[Ips-dsgr] ASWFC Daily Report - 31 December 25 issued 2330 UT on 31 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Jan 1 10:30:52 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/31 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 31 DECEMBER AND FORECAST FOR 01 JANUARY - 03 JANUARY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 31 Dec: R2
Flares Max Fadeout Freq. Sectors
M7.1 1351UT probable lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 31 Dec: 171/125
1B. SOLAR FORECAST
01 Jan 02 Jan 03 Jan
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 170/124 165/119 160/114
COMMENT: Solar activity on UT day 31-Dec was at the R2 level
due to an M7.1 flare from solar region AR4324 (N26E15, beta-gamma).
The flare was associated with type II and IV radio sweeps indicating
a CME, however the discrete frequency solar radio burst signature
associated with the flare was relatively weak. This region shows
both growth and decay in its trailer spots. Solar region AR4325
(S09E08, beta-gamma-delta) shows slight development and is the
largest of the on disk regions. Solar region AR4317 (N12W71,
beta) has been stable as it approaches the northwest solar limb.
There are currently seven numbered sunspot regions visible on
the solar disk. All other sunspot regions are either stable or
in decay. Solar activity is expected to be at R1-R2 levels over
01-03 Jan. S0 solar proton conditions were observed on UT day
31-Dec. S0 solar proton conditions are expected over 01-03 Jan.
A partially Earth-directed CME has been observed in association
withe M7.1 flare. The CME is a semi-halo, predominately north-east
directed, however event modelling shows a component Earth
arrival on 02/1900 +/- 12 hours. The solar wind speed on UT day
31-Dec slightly increased then declined, ranging from 400 to
536 km/s and is currently near 435 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 12 nT and the north-south
IMF component (Bz) range was -4 to +11 nT. During the second
half of the UT day solar wind parameters became mildly to moderately
enhanced then declined. The anticipated northwest CME arrival
on 31-Dec from the M4 flare on 28-Dec has failed to eventuate.
There is a slight chance for a weak glancing blow arrival on
01-Jan. The solar wind is expected to be moderately elevated
on 01-Jan. The solar wind is expected to become strongly enhanced
during the second half of 02-Jan and first half of 03-Jan due
to the glancing blow arrival of the M7/CME.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 31 Dec: G0
Estimated Indices 31 Dec : A K
Australian Region 9 22324211
Cocos Island 7 22224100
Darwin 11 23324212
Townsville 13 32325212
Learmonth 12 22325211
Alice Springs 10 22225201
Gingin 9 22324111
Canberra 7 12224201
Kennaook Cape Grim 9 22324201
Hobart 10 22334211
Estimated Antarctic Regional K Indices 31 Dec :
Macquarie Island 11 11235211
Casey 28 56533222
Mawson 15 33334323
Observed Regional daily pc3 Indices 31 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 4 (Quiet)
Canberra 18 (Quiet)
Hobart 20 (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 31 Dec : A
Fredericksburg 7
Planetary 7
Observed AFr/Ap Indices 30 Dec : A K
Fredericksburg 5
Planetary 8 2222 3321
2B. MAGNETIC FORECAST
Date Ap Conditions
01 Jan 16 G0,slight chance G1
02 Jan 45 Initially G0, then G2 second half of UT day.
03 Jan 30 Initially G2, then G0-G1 second half of UT day.
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 31-Dec. The
anticipated CME arrival on 31-Dec has failed to eventuate. G0-G2
geomagnetic conditions were observed in the Antarctic region.
There is a slight chance for G1 conditions on 01-Jan due to a
later than expected arrival of the M4/CME on 28-Dec but it is
now looking unlikely. G2 geomagnetic conditions are now expected
from the second half of the UT day on 02-Jan and into the first
half of the UT day 03-Jan due to the anticipated glancing blow
arrival of the M7/CME observed on 31-Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
31 Dec Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
01 Jan Normal Normal Fair-normal
02 Jan Normal Normal-poor Fair-poor
03 Jan Normal Poor-normal Poor-fair
COMMENT: HF radio propagation conditions on UT day 31-Dec were
normal. HF radio propagation conditions are expected to be mostly
normal on 01-Jan. HF conditions are expected to become fair to
poor on 02-Jan due the anticipated arrival of a CME. Isolated
shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
31 Dec 138
Observed Australian Regional MUFs
Cocos Island Region:
No data.
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 35% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Enhanced by 30% after local dawn.
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
01 Jan 120 Near predicted monthly values to 15% enhanced
02 Jan 110 10-15% enhanced then depressed 20 to 30% late
in the UT day
03 Jan 60 Depressed 20 to 30%/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
31-Dec were near predicted monthly values to 30% enhanced. The
forecast geomagnetic activity on 31-Dec has failed to eventuate.
MUFs are now expected to be 10-15% enhanced on 01-Jan. MUFs are
initially expected to be 10-15% enhanced on 02-Jan then becoming
depressed 20-30% late in the UT day due to the anticipated arrival
of a CME associated with the M7 flare. MUFs on 03-Jan are expected
to be 20-30% depressed. Isolated shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 30 Dec
Daily Proton Fluence >1 MeV: 1.9E+06
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.60E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:14%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 30 Dec
Speed: 397 km/sec Density: 3.4 p/cc Temp: 76600 K Bz: 0 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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