[Ips-dsgr] ASWFC Daily Report - 15 December 25 issued 2330 UT on 15 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Dec 16 10:30:57 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/15 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 15 DECEMBER AND FORECAST FOR 16 DECEMBER - 18 DECEMBER
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 15 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Dec: 118/70
1B. SOLAR FORECAST
16 Dec 17 Dec 18 Dec
Activity R0 R0 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 120/72 120/72 118/70
COMMENT: Solar activity on UT day 15-Dec was R0, with no solar
flares. There are currently four numbered sunspot regions on
the solar disk. Active region (AR) 4307 (S15W45, beta) did show
rapid growth, but showed strong separation suggesting it is nearing
the end of its lifespan. Other sunspots remain relatively stable.
Solar activity is expected to be R0 over 16-18 Dec.
A CME directed to the solar southwest was observed from 15/0012UT but is not
expected to be Earth-directed. No other CMEs were observed on
UT day 15-Dec.
S0 solar radiation storm conditions were observed on UT day 15-Dec.
S0 solar radiation storm conditions are expected over 16-18 Dec.
The solar wind environment on UT day 15-Dec was mostly steady.
The solar wind speed ranged between 450-500km/s. The peak total
interplanetary field strength (IMF, Bt) was 10nT and the north-south
IMF component range (Bz) was +6 to -6nT. The solar wind is expected to
remain near background levels over 16-17 Dec, after which a coronal hole
is expected to enhance the solar wind speed by 18-Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 15 Dec: G0
Estimated Indices 15 Dec : A K
Australian Region 5 11223111
Cocos Island 3 11212100
Darwin 6 21223112
Townsville 8 21224211
Learmonth 6 11223202
Alice Springs 4 11123101
Gingin 6 01224111
Canberra 6 11224101
Kennaook Cape Grim 7 12224111
Hobart 7 12214211
Estimated Antarctic Regional K Indices 15 Dec :
Macquarie Island 5 11114200
Casey 24 35633222
Mawson 11 22333223
Observed Regional daily pc3 Indices 15 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 4 (Quiet)
Hobart 17 (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 15 Dec : A
Fredericksburg 5
Planetary 6
Observed AFr/Ap Indices 14 Dec : A K
Fredericksburg 5
Planetary 7 3212 1121
2B. MAGNETIC FORECAST
Date Ap Conditions
16 Dec 6 G0
17 Dec 14 G0, chance G1
18 Dec 20 G0-G1
COMMENT: ASWFC Geomagnetic Warning 100 was issued on 15 December
and is current for 17-18 Dec. G0 geomagnetic conditions were
observed in the Australian region on UT day 15-Dec. G0-G2 geomagnetic
conditions were observed in the Antarctic region. G0 geomagnetic
conditions are expected over 16 Dec and most of 17 Dec. G1 geomagnetic
conditions are expected by late 17-Dec or else early 18-Dec due
to connection with a coronal hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
15 Dec Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
16 Dec Normal Normal Normal
17 Dec Normal Normal Normal-fair
18 Dec Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 15-Dec were
generally normal, with some persistent depressions and degradations
in the northern hemisphere. HF radio propagation is expected
to be normal over 16-17 Dec, and slightly degraded on 18-Dec.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
15 Dec 110
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Southern Australian Region:
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
16 Dec 105 Near predicted monthly values to 15% enhanced
17 Dec 105 Near predicted monthly values to 15% enhanced
18 Dec 95 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 15-Dec were near predicted values to 20% enhanced.
Sporadic-E was observed in Townsville and Brisbane. MUFs are
expected to be near predicted values to 15% enhanced over 16-18
Dec, possibly trending mildly depressed by the end of the period.
Sporadic-E is expected during local night hours.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 14 Dec
Daily Proton Fluence >1 MeV: 6.5E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.70E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.5
DSCOVR Satellite Solar Wind Day Averaged Data for 14 Dec
Speed: 566 km/sec Density: 1.3 p/cc Temp: 159000 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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