[Ips-dsgr] ASWFC Daily Report - 04 September 25 issued 2337 UT on 04 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Sep 5 09:37:25 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/04 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 04 SEPTEMBER AND FORECAST FOR 05 SEPTEMBER - 07 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 04 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.0 1344UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Sep: 172/126
1B. SOLAR FORECAST
05 Sep 06 Sep 07 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 168/122 162/116 158/112
COMMENT: Solar activity on UT day 04-Sep was at the R1 level.
There are currently 11 numbered sunspot regions visible on the
solar disk. AR4207 (N31E14, beta-gamma) is the most magnetically
complex region on the disk that has so far produced a few minor
flares is showing growth on its intermediates. AR4197 (S18W74,
beta) is also showing growth in its intermediate spots. All other
sunspot regions are either stable or in decay. A filament eruption
(N10W05) was observed at 19:12 UT but awaiting more imagery to
see if there was an associated CME. Solar activity is expected
to be at the R0-R1 level over 05-07 Sep. S0 solar proton conditions
were observed on UT day 04-Sep. S0 solar proton conditions are
expected over 05-07 Sep. No other Earth-directed CMEs have been
observed. The solar wind speed on UT day 04 Sep was steady at
around background levels, ranging from 395 to 568 km/s and is
currently near 466 km/s. The peak total interplanetary magnetic
field strength (IMF, Bt) was 8 nT and the north-south IMF component
(Bz) range was -6 to +6 nT. The solar wind speed is expected
to increase over 06-07 as a recurrent southern hemisphere coronal
hole becomes geoeffective.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 04 Sep: G0
Estimated Indices 04 Sep : A K
Australian Region 8 21122323
Cocos Island 6 11121223
Darwin 8 22222223
Townsville 8 21122323
Learmonth 9 21223323
Alice Springs 7 20122323
Gingin 9 20222333
Canberra 7 20122323
Kennaook Cape Grim 9 20133323
Hobart 9 21132323
Estimated Antarctic Regional K Indices 04 Sep :
Macquarie Island 10 10242412
Casey 12 22332324
Mawson 23 12242446
Observed Regional daily pc3 Indices 04 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 2 (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 04 Sep : A
Fredericksburg 8
Planetary 10
Observed AFr/Ap Indices 03 Sep : A K
Fredericksburg 8
Planetary 8 5322 2121
2B. MAGNETIC FORECAST
Date Ap Conditions
05 Sep 14 G0
06 Sep 15 G0-G1
07 Sep 15 G0-G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 04-Sep. G1 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
on 05 Sep. G0-G1 geomagnetic conditions are expected on 06-07
Sep due to a recurrent southern hemisphere coronal hole moving
into a geoeffective position.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
04 Sep Normal Normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
05 Sep Normal Normal Normal-fair
06 Sep Normal Normal Normal-fair
07 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 04-Sep were
mostly normal at low and mid latitudes and fair at high latitudes.
HF conditions are HF radio propagation conditions are expected
to be normal to fair over 05-07 Sep. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
04 Sep 112
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 45% during local night.
Northern Australian Region:
Near predicted monthly values.
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
05 Sep 105 Near predicted monthly values
06 Sep 107 Near predicted monthly values
07 Sep 108 Near to 15% below predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 82 was issued on
3 September and is current for 3-5 Sep. Maximum usable frequencies
(MUFs) in the northern Australian region on UT day 04-Sep were
near predicted monthly values. MUFs in the southern Australian
region near predicted values during local day and near predicted
values during local night. Spread F was observed in Perth during
local night. Sporadic E was observed at Hobart over the UT day.
Scintillation was observed at Niue on UT day 04 Sep starting
at 07:11 and ending on 07:30 UT 04 Sep. MUFs are expected to
be near to predicted monthly values over 05-06 Sep. Near to 15%
depressions are expected on 7 Sep. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 03 Sep
Daily Proton Fluence >1 MeV: 3.3E+06
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.00E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.4
DSCOVR Satellite Solar Wind Day Averaged Data for 03 Sep
Speed: 472 km/sec Density: 1.7 p/cc Temp: 25000 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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