[Ips-dsgr] ASWFC Daily Report - 22 December 25 issued 2330 UT on 22 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Dec 23 10:30:49 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/22 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 22 DECEMBER AND FORECAST FOR 23 DECEMBER - 25 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 22 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 22 Dec: 133/87
1B. SOLAR FORECAST
23 Dec 24 Dec 25 Dec
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 135/89 140/94 145/99
COMMENT: Solar activity was at the R0 level on UT day 22-Dec.
Solar region AR4317 (N13E55, beta-gamma) is a medium sized region
and is currently the largest region on the visible solar disk
and has shown minor growth. Region AR4317 produced the largest
flare for the day, a C8.6 flare at 22/2231UT. Other regions are
quite small, with solar region AR4316 (S07E15, beta-gamma) the
more magnetically complex of the smaller regions that is now
in rapid decay and produced isolated low level C class flares
earlier in the UT day. Small region AR4318 (N05E66, beta) to
the southeast of AR4317 has grown slightly. All other regions
appear stable. There are currently five numbered solar regions
on the visible solar disk. A 15 degree long solar filament located
at S10E35 visible in GONG H-alpha imagery erupted at 22/0854UT.
Solar activity is expected to be at R0-R1 over the period 23-25
Dec. S0 solar radiation storm conditions were observed on 22-Dec.
S0 conditions are forecast for 23-25 Dec. No Earth directed CMEs
have been observed. Two east directed CMEs were observed on 22-Dec.
The first from 22/0512UT and the second from 22/1036UT. The first
CME appears to possibly originate from plasma motion activity
just to the northwest of AR4317 at N10E52 from 22/0354UT. This
east directed CME was analysed and found to have a very slow
speed of only 188 km/s and is considered insignificant. The second
CME has been paired with the southeast filament eruption. Event
modelling shows an Earth miss for this second east directed CME.
The solar wind speed on 22-Dec was very strong due to a coronal
hole wind stream from a coronal hole now west of the solar central
meridian. The solar wind speed ranged from 674 km/s to 790 km/s
and is currently at 711 km/s. The peak total interplanetary field
strength (IMF, Bt) was 9 nT. The north-south IMF component range
(Bz) was +6 nT to -7 nT. The solar wind speed is forecast to
remain strong to very strong for 23-24 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 22 Dec: G0
Estimated Indices 22 Dec : A K
Australian Region 14 32334323
Cocos Island 9 22223322
Darwin 13 32323333
Townsville 15 32334333
Learmonth 17 32334433
Alice Springs 12 32323323
Gingin 17 32334433
Canberra 13 32324323
Kennaook Cape Grim 15 33334323
Hobart 15 33334323
Estimated Antarctic Regional K Indices 22 Dec :
Macquarie Island 26 33346433
Casey 38 66544333
Mawson 50 45545665
Observed Regional daily pc3 Indices 22 Dec :
Darwin 19 (Quiet)
Townsville 0 (Quiet)
Learmonth 8 (Quiet)
Alice Springs 6 (Quiet)
Gingin 56 (Unsettled)
Canberra 87 (Minor storm)
Hobart 132 (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 22 Dec : A
Fredericksburg 18
Planetary 26
Observed AFr/Ap Indices 21 Dec : A K
Fredericksburg 20
Planetary 27 4334 4545
2B. MAGNETIC FORECAST
Date Ap Conditions
23 Dec 24 G0-G1
24 Dec 19 G0-G1
25 Dec 14 G0, chance G1
COMMENT: ASWFC Geomagnetic Warning 101 was issued on 21 December
and is current for 21-23 Dec. G0 geomagnetic conditions were
observed in the Australian region for UT day 22-Dec. Periods
of G1-G2 geomagnetic activity were observed in the Antarctic
region. Planetary G1 conditions were observed. Current geomagnetic
activity is due to a coronal hole wind stream. G0-G1 geomagnetic
conditions are expected on 23-24 Dec, due to ongoing high speed
wind stream effects. These conditions will ease to G0, chance
G1 on 25-Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
22 Dec Normal Fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
23 Dec Normal Fair Fair
24 Dec Normal Fair Fair
25 Dec Normal Fair-normal Fair-normal
COMMENT: HF radio propagation conditions on UT day 22-Dec were
fair to normal. HF conditions are expected to be fair for middle
to high latitudes over 23-24 Dec due to ongoing mild geomagnetic
activity. Isolated minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
22 Dec 75
Observed Australian Regional MUFs
Cocos Island Region:
Depressed by 20% during local day.
Near predicted monthly values during local night.
Niue Island Region:
Mostly near predicted monthly values.
Depressed by 20% after local dawn.
Northern Australian Region:
Mostly near predicted monthly values.
Briefly depressed by 25% after local dawn.
Southern Australian Region:
Near predicted monthly values.
Depressed by 15% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Nov 103
Dec 89
Jan 89
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
23 Dec 75 Depressed 10 to 15%/near predicted monthly values
24 Dec 75 Depressed 10 to 15%/near predicted monthly values
25 Dec 75 Depressed 10 to 15%/near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 22-Dec were near predicted monthly values during
the local day and briefly 15-25% depressed after local dawn this
morning. Spread F was observed during local night hours at Hobart
and Canberra. MUFs are forecast to be 10-15% depressed on 23-25
Dec due to ongoing mild geomagnetic activity. Isolated minor
shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 21 Dec
Daily Proton Fluence >1 MeV: 1.3E+06
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 3.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.7
DSCOVR Satellite Solar Wind Day Averaged Data for 21 Dec
Speed: 614 km/sec Density: 4.0 p/cc Temp: 327000 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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