[Ips-dsgr] ASWFC Daily Report - 22 September 26 issued 2330 UT on 22 Sep 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Sep 23 09:30:53 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/22 SEPTEMBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 22 SEPTEMBER AND FORECAST FOR 23 SEPTEMBER - 25 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 22 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 22 Sep: 118/70
1B. SOLAR FORECAST
23 Sep 24 Sep 25 Sep
Activity R0, chance R1 R0, chance R1 R0, chance R1
Fadeouts None expected None expected None expected
10.7cm/SSN 120/72 120/72 122/75
COMMENT: Solar flare activity was at the R0 level on 22-Sep,
with three C-class flares recorded over the period. Nine active
regions are currently on the solar disk. Active Region (AR) 4534
(N10W32, beta) has remained dynamic in nature, with sunspot growth
followed by later decay in the UT day. The past 24 hours has
seen the development of AR 4539 (S10E30, beta). AR 4536 (N03W10)
has seen some growth over the 22-Sep. AR 4537 (N07W24, beta)
and 4538 (N12W20, beta) have also grown in size and sunspot number.
Two other small ARs have developed close to the western limb.
These are AR 4540 (S11W49, beta) and a yet unnumbered region
(S05W44, beta). All other regions have remained stable. Solar
flare activity is forecast at the R0 level, with a chance of
R1 over 23-25 Sep. Solar radiation storm conditions were at the
S0 level on 22-Sep, with the solar proton flux at background
levels. S0 solar radiation storm conditions are forecast over
23-25 Sep. No Earth-directed coronal mass ejections (CMEs) were
observed over the past UT day. The solar wind environment was
stable ranging from 340-290 km/s, the latter value being the
current speed. The interplanetary magnetic field strength (IMF,
Bt) was stable over the UT day, peaking at 4.8 nT. The north-south
component (Bz) ranged between -4.1 and +3.6 nT over the same
period. The solar wind speed is expected to rise over the 23-Sep,
as the Earth begins to connect with a coronal hole high speed
wind stream. The solar wind speed is expected to remain elevated
over the 24-Sep due to this high speed wind stream, before declining
throughout the 25-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 22 Sep: G0
Estimated Indices 22 Sep : A K
Australian Region 1 11000100
Cocos Island 1 11010100
Darwin 2 12100111
Townsville 1 11000111
Learmonth 1 10000101
Alice Springs 1 11000100
Gingin 1 10000101
Canberra 0 01000000
Kennaook Cape Grim 1 11000100
Hobart 1 11000100
Estimated Antarctic Regional K Indices 22 Sep :
Casey 5 23210111
Mawson 10 42000005
Observed Regional daily pc3 Indices 22 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (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 22 Sep : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 21 Sep : A K
Fredericksburg 2
Planetary 3 2101 1001
2B. MAGNETIC FORECAST
Date Ap Conditions
23 Sep 24 G1
24 Sep 24 G1
25 Sep 8 G0
COMMENT: Geomagnetic conditions in the Australian region were
at the G0 level over the 22-Sep, with G0 geomagnetic conditions
also recorded at the planetary scale. A single period of G1 was
observed in the Antarctic region at Mawson, with geomagnetic
conditions otherwise being at G0. G1 planetary geomagnetic conditions
are forecast on 23-24 Sep due to high speed wind stream effects
and the solar equinox. The solar equinox period can heighten
geomagnetic activity. G0 geomagnetic conditions are expected
on the 25-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
22 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
23 Sep Normal Normal-fair Fair
24 Sep Normal Normal-fair Fair
25 Sep Normal Normal Normal-fair
COMMENT: Global high-frequency (HF) radio propagation conditions
on the 22-Sep were normal. Global HF conditions are expected
to be mildly degraded on 23-24 Sep due to forecast geomagnetic
activity. Conditions are expected to return to normal over the
25-Sep.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
22 Sep 71
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 25% during local day.
Enhanced by 15% during local night.
Enhanced by 30% after local dawn.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
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
23 Sep 50 Near predicted monthly values
24 Sep 45 Near predicted monthly values
25 Sep 60 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region were mostly near predicted monthly values over UT day
22-Sep, with notable enhancements seen at Niue. Mild spread-F
was observed at Canberra. MUFs are forecast to be near predicted
monthly values over 23-25 Sep. While depressions are expected
due to anticipated geomagnetic activity, current MUFs are already
mildly elevated above predicted monthly values.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 21 Sep
Daily Proton Fluence >1 MeV: 3.4E+05
Daily Proton Fluence >10 MeV: 2.0E+04
Daily Electron Fluence >2 MeV: 2.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B2.6
Solar Wind Day Averaged Data for 21 Sep
Speed: 333 km/sec Density: 1.7 p/cc Temp: 49900 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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