[Ips-dsgr] ASWFC Daily Report - 27 September 25 issued 2330 UT on 27 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Sep 28 09:30:48 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 27 SEPTEMBER AND FORECAST FOR 28 SEPTEMBER - 30 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 27 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.0 0401UT possible lower E. Asia/Aust.
M1.1 0714UT possible lower Mid East/Indian
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Sep: 164/118
1B. SOLAR FORECAST
28 Sep 29 Sep 30 Sep
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 165/119 160/114 160/114
COMMENT: Solar activity on UT day 27-Sep was R1, with three M1
level solar flares. Two flares originated from AR4227 (S18W22,
beta) and one from new region 4232 (N0E63, beta). There are a
total of eight numbered sunspots currently on the solar disk.
AR4232 has shown some slight growth over the past day, however
all other regions are either stable or in decay. Solar activity
is expected to be R0-R1 over 28-30 Sep.
No Earth directed CMEs were observed on UT day 27-Sep.
S0 solar radiation storm conditions were observed on UT day 27-Sep.
S0 solar radiation storm conditions are expected over 28-30 Sep.
The solar wind environment on UT day 27-Sep became mildly disturbed
late in the day, likely due to a small coronal hole high speed wind
stream. The solar wind speed ranged from near 400 trending to near
350 km/s. The peak total interplanetary field strength (IMF, Bt) was
10 nT and the north-south IMF component range (Bz) was +5 to -8 nT.
The solar wind is expected to return to background levels on 28-Sep and
remain quiet over 29-30 Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Sep: G0
Estimated Indices 27 Sep : A K
Australian Region 3 12011022
Cocos Island 2 11000021
Darwin 6 22111123
Townsville 4 12011122
Learmonth 4 22011122
Alice Springs 3 21011022
Gingin 3 22100022
Canberra 3 11011022
Kennaook Cape Grim 4 12111022
Hobart 4 12111022
Estimated Antarctic Regional K Indices 27 Sep :
Macquarie Island 2 01111011
Casey 12 34410033
Mawson 17 13201164
Observed Regional daily pc3 Indices 27 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 4 (Quiet)
Hobart 6 (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 27 Sep : A
Fredericksburg 7
Planetary 7
Observed AFr/Ap Indices 26 Sep : A K
Fredericksburg 6
Planetary 7 2212 2121
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Sep 8 G0
29 Sep 6 G0
30 Sep 5 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 27-Sep. G0-G2 geomagnetic conditions were observed
in the Antarctic region. G0 geomagnetic conditions are expected
over 28-30 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Sep Fair Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Sep Normal-fair Normal Normal
29 Sep Normal-fair Normal Normal
30 Sep Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 27-Sep were
mostly normal at at middle and high latitudes. Some disturbances
were observed in low latitudes due to equatorial scintillation
during local night hours. HF radio propagation conditions are
expected to be mostly normal, outside of further scintillation
events at low latitudes.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Sep 130
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 30% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 50% during local night.
Southern Australian Region:
Enhanced by 20% during local day.
Enhanced by 25% during local night.
Enhanced by 35% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 20% 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
28 Sep 120 Near to 20% above predicted monthly values
29 Sep 120 Near to 20% above predicted monthly values
30 Sep 120 Near to 20% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 85 was issued on
27 September and is current for 27-28 Sep. Maximum usable frequencies
(MUFs) in the Australian region on UT day 27-Sep were near predicted
values to 35% enhanced. Sporadic-E was observed on the eastern
side of Australian and also in Cocos Islands during local night
hours. Scintillation was observed in Niue from 0736 to 0813UT.
MUFs are expected to be near predicted values to 20 enhanced
over 28-30 Sep. Equatorial scintillation is possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Sep
Daily Proton Fluence >1 MeV: 6.3E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 4.30E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 26 Sep
Speed: 430 km/sec Density: 0.1 p/cc Temp: 51000 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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