[Ips-dsgr] ASWFC Daily Report - 29 September 25 issued 2339 UT on 29 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Sep 30 09:39:45 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/29 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 29 SEPTEMBER AND FORECAST FOR 30 SEPTEMBER - 02 OCTOBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 29 Sep: R1
Flares Max Fadeout Freq. Sectors
M3.6 0145UT possible lower West Pacific
M1.0 1115UT possible lower European
M1.1 1139UT possible lower European
M1.0 1159UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 29 Sep: 186/139
1B. SOLAR FORECAST
30 Sep 01 Oct 02 Oct
Activity R1,chance R2 R1,chance R2 R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 180/133 180/133 175/129
COMMENT: Solar activity on UT day 29-Sep was at the R1 level.
Solar region AR4232 (N05E40, beta) produced an impulsive the
M3.6 flare and an M1.1 flare later in the UT day. Solar region
AR4236 (N12E34, beta) and AR4233 (N19E42, beta) each produced
M1 class flare events. Solar region AR4236 is rapidly growing,
and AR4230 (S10W20, beta) and AR4233 are growing. There has been
an increase in small surrounding spots in region AR4232 (N05E40,
beta). Smaller solar region AR4238 (S16W24, beta) to the south
of AR4230 is also growing. There are currently ten numbered sunspot
regions on the solar disk. All other sunspot regions are stable
or in decaying. A faint 25 degree long filament with centre located
at N25W27 erupted from 29/0836UT. Solar activity is expected
to be R1 with isolated R2 flares possible over 30 Sep to 02-Oct.
No significantly Earth directed CMEs were observed. No CME appeared
to be associated with the filament eruption in the northwest
solar quadrant. A narrow CME to the southeast and east followed
the M3.6 flare from AR4232 from 29/0212UT. A second narrow CME
to the southeast was observed from 29/1500UT which appeared to
associated with plasma ejecta from AR4232. Neither of these CMEs
are considered to have an Earth directed component. S0 solar
radiation storm conditions were observed on UT day 29-Sep. S0
solar radiation storm conditions are expected over 30 Sep to
02-Oct. On UT day 29-Sep the solar wind speed was moderately
elevated and steady. The solar wind speed ranged from 420 to
380 km/s and is currently at 400 km/s. The peak interplanetary
magnetic field strength (IMF, Bt) was 15 nT and the north-south
IMF component range (Bz) was +2to -12 nT. A prolonged interval
of mildly southward IMF conditions was observed 29/0100-2000UT.
The solar wind is expected to further slowly decline to near
background levels over the next two days. Two isolated coronal
holes currently located in the eastern solar hemisphere are approaching
the solar central meridian, with 27 day recurrence patterns suggesting
a increase in solar wind speed from 03-Oct.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 29 Sep: G1
Estimated Indices 29 Sep : A K
Australian Region 19 22254442
Cocos Island 12 22233432
Darwin 15 22243433
Townsville 20 22254443
Learmonth 24 32255443
Alice Springs 19 22254442
Gingin 27 22265443
Canberra 22 22254542
Kennaook Cape Grim 27 22265532
Hobart 28 22265542
Estimated Antarctic Regional K Indices 29 Sep :
Macquarie Island 51 12366762
Casey 16 32344332
Mawson 20 33433353
Observed Regional daily pc3 Indices 29 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 4 (Quiet)
Hobart 14 (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 29 Sep : A
Fredericksburg 14
Planetary 18
Observed AFr/Ap Indices 28 Sep : A K
Fredericksburg 9
Planetary 10 3312 2332
2B. MAGNETIC FORECAST
Date Ap Conditions
30 Sep 6 G0
01 Oct 6 G0
02 Oct 13 G0, chance G1 late in the UT day
COMMENT: G1 geomagnetic conditions were observed in the Australian
region on UT day 29-Sep associated with a sustained period of
mildly southward orientated interplanetary magnetic field conditions.
In the Antarctic region G3 geomagnetic conditions were observed
at Macquarie Island, G1 conditions were observed at Mawson and
G0 conditions were observed at Casey. Planetary G1 conditions
were observed for three Kp periods. G0 geomagnetic conditions
are expected over 30 Sep to 1-Oct, with possible G1 periods late
in the UT day on 02-Oct due to a coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
29 Sep Normal Normal-fair Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
30 Sep Normal Fair-normal Fair
01 Oct Normal Normal Normal
02 Oct Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 29-Sep were
fair to normal, with degraded HF conditions at times for high
latitudes. Increased absorption of up to 3db was observed on
the 30MHz riometer at Macquarie Island during the period 29/1600-1900UT.
HF radio propagation conditions are expected to be fair to middle
to high latitudes for 30-Sep, with normal conditions expected
for 01-Oct and most of 02-Oct. HF conditions at middle to high
latitudes may become degraded late in the UT day on 02-Oct and
into 03-Oct.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
29 Sep 130
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Niue Island Region:
Enhanced by 20-30%.
Northern Australian Region:
Enhanced by 15-25%.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Depressed by 15-30% after local dawn.
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
30 Sep 75 Depressed 15 to 20%/near predicted monthly values
01 Oct 130 Near to 15% above predicted monthly values
02 Oct 130 Near to 15% above predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 86 was issued on
28 September and is current for 29 Sep to 1 Oct. Maximum usable
frequencies (MUFs) in the Australian region on UT day 29-Sep
were variable. Northern Australian region were generally enhanced
15-25%. MUFs in the southern Australian region were initially
near to 20% above predicted monthly values, becoming depressed
by 15-30% after local dawn this morning, following overnight
geomagnetic activity and are expected to slowly recover today.
Spread F was observed at Hobart over night. Equatorial range
spread F was observed at Cocos Island and Niue. Equatorial ionospheric
scintillation was observed 29/0717-1130UT. A brief fadeout impacting
only the lower HF frequencies was observed 29/0143-0149UT. Northern
region MUFs are expected to be near predicted monthly values
to 15% enhanced for 30-Sep. MUFs are expected to be near predicted
values to 15% enhanced over 01-02 Oct.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 28 Sep
Daily Proton Fluence >1 MeV: 9.4E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.6
DSCOVR Satellite Solar Wind Day Averaged Data for 28 Sep
Speed: 408 km/sec Density: 2.6 p/cc Temp: 59200 K Bz: 5 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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