[Ips-dsgr] ASWFC Daily Report - 30 September 26 issued 2330 UT on 30 Sep 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Oct 1 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/30 SEPTEMBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 30 SEPTEMBER AND FORECAST FOR 01 OCTOBER - 03 OCTOBER
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 30 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 30 Sep: 93/38
1B. SOLAR FORECAST
01 Oct 02 Oct 03 Oct
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 95/41 95/41 90/34
COMMENT: Solar flare activity was at the R0 level on UT day 30-Sep,
with one high level C class flare observed. There are currently
two active sunspot regions on the visible disk, with Active Region
(AR) 4535 (N11W56, beta) being the largest. This region has shown
growth in the centre spot and some mild decay of the trailer
spots over the past 24 hours. All other sunspot regions are either
stable or in decay. Solar flare activity is forecast to remain
at the R0 level through the period 01-03 Oct. S0 solar radiation
storm conditions were observed throughout 30-Sep, with S0 conditions
forecast over 01-03 Oct. A weak Coronal mass ejection (CME) from
a C8.6 flare was first observed 0238UT on SDO/AIA 304. Modelling
of this event suggests that the bulk of this eruption will pass
ahead and above the Earth. However, part of this event is expected
to impact Earth, with a glancing CME arrival at Earth forecast
on 03-Oct at 1800UT +/-10 hours. The solar wind environment was
at background levels throughout 30-Sep, with the solar wind speed
remaining between 270 and 310km/s, currently at 300km/s. The
interplanetary magnetic field strength (IMF, Bt) was stable throughout
the UT day, peaking at 5 nT, with the north-south component (Bz)
ranging between -2 and +4 nT. The solar wind is expected to remain
at background levels at the start of 01-Oct, with a rise in the
solar wind speed forecast late on 01-Oct due to the glancing
impact of a CME first observed on 28-Sep. The solar wind speed
will continue to rise on 02-Oct due to the ongoing impact of
this CME.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 30 Sep: G0
Estimated Indices 30 Sep : A K
Australian Region 1 11011001
Cocos Island 1 12010000
Darwin 2 21111001
Townsville 2 12011011
Learmonth 2 21001001
Alice Springs 2 12011000
Gingin 2 21001001
Canberra 1 01001001
Kennaook Cape Grim 1 11011000
Hobart 1 02001000
Estimated Antarctic Regional K Indices 30 Sep :
Casey 7 34211011
Mawson 5 41002002
Observed Regional daily pc3 Indices 30 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 30 Sep : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 29 Sep : A K
Fredericksburg 3
Planetary 4 2011 111-
2B. MAGNETIC FORECAST
Date Ap Conditions
01 Oct 10 G0, chance of G1
02 Oct 24 G1, chance of G2
03 Oct 10 G0, chance of G1
COMMENT: Geomagnetic conditions in the Australian region were
at the G0 level on UT day 30-Sep, with G0 conditions also recorded
in both the Antarctic region and at the planetary level. G0,
chance of G1 geomagnetic conditions are forecast for 01-Oct due
to the arrival of a CME late in the UT day that was first observed
on 28-Sep. G1 geomagnetic conditions, with a chance of G2, are
forecast for 02-Oct due to the ongoing effects of this CME arrival
before easing to G0, chance of G1 with possible glancing arrival
of a CME late in the UT day that was first observed 30-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
30 Sep Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
01 Oct Normal Normal Normal-fair
02 Oct Normal Normal-fair Fair
03 Oct Normal Normal Normal-fair
COMMENT: Global high-frequency (HF) radio propagation conditions
on 30-Sep were normal to fair, with some degradations in northern
hemisphere mid and high latitude regions and southern hemisphere
mid-latitude region during local night hours. Global HF propagation
conditions are forecast to remain mostly normal over 01-Oct,
with normal to fair conditions forecast on 02-Oct due to anticipated
geomagnetic activity then returning to mostly normal over 03-Oct.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
30 Sep 62
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 20% 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
01 Oct 60 Near predicted monthly values
02 Oct 50 Decreased by 10-15%/Near predicted monthly values
03 Oct 60 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region were mostly near predicted values on 30-Sep, with some
isolated depressions observed at Townsville during local night
hours. Ionospheric scintillation was also recorded at Learmonth
between 30/1156-1211UT. Spread-F was observed in Hobart during
local night hours. MUFs are forecast to remain near predicted
values over 01-Oct, with depressions of 10-15% forecast on 02-Oct
due to anticipated geomagnetic activity then near predicted values
over 03-Oct.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 29 Sep
Daily Proton Fluence >1 MeV: 6.9E+05
Daily Proton Fluence >10 MeV: 2.3E+04
Daily Electron Fluence >2 MeV: 2.20E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:16%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B3.0
Solar Wind Day Averaged Data for 29 Sep
Speed: 297 km/sec Density: 2.7 p/cc Temp: 41500 K Bz: -1 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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