[Ips-dsgr] ASWFC Daily Report - 04 December 25 issued 2330 UT on 04 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Dec 5 10:30:50 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/04 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 04 DECEMBER AND FORECAST FOR 05 DECEMBER - 07 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 04 Dec: R2
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Dec: 220/170
1B. SOLAR FORECAST
05 Dec 06 Dec 07 Dec
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 220/170 220/170 215/165
COMMENT: On UT day 4-Dec solar activity was R2, with an isolated
M6.1 class solar flare from new active sunspot region (AR) 4300
(N07E39, beta). There are currently seven numbered sunspot regions
on the solar disk. AR 4294, while still the largest region, may
be beginning to mature but has overall not increased in complexity.
Neighboring region AR 4296 (S14E25, beta-delta) is also maturing,
but maintains a prominent delta region. AR 4301 (S07W56, beta)
has shown rapid growth over the past day, but has been quiet.
Solar activity is expected to be R1-R2 over 5-7 Dec.
A CME was associated with the R2 flare event that was deflected to the
east of the Sun. Another CME directed to the southeast was observed
from 0700 UT associated with filament movement near AR4294. These
CMEs are expected to pass behind the Earth.
S0 solar radiation storm conditions were observed on UT day 4-Dec.
S0 solar radiation storm conditions are mostly expected over 5-7 Dec.
On UT day 4-Dec the solar wind environment was disturbed due to ongoing
coronal hole effects. The solar wind speed rose to near 700 km/s
and remained at this level for most of the day. The peak total
interplanetary field strength (IMF, Bt) was 21nT, possibly due
to a co-rotating interaction region or else glancing blow from
the CME associated with the R3 event on 01-Dec. Bt settled to
background levels at the end of the day. The north-south IMF
component range (Bz) was +13 to -14nT with. The solar wind is
expected to settle to background conditions over 5-7 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 04 Dec: G0
Estimated Indices 04 Dec : A K
Australian Region 18 33344333
Cocos Island 13 32324332
Darwin 16 33333334
Townsville 18 43343333
Learmonth 18 33344333
Alice Springs 14 33333332
Gingin 22 34345432
Canberra 16 33343333
Kennaook Cape Grim 21 43444432
Hobart 21 44444332
Estimated Antarctic Regional K Indices 04 Dec :
Macquarie Island 53 45666642
Casey 50 57653434
Mawson 46 55654554
Observed Regional daily pc3 Indices 04 Dec :
Darwin 4 (Quiet)
Townsville 4 (Quiet)
Learmonth 16 (Quiet)
Alice Springs 8 (Quiet)
Gingin 105 (Major storm)
Canberra 80 (Active)
Hobart 138 (Severe 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 04 Dec : A
Fredericksburg 22
Planetary 34
Observed AFr/Ap Indices 03 Dec : A K
Fredericksburg 20
Planetary 33 2323 5475
2B. MAGNETIC FORECAST
Date Ap Conditions
05 Dec 16 G0-G1
06 Dec 12 G0
07 Dec 8 G0
COMMENT: ASWFC Geomagnetic Warning 96 was issued on 4 December
and is current for 4-5 Dec. Geomagnetic conditions in the Australian
region on UT day 4-Dec were G0, although Gingin observed an isolated
period of G1. The Antarctic region observed G0-G3 geomagnetic
conditions and the planetary average reached G1. G0 geomagnetic
conditions are expected over 5-7 Dec, although isolated periods
of G1 are possible on 5-Dec due to ongoing coronal hole effects.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
04 Dec Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
05 Dec Normal-fair Normal Normal-fair
06 Dec Normal Normal Normal-fair
07 Dec Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 4-Dec were
mostly normal, with some mild degradations in the southern hemisphere.
HF radio propagation conditions are expected to be normal over
5-7 Dec.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
04 Dec 72
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Depressed by 15% during local day.
Near predicted monthly values during local night.
Depressed by 20% after local dawn.
Southern Australian Region:
Depressed by 15% during local day.
Near predicted monthly values during local night.
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
05 Dec 85 Depressed 10 to 15%/near predicted monthly values
06 Dec 100 Near predicted monthly values
07 Dec 105 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 4-Dec were near predicted values to 15% depressed.
Sporadic-E was observed in Brisbane and Canberra during local
night hours. Spread-F was observed in Hobart. MUFs are expected
to mostly near predicted values over 5-7 Dec, mildly depressed
at the beginning of the period but improving by 6-Dec. Nighttime
sporadic-E is expected.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 03 Dec
Daily Proton Fluence >1 MeV: 4.2E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.20E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:12%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 03 Dec
Speed: 399 km/sec Density: 9.2 p/cc Temp: 45900 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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