[Ips-dsgr] ASWFC Daily Report - 15 September 25 issued 2330 UT on 15 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Sep 16 09:30:45 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/15 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 15 SEPTEMBER AND FORECAST FOR 16 SEPTEMBER - 18 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 15 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Sep: 130/84
1B. SOLAR FORECAST
16 Sep 17 Sep 18 Sep
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts Possible Possible Possible
10.7cm/SSN 130/84 130/84 135/89
COMMENT: Solar activity on UT day 15-Sep was at R0. There are
currently six numbered regions visible on the solar disk. AR4216
(N11E32, beta) is the largest of the on disk regions and is mostly
stable with some decay in the trailer spots. AR4217 (S15E63,
beta) was responsible for a number of C class flares over the
UT day and has shown slight growth in its trailer spots. AR4221
(N03E57, beta) has shown growth whilst remaining flare quiet.
All other sunspot regions are either stable or in decay. Solar
activity is expected to be at the R0, chance of R1 over 16-18
Sep. No Earth directed CMEs have been observed S0 solar radiation
storm conditions were observed on UT day 15-Sep. S0 solar radiation
storm conditions are expected over 16-18 Sep. The earth is currently
in the solar wind stream from a large northern hemisphere coronal
hole which will slowly move out of a geoeffective position over
the next UT day. The solar wind speed on UT day 15-Sep quickly
increased through the start of the day then remained elevated
throughout the day ranging from 430 to 780 km/s and is currently
near 760 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 18 nT and the north-south IMF component (Bz) range
was -16 to +12 nT. An interval of southward Bz conditions was
observed as the earth entered the wind stream from 14/2200-15/0200UT.
The solar wind speed is expected remain very strong today and
may start to decline over 17-18 Sep due to the coronal hole moving
out of a geoeffective position.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 15 Sep: G1
Estimated Indices 15 Sep : A K
Australian Region 25 54444333
Cocos Island 16 43333333
Darwin 29 55444334
Townsville 25 54444333
Learmonth 29 54435443
Alice Springs 30 55445333
Gingin 28 54344444
Canberra 22 44444333
Kennaook Cape Grim 30 54455333
Hobart 30 54455333
Estimated Antarctic Regional K Indices 15 Sep :
Macquarie Island 57 55666554
Casey 30 46444343
Mawson 50 75544355
Observed Regional daily pc3 Indices 15 Sep :
Darwin 27 (Quiet to unsettled)
Townsville 17 (Quiet)
Learmonth 26 (Quiet to unsettled)
Alice Springs 19 (Quiet)
Gingin 113 (Major storm)
Canberra 105 (Major storm)
Hobart 142 (Severe 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 15 Sep : A
Fredericksburg 32
Planetary 51
Observed AFr/Ap Indices 14 Sep : A K
Fredericksburg 12
Planetary 14 2232 2235
2B. MAGNETIC FORECAST
Date Ap Conditions
16 Sep 23 G0-G1
17 Sep 17 G0, chance of G1
18 Sep 12 G0
COMMENT: ASWFC Geomagnetic Warning 69 was issued on 15 September
and is current for 15-16 Sep. G1 geomagnetic conditions were
observed in the Australian and G2 with isolated G3 conditions
in Antarctic regions on UT day 15-Sep. Planetary conditions briefly
reached G3 early in the UT day in association with southward
IMF conditions as the Earth entered a coronal hole high speed
wind stream. The wind stream from this coronal hole may cause
periods of G1 geomagnetic conditions on 16-Sep. G0, chance of
G1 is expected over 17-Sep. G0 conditions are expected on 18-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
15 Sep Normal Fair Poor-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
16 Sep Normal Fair Fair
17 Sep Normal Fair-normal Fair
18 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 15-Sep were
degraded at middle to high latitudes. HF radio propagation conditions
are expected to be fair to normal over 16-17 Sep due to declining
geomagnetic activity induced by coronal hole wind stream. HF
condition during local night hours on 16-Sep may remain degraded
at middle to high latitudes. Increased absorption of up to 2db
was observed at times between 15/1100-1900UT at Macquarie Island.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
15 Sep 103
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 25% 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
16 Sep 100 Near predicted monthly values
17 Sep 100 Near predicted monthly values
18 Sep 100 Near predicted monthly values
COMMENT: ASWFC HF Communications Warning 84 was issued on 15
September and is current for 15-17 Sep. Maximum usable frequencies
(MUFs) on UT day 15-Sep were mostly near predicted values. Spread-F
was observed at Hobart during local night hours. The Australian
middle latitude ionosphere has not shown a strong depression
response to recent geomagnetic activity. MUFs are expected to
be near predicted values on 16-18 Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 14 Sep
Daily Proton Fluence >1 MeV: 4.7E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 3.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B8.9
DSCOVR Satellite Solar Wind Day Averaged Data for 14 Sep
Speed: 353 km/sec Density: 6.8 p/cc Temp: 73400 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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