[Ips-dsgr] ASWFC Daily Report - 26 September 25 issued 2330 UT on 26 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Sep 27 09:30:50 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 SEPTEMBER AND FORECAST FOR 27 SEPTEMBER - 29 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.6 2001UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Sep: 165/119
1B. SOLAR FORECAST
27 Sep 28 Sep 29 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 165/119 165/119 160/114
COMMENT: Solar activity on UT day 26-Sep was R1, with an isolated
M1.6 solar flare from a region rotating over from the northeastern
solar limb, not yet in view. There are currently nine numbered
sunspot regions on the solar disk. AR4224 (S16W78, beta), AR4229
(S04W73, beta) and AR4230 (S09E18, beta) have all grown slightly,
but in general the sunspots remain stable. Solar activity is
expected to be R0-R1 over 27-29 Sep.
No Earth directed CMEs were observed on UT day 26-Sep.
S0 solar radiation storm conditions were observed on UT day 26-Sep.
S0 solar radiation storm conditions are expected over 27-29 Sep.
The solar wind environment on UT day 26-Sep was steady and undisturbed.
The solar wind speed ranged from 489 trending down to 388 km/s.
The peak total interplanetary field strength (IMF, Bt) was 5 nT
and the north-south IMF component range (Bz) was -3 to +4 nT.
The solar wind is expected to be near background levels over 27-29 Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 Sep: G0
Estimated Indices 26 Sep : A K
Australian Region 3 11121012
Cocos Island 2 11110011
Darwin 4 21111022
Townsville 4 21121012
Learmonth 5 22121122
Alice Springs 3 11121012
Gingin 6 22122122
Canberra 3 11022011
Kennaook Cape Grim 3 11122011
Hobart 4 12122011
Estimated Antarctic Regional K Indices 26 Sep :
Macquarie Island 3 12022010
Casey 10 43321112
Mawson 22 34321164
Observed Regional daily pc3 Indices 26 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 28 (Quiet to unsettled)
Canberra 37 (Quiet to unsettled)
Hobart 8 (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 26 Sep : A
Fredericksburg 6
Planetary 7
Observed AFr/Ap Indices 25 Sep : A K
Fredericksburg 7
Planetary 8 1123 3212
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Sep 8 G0
28 Sep 6 G0
29 Sep 8 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 26-Sep. G0-G2 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 27-29 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Sep Normal Normal Normal
28 Sep Normal Normal Normal
29 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 26-Sep were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 27-20 Sep.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Sep 119
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Enhanced by 25% during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 45% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Enhanced by 15% during local day.
Enhanced by 15% during local night.
Enhanced by 30% after local dawn.
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
27 Sep 120 Near to 20% above predicted monthly values
28 Sep 120 Near to 20% above predicted monthly values
29 Sep 120 Near to 20% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 26-Sep were near predicted values to 30% enhanced.
MUFs are expected to be near predicted values to 20% enhanced
over 27-29 Sep. Equatorial scintillation is possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Sep
Daily Proton Fluence >1 MeV: 5.5E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 2.80E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 4%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.4
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Sep
Speed: 483 km/sec Density: 0.1 p/cc Temp: 76200 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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