[Ips-dsgr] ASWFC Daily Report - 29 December 25 issued 2330 UT on 29 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Dec 30 10:30:50 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/29 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 29 DECEMBER AND FORECAST FOR 30 DECEMBER - 01 JANUARY
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 29 Dec: R1
Flares Max Fadeout Freq. Sectors
M4.2 28/2239UT possible lower East Pacific/
North American
M2.2 0002UT possible lower West Pacific
M1.0 0651UT possible lower Mid East/Indian
Observed 10.7 cm flux/Equivalent Sunspot Number for 29 Dec: 196/148
1B. SOLAR FORECAST
30 Dec 31 Dec 01 Jan
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 175/129 170/124 165/119
COMMENT: Solar activity on UT day 29-Dec was R1 due to M-class
flares from active region (AR) AR4234 (N26E49, beta-gamma-delta)
and 4235 (S09E33, beta). There are currently six numbered sunspot
regions on the solar disk. AR4324 has shown some minor growth
with some small spots appearing and then decaying, although this
region maintains a small delta spot. AR4325 has grown bigger,
but its leading and trailing spots have diverged to suggest a
peak in its lifecycle. Solar activity is expected to be R1-R2
over 30-31 Dec and 1-Jan.
A CME was observed from 29/1912 UT. Further imagery is required for analysis,
but it is unlikely to be geoeffective. A CME that was observed at the end
of 28-Dec has been analysed with an Earth-directed component arriving
31/1400UT +/- 10 hours.
S0 solar radiation storm conditions were observed on UT day 29-Dec.
S0 solar radiation storm conditions are expected over 30-31 Dec and 1-Jan.
The solar wind environment on UT day 29-Dec was steady.
The solar wind speed ranged from 450 to 400 km/s. The peak total
interplanetary field strength (IMF, Bt) was 8 nT and the north-south
IMF component range (Bz) was +4 to -6 nT. The solar wind is expected
to become disturbed on either late 30-Dec or else early 31-Dec
due to a recurrent coronal hole; a further disturbance is then
expected due to an anticipated CME arrival. Conditions may remain
disturbed over 1-Jan.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 29 Dec: G0
Estimated Indices 29 Dec : A K
Australian Region 7 22232112
Cocos Island 3 11122101
Darwin 7 22232103
Townsville 7 22232122
Learmonth 7 21232103
Alice Springs 5 22222102
Gingin 6 21222103
Canberra 6 22232012
Kennaook Cape Grim 7 22232112
Hobart 6 22222112
Estimated Antarctic Regional K Indices 29 Dec :
Macquarie Island 7 12342001
Casey 18 45433112
Mawson 17 44433223
Observed Regional daily pc3 Indices 29 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 11 (Quiet)
Hobart 26 (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 29 Dec : A
Fredericksburg 9
Planetary 9
Observed AFr/Ap Indices 28 Dec : A K
Fredericksburg 7
Planetary 9 3112 2322
2B. MAGNETIC FORECAST
Date Ap Conditions
30 Dec 15 G0-G1
31 Dec 28 G1-G2, chance G3
01 Jan 16 G0-G1
COMMENT: ASWFC Geomagnetic Warning 103 was issued on 29 December
and is current for 30 Dec to 1 Jan. G0 geomagnetic conditions
were observed on UT day 29-Dec in the Australian region. G0-G1
geomagnetic conditions were observed in the Antarctic region.
G0 geomagnetic conditions are expected until the arrival of a
recurrent coronal hole either late 30-Dec or else early 31-Dec
when G1-G2 conditions are possible. An anticipated CME arrival
is expected mid-31-Dec which is likely to prolong or possible
exacerbate conditions. Conditions are expected to begin declining
on 1-Jan to G0-G1.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
29 Dec Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
30 Dec Normal Normal-fair Fair
31 Dec Normal-fair Fair Fair
01 Jan Normal-fair Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 29-Dec were
normal. HF radio propagation conditions are expected to remain
normal for most of 30-Dec, however degradations may set in either
late in the day or else on 31-Dec. Further degradations are expected
by mid 31-Dec due to an anticipated CME arrival. Conditions likely
to be degraded on 1-Jan but on an improving trend.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
29 Dec 120
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Mostly near predicted monthly values.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Enhanced by 20% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values 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
30 Dec 110 Near predicted monthly values
31 Dec 90 Near predicted values
01 Jan 90 Near predicted monthly values to 15% depressed
COMMENT: ASWFC Preliminary HF Communications Warning 125 was
issued on 29 December and is current for 31 Dec to 1 Jan. Maximum
usable frequencies (MUFs) in the Australian region on UT day
29-Dec were near predicted values to 20% enhanced. Sporadic-E
was prominent along the east coast, particularly in Norfolk Island
and in Brisbane. MUFs are expected to remain enhanced until 31-Dec,
when they are likely to trend to baseline predicted values. Depressions
up to 15% are possible on 1-Jan.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 28 Dec
Daily Proton Fluence >1 MeV: 2.3E+06
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 2.90E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:18%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 28 Dec
Speed: 461 km/sec Density: 3.1 p/cc Temp: 86900 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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