[Ips-dsgr] ASWFC Daily Report - 30 December 25 issued 2331 UT on 30 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Dec 31 10:31:02 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/30 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 30 DECEMBER AND FORECAST FOR 31 DECEMBER - 02 JANUARY
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 30 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 30 Dec: 182/135
1B. SOLAR FORECAST
31 Dec 01 Jan 02 Jan
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 200/152 200/152 195/147
COMMENT: Solar activity on UT day 30-Dec was at the R0 level,
with several C-class flares observed. There are currently seven
numbered sunspot regions visible on the solar disk. AR4325 (S09E20,
beta-gamma) is the most magnetically complex region on the disk
and has shown spot growth, particularly in its trailer spots.
AR4328 (S14E10, alpha) has shown mild spot growth. All other
sunspot regions are either stable or in decay. Solar activity
is expected to be at R0-R1 levels over 31-Dec to 02-Jan. S0 solar
proton conditions were observed on UT day 30-Dec. S0 solar proton
conditions are expected over 31-Dec to 02-Jan. No Earth-directed
CMEs have been observed. The solar wind speed on UT day 30-Dec
was generally steady, ranging from 380 to 420 km/s and is currently
near 380 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 9 nT and the north-south IMF component (Bz) range
was -6 to +6 nT. The solar wind speed is expected to increase
on 31-Dec due to the combined effects of a coronal hole high
speed wind stream from a northern hemisphere coronal hole and
the arrival of a CME first observed on 28-Dec. The solar wind
speed is expected to remain elevated over 01-02 Jan.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 30 Dec: G0
Estimated Indices 30 Dec : A K
Australian Region 6 22222211
Cocos Island 4 22121201
Darwin 5 21122212
Townsville 7 22222321
Learmonth 6 21222311
Alice Springs 7 22222311
Gingin 6 22222211
Canberra 5 11212221
Kennaook Cape Grim 6 22212221
Hobart 6 22212221
Estimated Antarctic Regional K Indices 30 Dec :
Macquarie Island 10 11134420
Casey 21 35543222
Mawson 14 23333432
Observed Regional daily pc3 Indices 30 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 6 (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 Dec : A
Fredericksburg 8
Planetary 9
Observed AFr/Ap Indices 29 Dec : A K
Fredericksburg 9
Planetary 9 3323 2112
2B. MAGNETIC FORECAST
Date Ap Conditions
31 Dec 28 G1-G2
01 Jan 16 G0-G1
02 Jan 10 G0
COMMENT: ASWFC Geomagnetic Warning 104 was issued on 30 December
and is current for 31 Dec to 1 Jan. G0 geomagnetic conditions
were observed in the Australian region on UT day 30-Dec. G1 geomagnetic
conditions were observed in the Antarctic region. G1-G2 geomagnetic
conditions are expected on 31-Dec due to the combined effects
of a coronal hole high speed wind stream from a northern hemisphere
coronal hole and the arrival of a CME first observed on 28-Dec.
G0-G1 geomagnetic conditions are expected on 01-Jan as CME and
coronal hole effects wane. G0 geomagnetic conditions are expected
on 02-Jan.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
30 Dec Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
31 Dec Fair Fair Fair-poor
01 Jan Normal Normal-fair Fair
02 Jan Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 30-Dec were
normal. HF radio propagation conditions are expected to be fair
on 31-Dec. Normal to fair HF conditions are generally expected
over 01-02 Jan. Isolated shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
30 Dec 137
Observed Australian Regional MUFs
Niue Island Region:
Enhanced by 30% during local day.
Enhanced by 35% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% 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
31 Dec 120 Near to 15% above predicted monthly values
01 Jan 90 Near predicted monthly values
02 Jan 90 Near predicted monthly values
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
30-Dec were near predicted monthly values to 30% enhanced. MUFs
are expected to remain enhanced on 31-Dec, then decline to near
predicted monthly values over 01-02 Jan due to forecast geomagnetic
activity. Isolated shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 29 Dec
Daily Proton Fluence >1 MeV: 1.4E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.90E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:15%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.7
DSCOVR Satellite Solar Wind Day Averaged Data for 29 Dec
Speed: 419 km/sec Density: 4.2 p/cc Temp: 58100 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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