[Ips-dsgr] ASWFC Daily Report - 23 September 25 issued 2330 UT on 23 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Sep 24 09:30:49 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 SEPTEMBER AND FORECAST FOR 24 SEPTEMBER - 26 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.0 1034UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Sep: 171/125
1B. SOLAR FORECAST
24 Sep 25 Sep 26 Sep
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
10.7cm/SSN 168/122 165/119 160/114
COMMENT: Solar activity on UT day 23-Sep was at the R1 level.
There are currently twelve numbered sunspot regions on the solar
disk. Of note, AR4217 (S14W52, beta) was associated with an M1.0
flare on UT day 23-Sep however has shown some decay in leader
and trailer spots. AR4229 (S04W30, beta) has recently emerged
on the solar disk and has shown rapid growth. AR4226 (S11E30,
beta) has shown growth in intermediates. Other solar regions
on the visible solar disk are either stable or in decay. Solar
activity is expected to be at the R0 level with a chance of R1
over 24-26 Sep. No Earth-directed CMEs have been observed. S0
solar radiation storm conditions were observed on UT day 23-Sep.
S0 solar radiation storm conditions are expected over 24-26 Sep.
A moderately sized isolated coronal hole is visible in the northwestern
solar quadrant with centre at approximately N25W55. The solar
wind speed on UT day 23-Sep ranged from 500 km/s to 610 km/s
and is currently at 560 km/s. The peak total interplanetary field
strength (IMF, Bt) was 11 nT and the north-south IMF component
(Bz) range was +7 to -6 nT. The solar wind is expected to gradually
decline throughout the UT day due to coronal hole high speed
wind stream effects easing over 24-26 Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Sep: G0
Estimated Indices 23 Sep : A K
Australian Region 11 32124232
Cocos Island 6 21122231
Darwin 11 32224232
Townsville 11 32124232
Learmonth 11 32224232
Alice Springs 9 22124231
Gingin 13 32224341
Canberra 9 22124222
Kennaook Cape Grim 12 32124332
Hobart 10 22124322
Estimated Antarctic Regional K Indices 23 Sep :
Macquarie Island 21 22236521
Casey 19 44434232
Mawson 30 53344355
Observed Regional daily pc3 Indices 23 Sep :
Darwin 2 (Quiet)
Townsville 0 (Quiet)
Learmonth 15 (Quiet)
Alice Springs 2 (Quiet)
Gingin 83 (Minor storm)
Canberra 71 (Active)
Hobart 106 (Major storm)
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 23 Sep : A
Fredericksburg 12
Planetary 12
Observed AFr/Ap Indices 22 Sep : A K
Fredericksburg 12
Planetary 14 3223 3333
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Sep 10 G0
25 Sep 8 G0
26 Sep 5 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region. G0-G1 conditions were observed in the Antarctic region
with an isolated period of G2 observed at Macquarie Island for
23-Sep. G0 conditions are forecast over 24-26 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Sep Normal Normal Normal-fair
25 Sep Normal Normal Normal-fair
26 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 23-Sep were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 24-26 Sep. Isolated minor shortwave fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Sep 124
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 25% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Enhanced by 20% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Enhanced by 25% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed 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
24 Sep 120 Near to 15% above predicted monthly values
25 Sep 115 Near to 15% above predicted monthly values
26 Sep 110 Near to 15% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 23-Sep were near predicted values to 25% enhanced.
Spread F was observed at Hobart over local night. MUFs are expected
to be near predicted values to enhanced by 15% over 24-26 Sep.
Isolated minor shortwave fadeouts are possible. Equatorial scintillation
possible over 24-26 Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Sep
Daily Proton Fluence >1 MeV: 5.2E+06
Daily Proton Fluence >10 MeV: 1.6E+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: C1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Sep
Speed: 405 km/sec Density: 5.8 p/cc Temp: 165000 K Bz: 4 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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