[Ips-dsgr] ASWFC Daily Report - 01 September 25 issued 2331 UT on 01 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Sep 2 09:31:04 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/01 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 01 SEPTEMBER AND FORECAST FOR 02 SEPTEMBER - 04 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 01 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 01 Sep: 202/153
1B. SOLAR FORECAST
02 Sep 03 Sep 04 Sep
Activity R1, chance R2 R1, chance R2 R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 205/156 200/152 195/147
COMMENT: Solar activity on UT day 01-Sep was at the R0 level,
with no significant flaring activity. There are currently ten
numbered sunspot regions visible on the solar disk and one unnumbered
region. AR4197 (S18W50, beta-gamma) is the most magnetically
complex region on the disk and has decayed over the UT day whilst
remaining flare quiet. AR4199 (N04W35, beta) has exhibited mild
growth in its trailer spots. AR4207 (N30E35, beta) has shown
slight development in its intermediate spots. AR4191 (N11W79,
beta) has shown decay and will soon rotate over the western limb.
An unnumbered region recently appeared near N16E24 (beta) and
has shown mild spot growth. All other sunspot regions are either
stable or in decay. Solar activity is expected to be at the R1
level over 02-04 Sep, with a chance of R2. S0 solar proton conditions
were observed on UT day 01-Sep, though the proton flux was elevated
over the UT day. S0 solar proton conditions are expected over
02-04 Sep. No Earth-directed CMEs have been observed. The solar
wind speed on UT day 01-Sep increased, ranging from 375 to 670
km/s and is currently near 600 km/s. A strong shock was observed
in the solar wind at 01/2027UT, indicative of the arrival of
a halo CME first observed on 30-Aug. A subsequent weak sudden
impulse (45nT) was detected in BOM magnetometer data at 01/2059UT,
indicative of the CME arrival at Earth. The peak total interplanetary
magnetic field strength (IMF, Bt) was 26 nT and the north-south
IMF component (Bz) range was -14 to +15 nT. The solar wind speed
is expected to remain elevated over 02-04 Sep due to ongoing
CME effects.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 01 Sep: G1
Estimated Indices 01 Sep : A K
Australian Region 10 12100235
Cocos Island 7 11110234
Darwin 12 22110245
Townsville 12 22110245
Learmonth 15 22110236
Alice Springs 10 12100235
Gingin 10 22100235
Canberra 8 12000125
Kennaook Cape Grim 6 11101124
Hobart 9 11101225
Estimated Antarctic Regional K Indices 01 Sep :
Macquarie Island 4 01001014
Casey 22 34421236
Mawson 34 42220267
Observed Regional daily pc3 Indices 01 Sep :
Darwin 8 (Quiet)
Townsville 7 (Quiet)
Learmonth 4 (Quiet)
Alice Springs 6 (Quiet)
Gingin 9 (Quiet)
Canberra 34 (Quiet to unsettled)
Hobart 49 (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 01 Sep : A
Fredericksburg 14
Planetary 20
Observed AFr/Ap Indices 31 Aug : A K
Fredericksburg 9 2213 3222
Planetary 8 2213 2222
2B. MAGNETIC FORECAST
Date Ap Conditions
02 Sep 50 G2-G3
03 Sep 18 G0-G1
04 Sep 10 G0
COMMENT: ASWFC Geomagnetic Warning 62 was issued on 31 August
and is current for 1-2 Sep. G1 geomagnetic conditions were observed
in the Australian region on UT day 01-Sep, with an isolated period
of G2 observed at Learmonth. Mostly G2 geomagnetic conditions
were observed in the Antarctic region, with an isolated period
of G3 observed at Mawson. Geomagnetic activity late in the UT
day was due to the arrival of a halo CME first observed on 30-Aug.
G2-G3 geomagnetic conditions are expected on 02-Sep due to ongoing
CME effects. G0-G1 geomagnetic conditions are expected on 03-Sep
as CME effects abate. G0 geomagnetic conditions are expected
on 04-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
01 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
02 Sep Poor Poor Poor
03 Sep Normal Normal-fair Fair
04 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 01-Sep were
mostly normal. HF radio propagation conditions on UT day 02-Sep
are expected to be poor due to current geomagnetic activity.
Conditions are expected to be normal to fair over 03-04 Sep.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
01 Sep 126
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 45% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 60% during local night.
Southern Australian Region:
Enhanced by 15% during local day.
Enhanced by 20% during local night.
Enhanced by 20% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 15% 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
02 Sep 90 Near predicted monthly values
03 Sep 100 Near predicted monthly values
04 Sep 110 Near to 15% above predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 79 was issued
on 31 August and is current for 2-3 Sep. ASWFC SWF HF Communications
Warning 80 was issued on 31 August and is current for 1-2 Sep.
Maximum usable frequencies (MUFs) in the Australian region on
UT day 01-Sep were near predicted monthly values to 15-60% enhanced.
Spread F was observed at Hobart during local night hours. Ionospheric
scintillation was observed at Niue over the interval 01/0822-0840UT.
Current geomagnetic activity is expected to reduce the observed
MUF enhancements to near predicted monthly values over 02-03
Sep. MUFs are expected to be near predicted monthly values to
15% enhanced on 04-Sep. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 31 Aug
Daily Proton Fluence >1 MeV: 3.4E+06
Daily Proton Fluence >10 MeV: 6.8E+04
Daily Electron Fluence >2 MeV: 1.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 31 Aug
Speed: 426 km/sec Density: 3.6 p/cc Temp: 116000 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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