[Ips-dsgr] ASWFC Daily Report - 05 December 25 issued 2330 UT on 05 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Dec 6 10:30:49 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/05 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 05 DECEMBER AND FORECAST FOR 06 DECEMBER - 08 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 05 Dec: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 05 Dec: 206/157
1B. SOLAR FORECAST
06 Dec 07 Dec 08 Dec
Activity R1,chance R2 R1,chance R2 R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 205/156 205/156 200/152
COMMENT: On UT day 5-Dec solar activity was R0. In the southern
solar hemisphere large region AR4294 (S15W04, beta-gamma-delta)
continues to slowly decay. Nearby AR4296 (S14E11, beta-delta)
perhaps shows some growth though appears to be more in overall
decay with umbral fragmentation and nearby AR4298 (S17W19, beta)
has been mostly stable. In the northeast solar quadrant AR4299
(N23E18, beta-delta) shows some recent redevelopment in umbral
area in its trailer spots but appears to be in slow overall decay.
The magnetic delta spots in AR4294, AR4296 and AR4299 are quite
weak. Solar regions AR294, AR4298 and AR4299 produced isolated
C class flare activity, with the largest flare an C7.3 from AR4299
at 05/0209UT. AR4299 appeared to be slightly active with minor
plasma sprays observed at 05/0200UT. Solar region AR4301 (S07W67,
beta) which recently showed rapid growth is now in decay as it
approaches the western solar limb. A small 10 degree long solar
filament located at N40E10 was highly active at 05/0900-1000UT.
There are currently eight solar regions on the visible solar
disk. All other regions are stable or in decay. Western limb
plasma ejecta was observed at solar latitude S20 at 05/0100-0200UT
in GOES SUVI imagery. Solar activity is expected to be R1, chance
R2 over 6-8 Dec. S0 solar radiation storm conditions were observed
on UT day 5-Dec. S0 solar radiation storm conditions are expected
over 6-8 Dec. No Earth directed CMEs have been observed. A narrow
west directed CME was observed in LASCO C2 from 05/0126UT associated
with western limb plasma ejecta and is not considered to be Earth
directed. No CME was associated with the active solar filament.
On UT day 5-Dec the solar wind speed was strong due to ongoing
coronal hole wind stream effects from an equatorial coronal hole
now well west of the solar central meridian. The solar wind speed
ranged from 748 to 600 km/s as is currently at 647 km/s. The
peak total interplanetary field strength (IMF, Bt) was 8 nT.
The north-south IMF component range (Bz) was +6 to -5 nT with.
Whilst the solar wind speed is elevated the embedded magnetic
field is small in magnitude. The solar wind speed is expected
to be strong, slowly declining to moderate over the next two
days. No new coronal holes are currently approaching the solar
central meridian.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 05 Dec: G0
Estimated Indices 05 Dec : A K
Australian Region 11 33322232
Cocos Island 6 22222221
Darwin 12 33322233
Townsville 10 32322232
Learmonth 13 33323332
Alice Springs 11 33322232
Gingin 11 33322232
Canberra 9 23322222
Kennaook Cape Grim 11 33322232
Hobart 11 33322232
Estimated Antarctic Regional K Indices 05 Dec :
Macquarie Island 12 33432222
Casey 33 46643233
Mawson 40 34544374
Observed Regional daily pc3 Indices 05 Dec :
Darwin 15 (Quiet)
Townsville 0 (Quiet)
Learmonth 28 (Quiet to unsettled)
Alice Springs 13 (Quiet)
Gingin 94 (Minor storm)
Canberra 104 (Major storm)
Hobart 109 (Major 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 05 Dec : A
Fredericksburg 13
Planetary 16
Observed AFr/Ap Indices 04 Dec : A K
Fredericksburg 24
Planetary 32 5554 4443
2B. MAGNETIC FORECAST
Date Ap Conditions
06 Dec 12 G0
07 Dec 10 G0
08 Dec 8 G0
COMMENT: Geomagnetic conditions in the Australian region on UT
day 5-Dec were G0. Geomagnetic activity was mildly elevated due
to the declining influence of a coronal hole high speed wind
stream. In the Antarctic region G0-G3 geomagnetic conditions
were observed. G0 geomagnetic conditions are expected over 6-8
Dec. There is a slight chance of a mild increase in geomagnetic
activity on 07-Dec from a possible very weak glancing blow from
a CME observed on 04-Dec.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
05 Dec Normal Normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
06 Dec Normal Normal Normal-fair
07 Dec Normal Normal Normal-fair
08 Dec Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 5-Dec were
fair to normal, with some mild degradations in the polar regions.
In the Antarctic region increased absorption of 2db was observed
on the Mawson riometer during the period 05/0540-0840UT. HF radio
propagation conditions are expected to be normal over 6-8 Dec.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
05 Dec 116
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Near predicted monthly values.
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
06 Dec 105 Near predicted monthly values
07 Dec 105 Near predicted monthly values
08 Dec 105 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 116 was issued on
5 December and is current for 5-6 Dec. Maximum usable frequencies
(MUFs) in the Australian region on UT day 5-Dec were near predicted
monthly values. Mild depressions of 15% were observed after local
dawn at Hobart and Canberra which are not expected to persist.
MUFs are expected to be near predicted monthly values over 6-8
Dec.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 04 Dec
Daily Proton Fluence >1 MeV: 3.2E+06
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 1.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.8
DSCOVR Satellite Solar Wind Day Averaged Data for 04 Dec
Speed: 667 km/sec Density: 2.4 p/cc Temp: 349000 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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