[Ips-dsgr] ASWFC Daily Report - 24 September 26 issued 2332 UT on 24 Sep 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Sep 25 09:32:28 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 SEPTEMBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 24 SEPTEMBER AND FORECAST FOR 25 SEPTEMBER - 27 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 24 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Sep: 112/63
1B. SOLAR FORECAST
25 Sep 26 Sep 27 Sep
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 110/60 110/60 105/54
COMMENT: Solar flare activity on UT day 24-Sep was at the R0
level, with only a low-level C-class flare observed. There are
currently eight numbered sunspot regions visible on the solar
disk. Active region (AR) 4536 (N03W38, beta) is currently the
largest region however has remained stable over the past UT day.
All other sunspot regions are either stable or in decay. Solar
flare activity is expected to be at the R0 level over 25-27 Sep.
Solar radiation storm conditions were at the S0 level on 24-Sep,
with the solar proton flux at background levels. S0 solar radiation
storm conditions are forecast over 25-27 Sep. No Earth-directed
coronal mass ejections (CMEs) were observed over the past UT
day. A southwest-directed CME was observed, visible in coronagraph
imagery from 24/0336UT. Modelling indicates this CME does not
contain an Earth-directed component. The solar wind speed on
UT day 24-Sep increased, ranging from 300 to 450 km/s, and is
currently near 445 km/s. The peak total interplanetary magnetic
field strength (IMF, Bt) was 15 nT. The north-south component
(Bz) ranged between -13 and +9 nT over the same period. Sustained
periods of southward IMF conditions were observed over the intervals
24/0349-0905UT and 24/1025-2101UT. The solar wind speed is expected
to remain elevated over 25-27 Sep due to ongoing coronal hole
high speed wind stream effects from a southern coronal hole before
entering another high speed wind stream from a northern hemisphere
coronal hole over 26-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 24 Sep: G0
Estimated Indices 24 Sep : A K
Australian Region 12 22343322
Cocos Island 9 22233321
Darwin 12 22243323
Townsville 14 32343323
Learmonth 15 22343423
Alice Springs 12 22343322
Gingin 13 22343323
Canberra 10 22332322
Kennaook Cape Grim 11 22342322
Hobart 12 22343322
Estimated Antarctic Regional K Indices 24 Sep :
Casey 15 34342223
Mawson 22 43434344
Observed Regional daily pc3 Indices 24 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 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 24 Sep : A
Fredericksburg 15
Planetary 20
Observed AFr/Ap Indices 23 Sep : A K
Fredericksburg 4
Planetary 4 0001 1122
2B. MAGNETIC FORECAST
Date Ap Conditions
25 Sep 10 G0
26 Sep 12 G0, chance G1
27 Sep 8 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
and Antarctic regions on UT day 24-Sep, with G0 geomagnetic conditions
also recorded at the planetary scale. G0 geomagnetic conditions
are expected over 25-27 Sep, with chance of G1 on 26-Sep due
to a northern hemisphere coronal hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
24 Sep Normal Normal Normal-fair
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-fair
27 Sep Normal Normal Normal-fair
COMMENT: Global high-frequency (HF) radio propagation conditions
on the 24-Sep was mostly normal, with some normal-fair conditions
observed in high latitude regions. Global HF conditions are expected
to be mostly normal over 25-27 Sep with a continuation of normal-fair
conditions at high latitudes due to further anticipated geomagnetic
activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
24 Sep 76
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.
Near predicted monthly values during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 45% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 66
Sep 62
Oct 60
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
25 Sep 70 Near predicted monthly values
26 Sep 60 Near predicted monthly values
27 Sep 65 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region were mostly near predicted monthly values over UT day
24-Sep with enhancements of 25-45% during local night. MUFs are
forecast to be near predicted monthly values over 25-27 Sep.
While depressions are expected due to further anticipated geomagnetic
activity, current MUFs are already elevated above predicted monthly
values.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 23 Sep
Daily Proton Fluence >1 MeV: 1.4E+06
Daily Proton Fluence >10 MeV: 2.1E+04
Daily Electron Fluence >2 MeV: 3.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B5.2
Solar Wind Day Averaged Data for 23 Sep
Speed: 287 km/sec Density: 5.0 p/cc Temp: 36900 K Bz: 3 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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