[Ips-dsgr] ASWFC Daily Report - 03 December 25 issued 2330 UT on 03 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Dec 4 10:30:49 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/03 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 03 DECEMBER AND FORECAST FOR 04 DECEMBER - 06 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 03 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 03 Dec: 200/152
1B. SOLAR FORECAST
04 Dec 05 Dec 06 Dec
Activity R1,chance R2 R1,chance R2 R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 205/156 210/161 210/161
COMMENT: Solar activity was at the R0 level over the UT day 03-Dec.
Large solar region AR4294 (S15E24, beta-gamma-delta) is currently
in decay with penumbra spreading and breaking up and a decline
in umbral area within the large trailer spot. The intermediate
spots of this region initially showed some development then started
to decay. Nearby region AR4296 (S14E39, beta-delta) exhibited
minor growth in its intermediate spots, though its main leader
spot may be in initial decay. Solar region AR4298 (S17E09, beta),
which is mostly a simple large monopole spot showed some minor
growth in opposite polarity surrounding small spots to the north
of the main spot. These three regions are in a sequence in the
southeast solar quadrant. Solar region AR4299 (N23E45, beta)
located in the northeast solar quadrant is in slight decay, with
a reduction in umbral area of its trailer spots. In the southwest
solar quadrant smaller solar region AR4297 (S11W38, beta) is
rapidly growing. Solar regions AR4297 and AR4299 produced low
to middle level C class flares. Currently, there are ten numbered
sunspot regions on the visible solar disk. All other sunspot
regions on the disk are either stable or in decay. On the northwest
solar limb near AR4288 (N19W86, beta) plasma arch movement and
plasma ejecta was observed from 03/1251UT in GOES imagery. A
section of solar filament near AR4288 also appeared to lift off
during this activity. Solar activity is expected to be at the
R1,chance R2 level over 04-06 Dec. Solar radiation storm conditions
were at the S0 level during UT day 03-Dec, and S0, chance S1
conditions are forecast over the period 04-06 Dec. There were
no significantly Earth directed coronal mass ejections observed
over the past UT day. A narrow eastward non-Earth directed CME
was observed from 03/0105UT. Two faint CMEs directed to the southwest
were observed from 03/0105UT and 03/0828UT. The first CME was
too faint to model. The second event may be associated with filament
activity in the southwest solar quadrant centred at S20W50 visible
in GOES 304 imagery. The second CME was found to have a very
slow speed (<200km/s) and is not considered significant. A west
CME was observed from 03/1106UT which could not be correlated
to disk activity, so at this stage is assumed to be far side,
and may have subsequently overlapped with a northwest CME associated
with the north western limb plasma activity. These CMEs are expected
to pass ahead of the Earth. The solar wind speed on UT day 03-Dec
increased toward the end of the UT day as the Earth's entered
the coronal hole wind stream from the equatorial coronal hole
now located in the western solar hemisphere. The solar wind speed
ranged from 496 to 368 km/s, and is currently at 495 km/s. The
peak total interplanetary field strength (IMF, Bt) was 18 nT
and the north-south IMF component range (Bz) was +13 to -13nT.
The IMF Bz component gradually drifted increasingly southward
from 03/0700UT and the total interplanetary field gradually increased.
Two periods of southward IMF conditions were observed 03/1630-1830UT
and from 03/2000-2130UT. The solar wind speed is expected to
remain elevated over 04-05 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 03 Dec: G1
Estimated Indices 03 Dec : A K
Australian Region 22 11235445
Cocos Island 16 11224444
Darwin 22 21235445
Townsville 20 11235345
Learmonth 26 11245455
Alice Springs 18 11235344
Gingin 26 11245455
Canberra 20 12234445
Kennaook Cape Grim 21 12245444
Hobart 24 12245454
Estimated Antarctic Regional K Indices 03 Dec :
Macquarie Island 41 12265664
Casey 34 56443444
Mawson 29 23334564
Observed Regional daily pc3 Indices 03 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 9 (Quiet)
Canberra 16 (Quiet)
Hobart 47 (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 03 Dec : A
Fredericksburg 9
Planetary 10
Observed AFr/Ap Indices 02 Dec : A K
Fredericksburg 9
Planetary 10 2322 2232
2B. MAGNETIC FORECAST
Date Ap Conditions
04 Dec 40 G1-G2
05 Dec 25 G1
06 Dec 17 G0
COMMENT: ASWFC Geomagnetic Warning 95 was issued on 3 December
and is current for 4-5 Dec. G1 geomagnetic conditions were observed
in the Australian region on 03-Dec. G2 conditions were observed
in the Antarctic region. Planetary conditions reached G3 in association
with southward IMF conditions late in the UT day on 03-Dec. G1
geomagnetic conditions are expected on the over 04-05 Dec due
to a high speed solar wind stream from an equatorial coronal
hole, with isolated G2 periods on 04-Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
03 Dec Normal Normal-fair Normal-poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
04 Dec Normal Fair Fair-poor
05 Dec Normal Fair-normal Fair-poor
06 Dec Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 03-Dec were
initially normal, then becoming degraded toward then end of the
UT day. HF conditions are expected to fair to poor on the 04-Dec
at middle to high latitudes due to geomagnetic activity associated
with a coronal hole high speed wind stream. Absorption of 2dB
was observed on the Mawson riometer during the period 03/06-09UT
and the Macquarie Island riometer observed 1-2 db absorption
at times late in the UT day. Generally fair conditions are expected
on the 05-Dec, with periods of poor conditions at higher latitudes.
Shortwave fadeouts are possible on daylight HF circuits.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
03 Dec 122
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Enhanced by 30% after local dawn.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 25% during local night.
Depressed by 20% after local dawn.
Southern Australian Region:
Mostly near predicted monthly values.
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
04 Dec 70 Depressed 15 to 20%/near predicted monthly values
05 Dec 80 Depressed 10 to 15%/near predicted monthly values
06 Dec 90 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 114 was issued on
2 December and is current for 2-4 Dec. ASWFC HF Communications
Warning 115 was issued on 3 December and is current for 4 Dec
only. Maximum usable frequencies (MUFs) in the Australian region
on UT day 03-Dec were near predicted monthly values to 15% enhanced
during the local day yesterday, then becoming depressed by 20%
after local dawn this morning following overnight geomagnetic
activity. Spread F was observed at Hobart during local night
hours. MUFs are expected to be 15-20% depressed for 04-Dec and
10-15% depressed on 05-Dec. Shortwave fadeouts are possible on
daylight HF circuits.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 02 Dec
Daily Proton Fluence >1 MeV: 1.2E+06
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 3.40E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:20%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 02 Dec
Speed: 405 km/sec Density: 1.7 p/cc Temp: 78800 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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