[Ips-dsgr] ASWFC Daily Report - 17 September 25 issued 2330 UT on 17 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Sep 18 09:30:51 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 SEPTEMBER AND FORECAST FOR 18 SEPTEMBER - 20 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 17 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Sep: 147/101
1B. SOLAR FORECAST
18 Sep 19 Sep 20 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 148/102 150/105 150/105
COMMENT: Solar activity on UT day 17-Sep was R0, with no solar
flares. There are currently nine numbered sunspot regions on
the solar disk. AR4220 (S18E00, beta) has shown the most growth
over the past day. Regions AR4221 (N04E29, beta), AR4222 (N11E07,
beta) and AR4223 (S15E49, beta) have shown some minor growth
in the past day. Solar activity is expected to be R0-R1 over
18-20 Sep.
No Earth directed CMEs were observed in available
imagery.
S0 solar radiation storm conditions were observed on
UT day 17-Sep. S0 solar radiation storm conditions are expected
over 18-20 Sep.
The solar wind environment on UT day 17-Sep was
steady. The solar wind speed ranged from 74 trending down to
564 km/s. The peak total interplanetary field strength (IMF,
Bt) was 5 nT and the north-south IMF component range (Bz) was
+4 to -4 nT. The solar wind environment is expected to be near
background levels over 18-20 Sep.
-----------------------------------------------------------
2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Sep: G0
Estimated Indices 17 Sep : A K
Australian Region 6 12222122
Cocos Island 4 12222011
Darwin 7 22322122
Townsville 8 12332122
Learmonth 8 23322022
Alice Springs 5 12222112
Gingin 7 22222132
Canberra 7 12232122
Kennaook Cape Grim 8 22232222
Hobart 9 13332122
Estimated Antarctic Regional K Indices 17 Sep :
Macquarie Island 13 12452221
Casey 18 45432222
Mawson 44 35443267
Observed Regional daily pc3 Indices 17 Sep :
Darwin 8 (Quiet)
Townsville 7 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 22 (Quiet to unsettled)
Canberra 68 (Active)
Hobart 76 (Active)
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 17 Sep : A
Fredericksburg 10
Planetary 11
Observed AFr/Ap Indices 16 Sep : A K
Fredericksburg 17
Planetary 21 5444 4223
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Sep 10 G0
19 Sep 8 G0
20 Sep 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 17-Sep. G0-G2 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 18-20 Sep.
-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Sep Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Sep Normal Normal Normal-fair
19 Sep Normal Normal Normal
20 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 17-Sep were
mildly degraded at the beginning and the end of the day. Conditions
were mostly normal in the middle part of the day. HF radio propagation
conditions are expected to be mostly normal over 18-20 Sep. Equatorial
scintillation is possible during local night hours.
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Sep 99
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 30% during local day.
Enhanced by 30% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Mostly near predicted monthly values.
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
18 Sep 100 Near predicted monthly values
19 Sep 100 Near predicted monthly values
20 Sep 100 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 17-Sep were mostly near predicted values to
15% enhanced. Spread-F was observed in Hobart during local night
hours. MUFs are expected to be near predicted values over 18-20
Sep.
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Sep
Daily Proton Fluence >1 MeV: 1.6e+0.7
Daily Proton Fluence >10 MeV: 1.8e+04
Daily Electron Fluence >2 MeV: 1.00e+08
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B8.5
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Sep
Speed: 718 km/sec Density: 1.3 p/cc Temp: 207000 K Bz: 1 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------
Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
More information about the ips-dsgr
mailing list