[Ips-dsgr] ASWFC Daily Report - 05 September 25 issued 2330 UT on 05 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Sep 6 09:30:57 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/05 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 05 SEPTEMBER AND FORECAST FOR 06 SEPTEMBER - 08 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** 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
M1.4 0116UT possible lower West Pacific
Observed 10.7 cm flux/Equivalent Sunspot Number for 05 Sep: 149/104
1B. SOLAR FORECAST
06 Sep 07 Sep 08 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 140/94 138/92
COMMENT: Solar activity on UT day 05-Sep was at the R1 level
due to an M1.4 flare from AR4207 (N31E01, beta-gamma). This medium
sized solar region is currently the largest and most magnetically
complex region on the solar disk and is showing decay in its
trailer spots. Solar region AR4197 (S18W87, beta) which was a
recent region of interest showed decay as it rotated off the
visible solar disk. Most of the on disk solar regions are relatively
small. There are currently nine numbered sunspot regions visible
on the solar disk. All other sunspot regions are either stable
or in decay. Solar activity is expected to be at the R0-R1 level
over 06-08 Sep. S0 solar radiation storm conditions were observed
on UT day 05-Sep. S0 solar radiation storm conditions are expected
over 06-08 Sep. Two solar filament eruptions have recently been
observed. A small north south orientated 8 degree long filament
located at N10W05 erupted at 04/1912 with narrow southward and
later southeast directed plasma motion visible in SDO304 imagery
from 04/1937UT. A minor southwest CME was observed in LASCO C2
first visible from 04/1812UT. As this CME precedes the time of
the small filament eruption it has not been paired to this event.
A very faint CME was observed in LASCO C2 to the southeast from
04/1948UT and a narrow south directed CME was observed from 04/2200UT.
These CMEs match the dark southward and partial east directed
plasma motion visible in SDO304 imagery and have been paired
to the small filament eruption. The narrow southward CME is not
considered to be significantly Earth directed as it is predominately
directed southward out of the ecliptic plane and is too narrow
to model. The very faint southeast component of the CME has been
modelled and may arrive at the Earth on 07-Sep at 1000UT +/-
12 hours, though modelling indicates most of the CME will pass
behind the Earth. A 22 degree long east west orientated solar
filament with centre located at N18E25 partially lifted off from
05/0434UT visible in GONG H-alpha imagery. No significant CME
appeared to follow this larger slower partial filament eruption
on 05-Sep. A north-northwest CME was also observed from 05/0136UT,
directed northward out of the ecliptic plane. A broad coronal
hole spans across the solar disk in the southern solar hemisphere.
The solar wind speed on UT day 05-Sep was steady and slightly
elevated, ranging from 387 to 488 km/s and is currently near
405 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 10 nT and the north-south IMF component (Bz) range
was -7 to +7 nT. The solar wind speed is expected to increase
over 06-07 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 05 Sep: G0
Estimated Indices 05 Sep : A K
Australian Region 4 11121122
Cocos Island 4 11121022
Darwin 5 11121123
Townsville 5 11121123
Learmonth 6 21121132
Alice Springs 4 11121022
Gingin 5 21120132
Canberra 4 10121122
Kennaook Cape Grim 4 11121122
Hobart 4 11121122
Estimated Antarctic Regional K Indices 05 Sep :
Macquarie Island 4 00041111
Casey 11 33322133
Mawson 34 32223276
Observed Regional daily pc3 Indices 05 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 8 (Quiet)
Hobart 7 (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 11
Planetary 14
Observed AFr/Ap Indices 04 Sep : A K
Fredericksburg 10
Planetary 10 2123 2323
2B. MAGNETIC FORECAST
Date Ap Conditions
06 Sep 15 G0-G1
07 Sep 20 G1
08 Sep 15 G0-G1
COMMENT: ASWFC Geomagnetic Warning 64 was issued on 5 September
and is current for 6-7 Sep. G0 geomagnetic conditions were observed
in the Australian region on UT day 05-Sep. In the Antarctic region
G0 geomagnetic conditions were observed at Macquarie Island and
Casey with an isolated G3 period at Mawson. G0-G1 geomagnetic
conditions are generally expected on 06-08 Sep due to a solar
coronal hole wind stream, with G1 periods expected for the second
half of the UT day on 07-Sep due to a CME glancing blow from
a recent small solar filament eruption.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
05 Sep Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
06 Sep Normal Fair-normal Fair
07 Sep Normal Fair-normal Fair
08 Sep Normal Fair-normal Fair
COMMENT: HF radio propagation conditions on UT day 05-Sep were
fair to normal. HF radio propagation conditions are generally
expected to be mildly degraded at middle to high latitudes over
06-08 Sep. HF conditions may be moderately degraded at middle
to high latitudes from the second half of the UT day 07-Sep due
to a possible weak CME arrival. Isolated minor shortwave fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
05 Sep 114
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 30% during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% 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
06 Sep 100 Near predicted monthly values
07 Sep 100 Near predicted monthly values
08 Sep 80 15% depressed to near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the northern Australian
region on UT day 05-Sep were near predicted monthly values to
30% enhanced. Enhanced MUFs were observed during local night
hours. Spread F was observed at Hobart during local night hours.
MUFs are generally expected to be near to predicted monthly values
over 06-08 Sep with degraded HF conditions during local night
hours for the southern Australian region. Mild depressions of
15% may be experienced after local dawn for the southern Australian
region. MUFs for the southern Australian region may become 15%
depressed on 08-Sep due to a possible weak CME arrival on 07-Sep.
Isolated minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 04 Sep
Daily Proton Fluence >1 MeV: 1.4E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 04 Sep
Speed: 463 km/sec Density: 0.7 p/cc Temp: 109000 K Bz: -2 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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