[Ips-dsgr] ASWFC Daily Report - 11 December 25 issued 2330 UT on 11 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Dec 12 10:30:50 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/11 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 11 DECEMBER AND FORECAST FOR 12 DECEMBER - 14 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 11 Dec: R0
Flares Max Fadeout Freq. Sectors
M4.4 10/2208UT possible lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 11 Dec: 146/100
1B. SOLAR FORECAST
12 Dec 13 Dec 14 Dec
Activity R1-R2 R1 R1
Fadeouts Possible Possible Possible
10.7cm/SSN 170/124 165/119 165/119
COMMENT: Solar activity was at the R0 level for UT day 11-Dec,
with no significant flare events observed in the last 24 hours.
There are currently eight regions on the solar surface, with
Active Region (AR) 4294 (S15W83, beta-gamma) being the most magnetically
complex. This region has shown some mild decay as it moves towards
the solar limb. Recently numbered AR 4307 (S13E11, beta), as
well as AR 4305 (S25E20, beta) have both shown some growth over
the last UT day, with all other regions stable or in decay. R1-R2
conditions are forecast for 12 Dec, decreasing to R1 over 13-14
Dec as the most active sunspot regions rotate over the visible
surface of the disk. S0 solar radiation storm conditions were
observed over the past 24 hours, with the proton flux at background
levels. Solar radiation storm conditions are forecast to be at
the S0 level over the period 12-14 Dec. There were no geoeffective
Coronal Mass Ejections (CMEs) observed over the past UT day.
The solar wind speed was elevated for 11-Dec due to the CME arrival
late on 10-Dec, peaking between 450-500 km/s early in the UT
day. The solar wind speed has slowly declined from this peak,
with additional perturbations observed due to ongoing geomagnetic
activity, ranging between 390-420km/s over the last 6 hours.
The interplanetary magnetic field strength (IMF, Bt) peaked at
22 nT during 11-Dec. The North-South component (Bz) ranged between
-16 and +16 nT during the last 24 hours, with three periods of
significant southward Bz between 11/0000-0200UT, 11/1400-1500UT,
and 11/1600-1730UT. The solar wind speed will continue to ease
over 12 Dec, before the onset of high speed wind stream effects
from an equatorial hole cause an increase in the solar wind during
13-14 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 11 Dec: G1
Estimated Indices 11 Dec : A K
Australian Region 20 43222551
Cocos Island 18 42122551
Darwin 21 43223552
Townsville 22 43233552
Learmonth 28 52233562
Alice Springs 21 43223551
Gingin 23 53222552
Canberra 17 43122451
Kennaook Cape Grim 17 43222451
Hobart 17 43222451
Estimated Antarctic Regional K Indices 11 Dec :
Macquarie Island 25 54222461
Casey 30 56433442
Mawson 44 66423555
Observed Regional daily pc3 Indices 11 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 6 (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 11 Dec : A
Fredericksburg 18
Planetary 25
Observed AFr/Ap Indices 10 Dec : A K
Fredericksburg 16
Planetary 21 3232 2236
2B. MAGNETIC FORECAST
Date Ap Conditions
12 Dec 24 G0-G1
13 Dec 21 G0-G1
14 Dec 20 G0-G1
COMMENT: ASWFC Geomagnetic Warning 98 was issued on 10 December
and is current for 10-12 Dec. G1 Geomagnetic conditions were
observed during 11-Dec in the Australian region, with a weak
(24nT) impulse observed at 1500UT due to ongoing effects from
a Coronal Mass Ejection impact. Several periods of G2 geomagnetic
conditions were also observed in the Antarctic region, which
was also seen at the planetary level. Geomagnetic conditions
are forecast at the G0-G1 level over 12-Dec, as the effects of
the previous impact begin to subside. G0-G1 conditions will remain
over 13-14 Dec, as an equatorial coronal hole rotates into a
geoeffective position.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
11 Dec Normal-fair Normal-fair Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
12 Dec Normal-fair Normal-fair Fair-normal
13 Dec Normal-fair Normal-fair Fair-normal
14 Dec Normal-fair Normal-fair Fair-normal
COMMENT: HF radio propagation conditions on UT day 11-Dec were
mostly normal, with fair conditions observed during nighttime
hours in the South American region, and during daytime hours
in the African region. Some enhancements were observed in the
Australian and Asian regions. Conditions are expected to be normal-fair
over 12-Dec due to ongoing geomagnetic activity. Conditions will
remain normal-fair on 13-14 Dec, with some degradations possible
due to coronal hole high speed wind stream effects. Shortwave
fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
11 Dec 117
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Enhanced by 25% after local dawn.
Southern Australian Region:
Enhanced by 20% during local day.
Near predicted monthly values during local night.
Depressed by 20% 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
12 Dec 110 Near predicted monthly values
13 Dec 110 Near predicted monthly values
14 Dec 110 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) were near predicted
monthly values to 20% enhanced during UT day 11-Dec for the Australia
region, with near predicted monthly values seen in the Antarctic
region. Low frequency sporadic-E was observed in the southern
Australian region and Niue Island, with spread F also observed
in Hobart during local night hours. MUFs are forecast to trend
towards near predicted monthly values throughout 12-Dec, due
to the ongoing geomagnetic activity. These conditions will remain
over 13-14 Dec as the Earth makes a connection to a coronal hole
high speed wind stream. Sporadic-E during local night hours may
be observed. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 10 Dec
Daily Proton Fluence >1 MeV: 1.8E+06
Daily Proton Fluence >10 MeV: 1.4E+04
Daily Electron Fluence >2 MeV: 4.00E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.7
DSCOVR Satellite Solar Wind Day Averaged Data for 10 Dec
Speed: 389 km/sec Density: 5.8 p/cc Temp: 48300 K Bz: -3 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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