[Ips-dsgr] ASWFC Daily Report - 24 September 25 issued 2330 UT on 24 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Sep 25 09:30:48 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 24 SEPTEMBER AND FORECAST FOR 25 SEPTEMBER - 27 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 24 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.0 0931UT possible lower Mid East/Indian
M1.6 1913UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Sep: 184/137
1B. SOLAR FORECAST
25 Sep 26 Sep 27 Sep
Activity R0 change R1 R0 change R1 R0 change R1
Fadeouts Possible Possible Possible
10.7cm/SSN 170/124 170/124 165/119
COMMENT: Solar activity on UT day 24-Sep was at the R1 level.
There are currently nine numbered sunspot regions on the solar
disk and one unnumbered region near south east of AR4229. AR4217
(S16W60, beta-gamma) is the most magnetically complex region
on the disk and has shown growth in its intermediates. This region
has produced two M-class flares with the largest being M1.6 flare
over the UT day. AR4226 (S11E20, beta-gamma), AR4225 (N10W26,
beta), AR4229 (S04W44, beta), AR4230 (S11E46, beta) and are
showing growth in their intermediates. All other solar regions
are either stable or in decay. Solar activity is expected to
be at the R0 level with a chance of R1 over 25-27 Sep. No Earth-directed
CMEs have been observed. S0 solar radiation storm conditions
were observed on UT day 24-Sep. S0 solar radiation storm conditions
are expected over 25-27 Sep. Two small sized coronal holes are
currently passing the central meridian and may increase the solar
wind late 27-Sept. Solar wind speed on UT day 24-Sep ranged from
485 km/s to 472 km/s and is currently at 499 km/s. The peak total
interplanetary field strength (IMF, Bt) was 7 nT and the north-south
IMF component (Bz) range was +5 to -3 nT. The solar wind is expected
to remain steady with a slight increase late on 27-Sept as the
small coronal hole becomes geoeffective.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 24 Sep: G0
Estimated Indices 24 Sep : A K
Australian Region 6 11123212
Cocos Island 4 12112111
Darwin 7 21123213
Townsville 7 21023213
Learmonth 6 11123212
Alice Springs 5 11113212
Gingin 7 22123222
Canberra 5 11023202
Kennaook Cape Grim 5 11023202
Hobart 5 11123202
Estimated Antarctic Regional K Indices 24 Sep :
Macquarie Island 7 11034201
Casey 15 34433222
Mawson 18 23323216
Observed Regional daily pc3 Indices 24 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 24 (Quiet to unsettled)
Canberra 24 (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 24 Sep : A
Fredericksburg 6
Planetary 6
Observed AFr/Ap Indices 23 Sep : A K
Fredericksburg 12
Planetary 14 3333 4332
2B. MAGNETIC FORECAST
Date Ap Conditions
25 Sep 8 G0
26 Sep 5 G0
27 Sep 10 G0 Chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 24-Sep. In the Antarctic region G0-G1 geomagnetic
conditions were observed. G0 conditions are expected on 25-26
Sept. G0 with a chance of G1 are expected on 27 Sep due to coronal
hole wind stream influence.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
24 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
25 Sep Normal Normal Normal-fair
26 Sep Normal Normal Normal
27 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 24-Sep were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 25-27 Sep. Isolated minor shortwave fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
24 Sep 127
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Enhanced by 100% during local night.
Niue Island Region:
Enhanced by 40% during local day.
Enhanced by 35% during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Enhanced by 30% after local dawn.
Southern Australian Region:
Mostly near predicted monthly values.
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
25 Sep 115 Near to 15% above predicted monthly values
26 Sep 110 Near to 15% above predicted monthly values
27 Sep 100 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 24-Sep were near predicted values to 15% enhanced.
Spread F was observed at Hobart over local night. MUFs are expected
to be near predicted values to enhanced by 15% over 25-27 Sep.
Isolated minor shortwave fadeouts are possible. Equatorial scintillation
possible over 25-27 Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 23 Sep
Daily Proton Fluence >1 MeV: 6.4E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.70E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 23 Sep
Speed: 553 km/sec Density: 0.1 p/cc Temp: 174000 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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