[Ips-dsgr] ASWFC Daily Report - 21 October 26 issued 2336 UT on 21 Oct 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Oct 22 10:36:17 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 OCTOBER 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 OCTOBER AND FORECAST FOR 22 OCTOBER - 24 OCTOBER
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Oct: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Oct: 115/66
1B. SOLAR FORECAST
22 Oct 23 Oct 24 Oct
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts None expected None expected None expected
10.7cm/SSN 115/66 112/63 112/63
COMMENT: Solar flare activity was at the R0 level on UT day 21-Oct,
with no significant flares observed. There are currently three
active sunspot regions on the solar disk, with Active Region
(AR) 4560 (N13W28, beta-gamma) being the largest. This region
has exhibited some mild growth and spot separation over the previous
UT day. Previously flare-active region 4551 (S15W85, alpha) continues
to rotate over the western limb, with only trailing spots visible.
The remaining region, 4557 (N06W53, beta), has exhibited decay.
Solar flare activity is forecast to be at the R0 level over 22-24
Oct, with a chance of R1 given the recent growth of AR 4560.
S0 solar radiation storm conditions were observed throughout
21-Oct, with S0 conditions forecast for 22-24 Oct. A solar eruption
was observed in GOES/SUVI 304A from approximately 21/0600UT,
centred on N40E15. A resultant east-directed, low-velocity coronal
mass ejection (CME) was observed in Stereo-A imaging from 21/0853UT.
Modelling suggests a minor glancing impact from this event is
possible at Earth on 25-Oct. The solar wind speed increased through
the first half of the UT day from approximately 400 km/s to reach
510-530 km/s at 21/1435UT. The solar wind speed then declined
slightly after 21/1500UT, and is currently ranging between 450
and 480 km/s. The interplanetary magnetic field strength (IMF,
Bt) was largely stable throughout the UT day, peaking at 10 nT,
with the north-south component (Bz) ranging between -8 and +5
nT. Sporadic periods of sustained southward Bz were observed
between 21/1503-2105UT. The solar wind is forecast to slowly
decline over 22-24 Oct as the effects of a coronal hole high speed
wind stream wane.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Oct: G0
Estimated Indices 21 Oct : A K
Australian Region 10 22222333
Cocos Island 8 22122332
Darwin 11 32222333
Townsville 9 22122333
Learmonth 12 32222343
Alice Springs 11 32222333
Gingin 12 32222343
Canberra 9 22122333
Kennaook Cape Grim 11 23222333
Hobart 11 23222333
Estimated Antarctic Regional K Indices 21 Oct :
Casey 21 45432234
Mawson 44 45423376
Observed Regional daily pc3 Indices 21 Oct :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 8 (Quiet)
Canberra 38 (Quiet to unsettled)
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 21 Oct : A
Fredericksburg 15
Planetary 18
Observed AFr/Ap Indices 20 Oct : A K
Fredericksburg 7
Planetary 8 3.00
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Oct 12 G0
23 Oct 8 G0
24 Oct 15 G0
COMMENT: Geomagnetic conditions in the Australian region were
at the G0 level on UT day 21-Oct, with G0 conditions also reported
at the planetary level. G2-G3 conditions were recorded in the
Antarctic region. G0 geomagnetic conditions are forecast over
22-24 Oct.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Oct Normal Normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Oct Normal Normal Normal-fair
23 Oct Normal Normal Normal
24 Oct Normal Normal Normal
COMMENT: Global high-frequency (HF) radio propagation conditions
were mostly normal on UT day 21-Oct, with fair conditions observed
in high latitude regions throughout the UT day. Global HF propagation
conditions are forecast to be mostly normal over 22-24 Oct, with
some mild degradations possible early on UT day 22-Oct.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Oct 46
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.
Depressed by 15% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Depressed by 20% after local dawn.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Sep 61
Oct 60
Nov 58
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
22 Oct 50 Near predicted monthly values
23 Oct 50 Near predicted monthly values
24 Oct 50 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) on UT day 21-Oct in
the Australian region were mostly near predicted values, with
some depressions in the northern Australian region after local
dawn. Mild depressions were also observed at Canberra and Hobart.
MUFs are forecast to be near predicted monthly values over 22-24
Oct.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Oct
Daily Proton Fluence >1 MeV: 3.5E+05
Daily Proton Fluence >10 MeV: 2.1E+05
Daily Electron Fluence >2 MeV: 2.11E+07
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B5.4
Solar Wind Day Averaged Data for 20 Oct
Speed: 349 km/sec Density: 5.6 p/cc Temp: 70400 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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