[Ips-dsgr] ASWFC Daily Report - 28 September 25 issued 2330 UT on 28 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon Sep 29 09:30:49 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/28 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 28 SEPTEMBER AND FORECAST FOR 29 SEPTEMBER - 01 OCTOBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 28 Sep: R2
Flares Max Fadeout Freq. Sectors
M6.4 0843UT probable lower Mid East/Indian
Observed 10.7 cm flux/Equivalent Sunspot Number for 28 Sep: 171/125
1B. SOLAR FORECAST
29 Sep 30 Sep 01 Oct
Activity R0-R1, chance R2 R0-R1, chance R2 R0-R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 175/129 180/133 180/133
COMMENT: Solar activity on UT day 28-Sep was R2 with an M6 solar
from AR4232 (N05E51, beta) and an M1 solar from AR4233 (N19E54,
beta). There are currently nine numbered sunspot regions on the
solar disk. There is a cluster of sunspots on the eastern limb
that are currently all in a growth phase with AR4232 being the
most complex and flare active of them. All other sunspot regions
are decaying. Solar activity is expected to be R0-R1 with isolated
R2 flares possible over 29-30 Sep and 1-Oct.
A CME was associated with the M6 solar flare and can be seen
from 0912 UT directed to the solar east, but is not considered
geoeffective. Several other CMEs were observed from the vicinity
of this active region but none were analysed as geoeffective.
S0 solar radiation storm conditions were observed on UT day 28-Sep.
S0 solar radiation storm conditions are expected over 29-30 Sep and 1-Oct.
On UT day 28-Sep the solar wind environment was mildly disturbed due
to a small coronal hole. The solar wind speed ranged from 447
to 378 km/s and is currently steady. The peak interplanetary
magnetic field strength (IMF, Bt) was 14 nT and the north-south
IMF component range (Bz) was +13 to -7 nT. The solar wind is
expected to be near background levels over 29-30 Sep and 1-Oct.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 28 Sep: G0
Estimated Indices 28 Sep : A K
Australian Region 8 32122322
Cocos Island 5 22121221
Darwin 8 32122322
Townsville 8 32122322
Learmonth 9 32122323
Alice Springs 8 32122322
Gingin 9 32221323
Canberra 7 22122322
Kennaook Cape Grim 7 22122322
Hobart 7 22112322
Estimated Antarctic Regional K Indices 28 Sep :
Macquarie Island 4 21011221
Casey 19 45431323
Mawson 15 44121334
Observed Regional daily pc3 Indices 28 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 4 (Quiet)
Canberra 6 (Quiet)
Hobart 13 (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 28 Sep : A
Fredericksburg 10
Planetary 12
Observed AFr/Ap Indices 27 Sep : A K
Fredericksburg 5
Planetary 6 2211 1132
2B. MAGNETIC FORECAST
Date Ap Conditions
29 Sep 8 G0
30 Sep 6 G0
01 Oct 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 28-Sep. G0-G1 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 29-30 Sep to 1-Oct.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
28 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
29 Sep Normal Normal Normal
30 Sep Normal Normal Normal
01 Oct Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 28-Sep were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 28-29 Sep and 1-Oct.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
28 Sep 136
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 45% during local day.
Enhanced by 65% during local night.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 50% during local night.
Enhanced by 25% after local dawn.
Southern Australian Region:
Enhanced by 25% during local day.
Enhanced by 30% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values 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
29 Sep 130 Near to 30% above predicted monthly values
30 Sep 130 Near to 30% above predicted monthly values
01 Oct 130 Near to 30% above monthly predicted values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region were enhanced up to 50%. MUFs are expected to be near
predicted values to 30% enhanced over 29-30 Sep to 1-Oct.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 27 Sep
Daily Proton Fluence >1 MeV: 1.3E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 5.30E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 27 Sep
Speed: 376 km/sec Density: 1.9 p/cc Temp: 41900 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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