solar region AR4207 (N31W11, beta-gamma). Solar
region AR4207 also produced several C class flares and exhibited
a mixture of growth and decay, but this medium sized region appears
to be in overall slow decay. This region produced minor C class
flare activity. During the interval 06/1230-2100UT the background
X-ray flux showed an increase in emission up to the C4 to C5
level which was associated with activity on the solar western
limb, possibly from AR4197 just behind the southwest solar limb.
Smaller solar region AR4213 (S13E22, beta) is growing. Most of
the on disk solar regions are relatively small. There are currently
eight numbered sunspot regions visible on the solar disk. All
other sunspot regions are either stable or in decay. A small
7 degree long solar filament located at N13W26 erupted at 06/1500UT,
visible in GONG H-alpha imagery. In GOES SUVI 195 imagery breaking
arches are visible on the western limb near this time, together
with a small bright emission on the western solar limb at solar
latitude N05 from 06/1532UT. There is solar longitude ambiguity
as to whether the breaking plasma arches are related to the filament
eruption or the small bright emission on the solar western limb
at N05. Solar activity is expected to be at the R0-R1 level over
07-09 Sep. S0 solar radiation storm conditions were observed
on UT day 06-Sep. S0 solar radiation storm conditions are expected
over 07-09 Sep. A broad coronal hole spans across the solar disk
in the southern solar hemisphere, with most of the area of this
hole now west of the solar central meridian. Two notable westward
directed CMEs have been observed. A large southwest CME was observed
in LASCO and STEREO-A imagery from 06/1325UT. This CME has been
associated with activity on the southwest solar limb. Modelling
indicates this slow CME will pass well ahead of the Earth. A
westward CME was observed from 06/1548UT. Using LASCO and STEREO-A
imagery the CME analysis tool shows that the solar longitude
location of the westward CME is most likely associated with the
emission on the northwest limb at N05 rather than the small on
disk filament eruption. Using the northwestern solar limb longitude
location this CME has been modelled as an Earth miss, passing
well ahead of the Earth. The solar wind speed on UT day 06-Sep
slowly increased from the start of the UT day to 06/1230UT due
to the influence of a coronal hole wind stream. The solar wind
parameters then further increased during the interval 06/1230-2100UT,
with Bt increasing to 22 nT and with increased fluctuations and
strength in the IMF Bz component. The solar wind and Bt both
increased and then decreased during this interval. The ACE EPAM
data channel also showed a weak ion enhancement during this interval
which suggests a possible very weak indistinct CME signature
on top of the coronal hole wind stream influence. The solar wind
speed ranged from 403 to 678 km/s and is currently near 590 km/s.
The peak total interplanetary magnetic field strength (IMF, Bt)
was 22 nT and the north-south IMF component (Bz) range was -11
to +10 nT. The solar wind speed is expected to remain elevated
due to the wind stream from the coronal hole located in the southern
solar hemisphere.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 06 Sep: G0
Estimated Indices 06 Sep : A K
Australian Region 15 23334431
Cocos Island 13 23223440
Darwin 15 33333431
Townsville 15 23334431
Learmonth 18 23344441
Alice Springs 14 23333431
Gingin 19 33344441
Canberra 15 23334431
Kennaook Cape Grim 17 23344431
Hobart 20 24344441
Estimated Antarctic Regional K Indices 06 Sep :
Macquarie Island 38 23456651
Casey 22 35443431
Mawson 38 45644632
Observed Regional daily pc3 Indices 06 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 32 (Quiet to unsettled)
Canberra 21 (Quiet to unsettled)
Hobart 25 (Quiet to unsettled)
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 06 Sep : A
Fredericksburg 21
Planetary 29
Observed AFr/Ap Indices 05 Sep : A K
Fredericksburg 8
Planetary 8 2113 1233
2B. MAGNETIC FORECAST
Date Ap Conditions
07 Sep 20 G1
08 Sep 15 G0-G1
09 Sep 12 G0
COMMENT: ASWFC Geomagnetic Warning 65 was issued on 6 September
and is current for 6-8 Sep. G0 geomagnetic conditions were observed
in the Australian region on UT day 06-Sep, with a mild increase
in geomagnetic activity observed. In the Antarctic region G0-G2
geomagnetic conditions were observed. G1 periods are expected on
07-Sep due to a CME glancing blow CME arrival and ongoing coronal
hole wind stream influence. G0-G1 conditions are expected on
08-Sep, with an a gradual decline in geomagnetic activity.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
06 Sep Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
07 Sep Normal Normal-fair Fair
08 Sep Normal Normal Normal-fair
09 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 06-Sep were
fair to normal. HF radio propagation conditions are generally
expected to be mildly degraded at middle to high latitudes on
07-Sep, then improving. Isolated minor shortwave fadeouts are
possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
06 Sep 121
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 35% during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 96
Sep 92
Oct 90
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
07 Sep 90 Depressed 10 to 15%/near predicted monthly values
08 Sep 80 Depressed 10 to 15%/near predicted monthly values
09 Sep 100 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the northern Australian
region on UT day 06-Sep were near predicted monthly values to
20% enhanced. Spread F was observed at Canberra and Hobart during
local night hours. MUFs are generally expected to be 15% depressed
to near to predicted monthly values over 07-08 Sep with degraded
HF conditions during local night hours for the southern Australian
region. MUFs are expected to be near predicted monthly values
on 09-Sep. Isolated minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 05 Sep
Daily Proton Fluence >1 MeV: 8.3E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 2.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 05 Sep
Speed: 407 km/sec Density: 3.5 p/cc Temp: 86000 K Bz: 0 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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