[Ips-dsgr] ASWFC Daily Report - 17 September 26 issued 2330 UT on 17 Sep 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Sep 18 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 SEPTEMBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 SEPTEMBER AND FORECAST FOR 18 SEPTEMBER - 20 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Sep: 97/44
1B. SOLAR FORECAST
18 Sep 19 Sep 20 Sep
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 95/41 90/34 90/34
COMMENT: Solar flare activity on UT day 17-Sep was R0, with no
solar flares. There are currently two numbered sunspot regions
on the disk, although they are both decaying and rotating away
out of sight. Solar flare activity is expected to be R0 over
18-20 Sep. No CMEs were observed on UT day 17-Sep. 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 mostly near background levels,
with anticipated CME and coronal hole effects failing to eventuate.
The solar wind speed ranged from 570 to 450 km/s. The peak total
interplanetary field strength (IMF, Bt) was 7 nT and the north-south
IMF component range (Bz) was +6 to -4 nT. The solar wind environment
is expected to be mostly near background levels over 18-20 Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Sep: G0
Estimated Indices 17 Sep : A K
Australian Region 8 21224212
Cocos Island 4 1221-210
Darwin 7 22223212
Townsville 9 21234212
Learmonth 7 22223202
Alice Springs 6 21223202
Gingin 9 22224212
Canberra 8 21134211
Kennaook Cape Grim 9 21234212
Hobart 9 21234212
Estimated Antarctic Regional K Indices 17 Sep :
Casey 18 45433212
Mawson 21 34223326
Observed Regional daily pc3 Indices 17 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 18 (Quiet)
Canberra 14 (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 17 Sep : A
Fredericksburg 14
Planetary 16
Observed AFr/Ap Indices 16 Sep : A K
Fredericksburg 7
Planetary 9 4322 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Sep 6 G0
19 Sep 6 G0
20 Sep 4 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 17-Sep. G0-G1 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 18-20 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Sep Normal Normal Normal
19 Sep Normal Normal Normal
20 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions were mostly normal,
although some degradations were observed throughout the northern
hemisphere across the day. HF radio propagation conditions are
expected to be mostly normal over 18-20 Sep.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Sep 54
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 25% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
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 66
Sep 62
Oct 60
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
18 Sep 60 Near predicted monthly values
19 Sep 60 Near predicted monthly values
20 Sep 65 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 17-Sep were mostly near predicted values. MUFs
are expected to be mostly near predicted monthly values over
18-20 Sep with generally normal conditions.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Sep
Daily Proton Fluence >1 MeV: 7.5E+05
Daily Proton Fluence >10 MeV: 2.0E+04
Daily Electron Fluence >2 MeV: 1.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B2.3
Solar Wind Day Averaged Data for 16 Sep
Speed: 533 km/sec Density: 6.1 p/cc Temp: 234000 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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