[Ips-dsgr] ASWFC Daily Report - 11 September 25 issued 2330 UT on 11 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Sep 12 09:30:49 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/11 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 11 SEPTEMBER AND FORECAST FOR 12 SEPTEMBER - 14 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 11 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 11 Sep: 115/66
1B. SOLAR FORECAST
12 Sep 13 Sep 14 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 118/70 120/72 125/78
COMMENT: Solar activity on UT day 11-Sep was at R0. There are
currently seven numbered regions and one unnumbered region visible
on the solar disk. AR4207(N31W76,beta) was responsible for a
number of C class flares through the UT day as it rotates over
the western limb later today. AR4213 (S13W45, beta) is the largest
of the on disk regions and showed slight decay in its intermediates
and has remained flare quiet. AR4216 (N09E82, beta) has recently
rotated onto the visible solar disk. It remains stable, appears
active and is a region of interest. Proximity to the eastern
solar limb limits magnetic complexity analysis however it appears
at beta complexity at this stage. All other sunspot regions are
either stable or in decay. Solar activity is expected to be at
the R0-R1 over 12-14 Sep. A filament eruption on the northeast
solar quadrant N45E50 was observed on GOES SUVI 304 at 11/2005UT.
Due to the solar location, this event is not expected to be geoeffective.
In SDO 304 localised plasma motion was observed at S35E25-E00
in association with an active solar filament. No Earth directed
CMEs have been observed. It is possible that a faint CME is possible
associated with beyond disk filament activity at S35E25 with
a predominately south directed CME observed from 11/1026UT. Event
modelling assuming this pairing shows a CME passing under the
earth at 14/0900UT. S0 solar radiation storm conditions were
observed on UT day 11 Sep. S0 solar radiation storm conditions
are expected over 12-14 Sep. A large equatorial coronal hole
is crossing the solar central meridian. The solar wind speed
on UT day 11-Sep was moderately elevated and with a declining
trend ranging from 400 to 490 km/s and is currently near 410
km/s. The peak total interplanetary magnetic field strength (IMF,
Bt) was 9 nT and the north-south IMF component (Bz) range was
-7 to +4 nT. The solar wind speed is expected to continue to
slowly decline over 12-13 Sep due to the wind stream from the
coronal hole located in the southern western solar hemisphere
moving out of a geoeffective position. The equatorial coronal
hole is expected to increase the solar wind from late in the
UT day on 14 Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 11 Sep: G0
Estimated Indices 11 Sep : A K
Australian Region 5 22221211
Cocos Island 4 22111210
Darwin 5 22211112
Townsville 5 21221212
Learmonth 6 22222211
Alice Springs 4 12221101
Gingin 5 21221211
Canberra 4 11222101
Kennaook Cape Grim 4 11222111
Hobart 6 12232211
Estimated Antarctic Regional K Indices 11 Sep :
Macquarie Island 9 22442100
Casey 8 33221212
Mawson 30 45632325
Observed Regional daily pc3 Indices 11 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 4 (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 11 Sep : A
Fredericksburg 11
Planetary 10
Observed AFr/Ap Indices 10 Sep : A K
Fredericksburg 13
Planetary 13 4412 2212
2B. MAGNETIC FORECAST
Date Ap Conditions
12 Sep 6 G0
13 Sep 5 G0
14 Sep 13 G0, with a chance of G1 late in UT day.
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 11-Sep. In the Antarctic region G0 geomagnetic
conditions with isolated G2 conditions were observed. G0 expected
on 12-13 Sep with chance of G1 conditions late in the UT day
14-Sep. G1-G2 conditions are possible on 15-16 Sep due to anticipated
entry into coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
11 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
12 Sep Normal Normal Normal
13 Sep Normal Normal Normal
14 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 11-Sep were
fair to normal. HF radio propagation conditions are generally
expected to be fair to normal over 12-14 Sep. Conditions in the
mid to high latitudes may become degraded from 14-15 Sep. Isolated
minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
11 Sep 100
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 25% during local day.
Enhanced by 40% during local night.
Enhanced by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Aug 96
Sep 92
Oct 90
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
12 Sep 95 Near predicted monthly values
13 Sep 100 Near predicted monthly values
14 Sep 95 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the northern Australian
region on UT day 11-Sep were near predicted monthly values and
enhanced 20-40% throughout the day at Niue island. Spread F was
observed at Perth, Canberra and Hobart during local night hours.
MUFs are expected to be near predicted monthly values on 12-14
Sep. Southern Australian region MUFs may become depressed after
15-Sep due to the anticipated increase in geomagnetic activity
from coronal hole wind stream. Isolated minor shortwave fadeouts
are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 10 Sep
Daily Proton Fluence >1 MeV: 2.1E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 4.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B5.8
DSCOVR Satellite Solar Wind Day Averaged Data for 10 Sep
Speed: 500 km/sec Density: 1.6 p/cc Temp: 105000 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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