[Ips-dsgr] ASWFC Daily Report - 31 August 25 issued 2331 UT on 31 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon Sep 1 09:31:01 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/31 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 31 AUGUST AND FORECAST FOR 01 SEPTEMBER - 03 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 31 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 31 Aug: 217/167
1B. SOLAR FORECAST
01 Sep 02 Sep 03 Sep
Activity R1, chance R2 R1, chance R2 R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 215/165 210/161 200/152
COMMENT: Solar activity on UT day 31-Aug was R0 with no solar
flares. There are currently ten numbered sunspot on the solar
disk. Sunspot region AR4197 (S18W34, beta-gamma-delta) remains
the most dominant spot, although has been quiet in the past 24
hours. The tail region is showing some decay however there is
still a weak delta spot present. AR4202 (S15W19, beta) has grown
with leader spots developing. Solar activity is expected to be
R1 with a chance of R2 over 1-3 Aug.
On UT day 31-Aug no Earth-directed CMEs were observed in the imagery.
On UT day 31-Aug S0 solar radiation storm conditions were observed,
however the >10 MeV protons remain slightly enhanced. S0 solar
radiation storm conditions are expected.
The solar wind environment on UT day 31-Aug on generally steady.
The solar wind speed ranged from 350 to 498 km/s, with some brief
enhancements from a small coronal hole. The peak total interplanetary
field strength (IMF, Bt) was 10 nT and the north-south IMF component
(Bz) was +9 to -7 nT. The solar wind is expected to become disturbed
either late on 1-Sep UT day or else early 2-Sep due to a CME that
launched from the Sun on 30-Aug. The solar wind is likely to begin
returning to near background levels late on UT day 2-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 31 Aug: G0
Estimated Indices 31 Aug : A K
Australian Region 4 22111111
Cocos Island 3 22110110
Darwin 6 22221212
Townsville 6 22121222
Learmonth 4 22111210
Alice Springs 5 22111212
Gingin 3 22110110
Canberra 3 22111101
Kennaook Cape Grim 3 12111101
Hobart 3 12111101
Estimated Antarctic Regional K Indices 31 Aug :
Macquarie Island 1 11010000
Casey 16 45431112
Mawson 9 23221124
Observed Regional daily pc3 Indices 31 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 8 (Quiet)
Hobart 24 (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 31 Aug : A
Fredericksburg 7
Planetary 10
Observed AFr/Ap Indices 30 Aug : A K
Fredericksburg 8
Planetary 8 2122 2222
2B. MAGNETIC FORECAST
Date Ap Conditions
01 Sep 20 G0-G2
02 Sep 40 G3, slight chance of G4
03 Sep 16 G0-G1
COMMENT: ASWFC Geomagnetic Warning 62 was issued on 31 August
and is current for 1-2 Sep. On UT day 31-Aug G0 geomagnetic conditions
were observed in the Australian region. G0-G1 geomagnetic conditions
were observed in the Antarctic region. On UT day 1-Sep geomagnetic
conditions are expected to be initially G0, but due to an anticipated
CME arrival either late 1-Sep or else early 2-Sep G3 geomagnetic
conditions will be expected. There may be a slight chance for
isolated periods of G4. G3 geomagnetic conditions are expected
for the first half of 2-Sep before trending to G0 conditions.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
31 Aug Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
01 Sep Normal-fair Normal-fair Fair
02 Sep Fair Normal-fair Fair-poor
03 Sep Normal-fair Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 31-Aug were
normal. HF radio propagation conditions on UT day 1-Sep are expected
to become degraded late in the day due to an anticipated CME
arrival. Conditions are expected to remain degraded on UT day
2-Sep. Conditions are likely to begin recovering on 3-Sep.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
31 Aug 122
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Near predicted monthly values 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 15% during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Jul 88
Aug 96
Sep 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
01 Sep 100 Near predicted monthly values to 20% enhanced
02 Sep 90 Near predicted monthly values to 20% depressed
03 Sep 95 Near predicted monthly values to 20% depressed
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 31-Aug were near predicted valued to 20% enhanced.
Spread-F was observed in Hobart during local dawn hours. Scintillation
was observed at Niue from 08:25 to 08:40 UT. Conditions were
briefly degraded at Norfolk Island during local dusk hours. MUFs
are expected to be normal to 20% enhanced until the CME arrival
late on 1-Sep or early 2-Sep. MUFs may become depressed up to
20% afterwards over 2-3 Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 30 Aug
Daily Proton Fluence >1 MeV: 7.3E+06
Daily Proton Fluence >10 MeV: 1.5E+05
Daily Electron Fluence >2 MeV: 1.30E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 30 Aug
Speed: 377 km/sec Density: 2.8 p/cc Temp: 76300 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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