[Ips-dsgr] ASWFC Daily Report - 09 December 25 issued 2330 UT on 09 Dec 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Dec 10 10:30:51 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/09 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 09 DECEMBER AND FORECAST FOR 10 DECEMBER - 12 DECEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 09 Dec: R1
Flares Max Fadeout Freq. Sectors
M2.0 0058UT possible lower West Pacific
M1.0 0730UT possible lower Mid East/Indian
M1.6 0747UT possible lower Mid East/Indian
M1.5 1514UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 09 Dec: 183/136
1B. SOLAR FORECAST
10 Dec 11 Dec 12 Dec
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 180/133 175/129 160/114
COMMENT: On UT day 9-Dec solar activity was at the R1 level.
Solar region AR4299 (N23W34, beta) produced an M2.0 flare at
09/0058UT, the largest flare for the day. This region has now
significantly decayed. Solar region AR4294 (S15W55, beta-gamma)
produced three M1 class flares. This region continues to slowly
decay, with the larger trailer spots and some intermediate spots
remaining. Nearby solar region AR4296 (S14W41, beta) is also
slowly decaying. Other regions are small. Small solar region
AR4304 (N25W21, beta) continues to grow. A small solar region
has recently emerged in the southeast solar quadrant and has
been numbered AR4305 (S24E38, beta-gamma). This region is currently
rapidly growing. There are currently eight numbered regions on
the visible solar disk. All other sunspot regions are either
stable or in decay. Solar activity is expected to be R1-R2 over
10-12 Dec. A faint westward partially Earth directed CME was
observed from 08/2324UT, possibly associated with an M1 flare
from AR4299. A weak glancing blow arrival is possible from this
CME on 12/1300UT +/- 12 hours. A faint slow southwest CME was
observed from 09/0236UT possibly in association with flare activity
from AR4294 but subsequent modelling indicated it was insignificant.
LASCO C2 imagery was available up to 09/1100UT. S0 solar radiation
storm conditions were observed on UT day 9-Dec. S0 solar radiation
storm conditions are expected over 10-12 Dec. The anticipated
CME arrival on 09-Dec may have possibly arrived. There is a small
step discontinuity in the total interplanetary magnetic field
at 09/0756UT, which may indicate a very weak arrival and that
the CME has largely missed the Earth's magnetosphere. It is possible
that the CME may still arrive in the next 24 hours, however the
ACE EPAM CME arrival precursor low energy ion channel does not
currently show an increasing flux trend, only becoming mildly
elevated after 09/1310UT then flattening off and not subsequently
steadily increasing which can typically indicate the approach
of a more direct/halo CME. If there is a later arrival it is
expected to be weaker as the CME would be travelling more slowly.
Low confidence CMEs arrivals are possible on 11-Dec from minor/weak
CMEs observed early in the UT day on 08-Dec. In addition, a glancing
blow arrival is expected on 12-Dec from CME activity on 08-Dec
associated with an X1 flare and an earlier filament eruption.
On UT day 9-Dec the solar wind speed was light and steady and
ranged from 395 km/s to near 353 km/s and is currently at 353
km/s. The peak total interplanetary field strength (IMF, Bt)
was 9 nT and the north-south IMF component range (Bz) was -5
to +1 nT. The IMF Bz component was mildly southward over the
UT day. A coronal hole is visible in the northeast solar quadrant
and is approaching the solar central meridian. The Earth is expected
to enter the wind stream from this hole over 13-14 Dec.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 09 Dec: G0
Estimated Indices 09 Dec : A K
Australian Region 3 10111112
Cocos Island 2 11111100
Darwin 5 20122122
Townsville 4 11112122
Learmonth 5 2-122112
Alice Springs 4 20112112
Gingin 4 20111122
Canberra 3 10211112
Kennaook Cape Grim 4 10221112
Hobart 4 10221112
Estimated Antarctic Regional K Indices 09 Dec :
Macquarie Island 3 20112111
Casey 13 34333222
Mawson 15 33233343
Observed Regional daily pc3 Indices 09 Dec :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 0 (Quiet)
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 09 Dec : A
Fredericksburg 36
Planetary 55
Observed AFr/Ap Indices 08 Dec : A K
Fredericksburg 1
Planetary 2 0100 0011
2B. MAGNETIC FORECAST
Date Ap Conditions
10 Dec 18 G0, G1 conditions possible
11 Dec 10 G0,slight chance G1
12 Dec 16 G0,chance G1
COMMENT: ASWFC Geomagnetic Warning 97 was issued on 6 December
and is current for 9-10 Dec. G0 geomagnetic conditions were observed
in the Australian and Antarctic regions on UT day 9-Dec. G3 geomagnetic
storm conditions expected on UT day 9-Dec have failed to eventuate,
with only a possible very weak CME signature evident in the interplanetary
magnetic field. G1 geomagnetic conditions are possible on 10-Dec
if the expected CME has not already arrived. G0, chance G1 conditions
are possible over 11-12 Dec due to the arrival of a number of
minor/glancing CMEs recently observed.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
09 Dec Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
10 Dec Normal Normal-fair Fair
11 Dec Normal Normal-fair Fair
12 Dec Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 9-Dec were
normal. Expected degraded HF conditions associated with CME induced
geomagnetic activity did not eventuate. HF radio propagation
conditions are now considered more likely to be generally normal
for 10-Dec with mild degradations at middle to high latitudes
on 11-12 Dec in association with possible mild geomagnetic activity.
Minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
09 Dec 154
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 50% during local night.
Enhanced by 25% 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 20% during local night.
Enhanced by 25% after local dawn.
Southern Australian Region:
Enhanced by 25% during local day.
Enhanced by 20% during local night.
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
10 Dec 120 10 to 15% above predicted monthly values
11 Dec 120 10 to 15% above predicted monthly values
12 Dec 120 10 to 15% above predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 117 was
issued on 6 December and is current for 9-10 Dec. ASWFC SWF HF
Communications Warning 120 was issued on 9 December and is current
for 9-11 Dec. Maximum usable frequencies (MUFs) in the Australian
region on UT day 9-Dec were near predicted values to 25% enhanced.
Sporadic-E was observed at Niue. Mild spread F was observed at
Hobart during local night hours. Due to the failed occurrence
of CME induced geomagnetic storm activity on 09-Dec the middle
latitude Australian ionosphere is now generally expected to remain
at near predicted monthly values to 15% enhanced over 10-12 Dec.
The southern Australian region may experience mildly degraded
HF conditions during local night hours 11-12 Dec. Minor shortwave
fadeouts were observed 09/0043-0129UT and 09/0135-0142UT. Minor
shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 08 Dec
Daily Proton Fluence >1 MeV: 5.5E+06
Daily Proton Fluence >10 MeV: 2.2E+04
Daily Electron Fluence >2 MeV: 6.20E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 8%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.4
DSCOVR Satellite Solar Wind Day Averaged Data for 08 Dec
Speed: 375 km/sec Density: 0.4 p/cc Temp: 100000 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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