[Ips-dsgr] ASWFC Daily Report - 23 December 25 issued 2330 UT on 23 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Dec 24 10:30:51 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 DECEMBER AND FORECAST FOR 24 DECEMBER - 26 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Dec: 142/96
1B. SOLAR FORECAST
24 Dec 25 Dec 26 Dec
Activity R0 R0 R1
Fadeouts None expected None expected Possible
10.7cm/SSN 145/99 150/105 155/109
COMMENT: Solar activity was at the R0 level on UT day 23-Dec.
Solar region AR4317 (N11E37, beta) has grown slightly. This medium
sized region is currently the largest of the on disk regions
and produced low level C class flares. Solar region AR4316 (S07W00,
beta) trailer spots have recently mostly decayed and this region
produced an isolated low level C class flare. A number of new
small spots are rapidly emerging at S13E08 just to the southeast
of AR4316. These new spots appear to have a beta magnetic configuration.
Solar region AR4319 (S08E58, beta) has shown slight growth. There
are currently seven numbered solar regions and one unnumbered
region on the visible solar disk. Other regions are stable or
in decay. Plasma ejecta was observed on the western solar limb
at solar latitude S10-S20 from 23/1457UT. Solar activity is expected
to be at R0 for 24-25 Dec, with R1 activity on 26-Dec due to
the possible return of previously flare active AR4294. There
is some behind the limb emission on the southeast solar limb
in SDO171 imagery at S15, but at this stage the visible emission
does not appear to be very large and the background solar X-ray
flux remains relatively flat at present. S0 solar radiation storm
conditions were observed on 23-Dec. S0 conditions are forecast
for 24-26 Dec. No Earth directed CMEs have been observed. A north
northeast CME was in progress at the start of the UT day following
an northeast limb prominence eruption. A west directed CME was
observed from 23/1512UT associated with the west limb plasma
ejecta. These solar limb CME events are not considered Earth
directed. The solar wind speed on 23-Dec was very strong due
to a coronal hole wind stream from a coronal hole now well west
of the solar central meridian. The solar wind speed ranged from
660 km/s to 750 km/s and is currently at 715 km/s. The peak total
interplanetary field strength (IMF, Bt) was 7 nT. The magnitude
of the IMF has been relatively small. The north-south IMF component
range (Bz) was +5 nT to -5 nT. The solar wind speed is forecast
to be strong for 24-25 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 Dec: G0
Estimated Indices 23 Dec : A K
Australian Region 15 23334333
Cocos Island 10 22223332
Darwin 15 23334333
Townsville 15 23334333
Learmonth 15 23334333
Alice Springs 14 23333333
Gingin 14 23334332
Canberra 14 23333333
Kennaook Cape Grim 15 23334333
Hobart 15 23334333
Estimated Antarctic Regional K Indices 23 Dec :
Macquarie Island 28 23456432
Casey 39 56644343
Mawson 34 34544464
Observed Regional daily pc3 Indices 23 Dec :
Darwin 17 (Quiet)
Townsville 13 (Quiet)
Learmonth 8 (Quiet)
Alice Springs 4 (Quiet)
Gingin 79 (Active)
Canberra 87 (Minor storm)
Hobart 91 (Minor 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 23 Dec : A
Fredericksburg 16
Planetary 22
Observed AFr/Ap Indices 22 Dec : A K
Fredericksburg 17
Planetary 25 4343 5444
2B. MAGNETIC FORECAST
Date Ap Conditions
24 Dec 19 G0-G1
25 Dec 14 G0,chance G1
26 Dec 12 G0,chance G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
region for UT day 23-Dec. Periods of G1-G2 geomagnetic activity
were observed in the Antarctic region. The current mild geomagnetic
activity is due to a coronal hole wind stream. G0-G1 geomagnetic
conditions are expected on 24-Dec, due to ongoing high speed
wind stream effects. These conditions will ease to G0, chance
G1 on 25-26 Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 Dec Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 Dec Normal Fair-normal Fair
25 Dec Normal Normal Normal-fair
26 Dec Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 23-Dec were
fair to normal. HF conditions are expected to be fair for middle
to high latitudes on 24-Dec due to ongoing mild geomagnetic activity,
becoming fair to normal over 25-26 Dec. Isolated minor shortwave
fadeouts are possible from 26-Dec.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 Dec 97
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Southern Australian Region:
Depressed 15% to near predicted monthly values.
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
24 Dec 80 Depressed 10 to 15%/near predicted monthly values
25 Dec 90 Near predicted monthly values
26 Dec 90 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 23-Dec were 15% depressed to 15% enhanced. Spread
F was observed during local night hours at Hobart. MUFs are forecast
to be 10-15% depressed to near predicted monthly values on 24-Dec
and near predicted monthly values for 25-26 Dec. Isolated minor
shortwave fadeouts are possible from 26-Dec.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 Dec
Daily Proton Fluence >1 MeV: 5.4E+06
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 4.80E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B9.1
DSCOVR Satellite Solar Wind Day Averaged Data for 22 Dec
Speed: 719 km/sec Density: 2.5 p/cc Temp: 229000 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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