[Ips-dsgr] ASWFC Daily Report - 12 December 25 issued 2330 UT on 12 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Dec 13 10:30:51 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/12 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 12 DECEMBER AND FORECAST FOR 13 DECEMBER - 15 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 12 Dec: R1
Flares Max Fadeout Freq. Sectors
M2.0 0505UT possible lower E. Asia/Aust.
M1.1 0544UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 12 Dec: 135/89
1B. SOLAR FORECAST
13 Dec 14 Dec 15 Dec
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 130/84 120/72 120/72
COMMENT: Solar activity was at the R1 level for UT day 12-Dec.
Solar region AR4296 (S14W81, beta-gamma) produced a M2.0 flare
at 12/0505UT and region AR4294 (S14W90, beta-gamma-delta) produced
an M1.1 at 12/0544UT. These two regions continue to decay as
they rotate over the southwest solar limb. Current on disk regions
are small with solar regions AR4305 (S24W02, beta) and AR4307
(S13W13, beta-gamma) both growing. There are currently seven
regions on the visible solar disk. Other regions are stable or in
decay. R0-R1 conditions are forecast for 13-15 Dec. S0 solar
radiation storm conditions were observed on 12-Dec. S0 solar
radiation storm conditions are expected over 13-15 Dec. A north
polar extension coronal hole is currently near the centre of
the solar disk with arms of the hole extending west and east
of the solar central meridian. In GOES 304 a prominence eruption
was observed on the southeast solar limb 12/0000-0600UT and a
possible filament eruption was observed toward the south western
limb from 12/1457UT located at S30W70 with narrow southward directed
plasma motion. The filament eruption could not be confirmed in
H-alpha imagery. No geoeffective coronal mass ejections were
observed over the past UT day. A south west directed CME was
observed from 12/0536UT in LASCO C2 and event timing suggests
correlation with the M2 flare from AR4296. Event modelling shows
the CME passing ahead of the Earth. A slow non Earth directed
CME was observed in association with the southeast solar limb
prominence eruption. No CME appeared associated with the possible
filament eruption. The solar wind speed was moderate and steady,
ranging between 406-500km/s and is currently at 454 km/s. The
peak total interplanetary magnetic field strength (IMF, Bt) was
14 nT and the north-south IMF component (Bz) range was -14 to
10nT. The interplanetary magnetic field strength was enhanced
due to ongoing weak CME influences. The IMF Bz was southward
-5 to -11 nT during the 12/0000-1930UT and more strongly southward
by -14 nT during 12/2030-2200UT. Coronal hole high speed wind
stream effects are expected to sustain elevated wind speed conditions
over 13-14 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 12 Dec: G1
Estimated Indices 12 Dec : A K
Australian Region 26 33344355
Cocos Island 13 32223343
Darwin 24 33343355
Townsville 25 32344355
Learmonth 26 43334355
Alice Springs 25 32344355
Gingin 32 42344465
Canberra 26 33354354
Kennaook Cape Grim 34 33355464
Hobart 34 33354465
Estimated Antarctic Regional K Indices 12 Dec :
Macquarie Island 44 44365654
Casey 26 45533334
Mawson 42 35544565
Observed Regional daily pc3 Indices 12 Dec :
Darwin 5 (Quiet)
Townsville 0 (Quiet)
Learmonth 5 (Quiet)
Alice Springs 2 (Quiet)
Gingin 15 (Quiet)
Canberra 14 (Quiet)
Hobart 54 (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 12 Dec : A
Fredericksburg 20
Planetary 23
Observed AFr/Ap Indices 11 Dec : A K
Fredericksburg 17
Planetary 26 6522 2453
2B. MAGNETIC FORECAST
Date Ap Conditions
13 Dec 20 G1,chance G2 early in UT day
14 Dec 20 G0-G1
15 Dec 12 G0
COMMENT: G1 Geomagnetic conditions were observed on 12-Dec in
the Australian region due to ongoing weak CME influences. G0-G2
geomagnetic conditions were observed in the Antarctic region.
Planetary conditions were G1. G1,chance G2 conditions are expected
early in the UT on 13-Dec due to southward IMF conditions. More
generally G0-G1 conditions are expected over 13-14-Dec, due to
the anticipated Earth entry into a coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
12 Dec Normal Fair Poor-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
13 Dec Normal Fair Poor-fair
14 Dec Normal Normal-fair Fair
15 Dec Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 12-Dec were
fair, with poor to fair conditions at high latitudes. HF conditions
are expected to be fair on 13-Dec and fair to normal on 14-15
Dec, with some degradations possible due to coronal hole high
speed wind stream induced geomagnetic activity. Isolated minor
shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
12 Dec 81
Observed Australian Regional MUFs
Cocos Island Region:
Mostly near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Depressed by 35% after local dawn.
Southern Australian Region:
Depressed by 15% during local day.
Near predicted monthly values during local night.
Depressed by 35% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% 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
13 Dec 65 Depressed 15 to 20%/near predicted monthly values
14 Dec 70 Depressed 10 to 15%/near predicted monthly values
15 Dec 85 Near predicted monthly values
COMMENT: ASWFC HF Communications Warning 121 was issued on 12
December and is current for 13 Dec only. Maximum usable frequencies
(MUFs) in the Australian region on UT day 12-Dec were 35% depressed
to 15% enhanced, with depressed conditions observed in the southern
Australian region. Spread F was observed at Hobart during local
night hours. MUFs in the southern Australian region are 15-35%
depressed after local dawn this morning. MUFs are expected to
be range from 20% depressed to near predicted monthly values
over 13-15 Dec, with mildly degraded HF conditions during local
night hours due to anticipated geomagnetic activity induced by
a coronal hole wind stream. A minor HF fadeout impacting lower
HF frequencies was observed 12/0459-0516UT. Isolated minor shortwave
fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 11 Dec
Daily Proton Fluence >1 MeV: 5.7E+05
Daily Proton Fluence >10 MeV: 1.4E+04
Daily Electron Fluence >2 MeV: 1.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 11 Dec
Speed: 418 km/sec Density: 6.5 p/cc Temp: 38600 K Bz: 4 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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