[Ips-dsgr] ASWFC Daily Report - 22 September 25 issued 2339 UT on 22 Sep 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Sep 23 09:39:40 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/22 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 22 SEPTEMBER AND FORECAST FOR 23 SEPTEMBER - 25 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 22 Sep: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 22 Sep: 172/126
1B. SOLAR FORECAST
23 Sep 24 Sep 25 Sep
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts Possible Possible Possible
10.7cm/SSN 172/126 168/122 165/119
COMMENT: Solar activity on UT day 22-Sep was at the R0 level.
There are currently ten numbered and one unnumbered sunspot regions
on the solar disk. Of note, AR4217 (S14W38, beta) has shown some
development in leader spots and mixed development in the trailer
spots. AR4226 (S11E44, beta) has shown growth in the trailer
spots. Unnumbered region (S13E78, beta) has just rotated onto
the visible solar disk and appears to have beta magnetic classification.
Other solar regions on the visible solar disk are either stable
or in decay. Solar activity is expected to be at the R0 level
with a chance of R1 over 23-25 Sep. No Earth-directed CMEs have
been observed. A narrow finger of plasma ejecta on the NE limb
was visible around 22/1352UT on GOES SUVI 304. The activity on
the northeast limb appears to be associated with a northward
non-Earth directed CME just becoming visible in LASCO C2. S0
solar radiation storm conditions were observed on UT day 22-Sep.
S0 solar radiation storm conditions are expected over 23-25 Sep.
A moderately sized isolated coronal hole is visible in the northwestern
solar quadrant with centre at approximately N25W40. The solar
wind on UT day 22-Sep increased gradually through the UT day.
The solar wind speed ranged from 300 km/s to 560 km/s and is
currently at 510 km/s. The peak total interplanetary field strength
(IMF, Bt) was 19 nT and the north-south IMF component (Bz) range
was +17 to -13 nT. The solar wind is expected to remain elevated
throughout the UT day due to coronal hole high speed wind stream
effects and start to decline from 24-Sep. The US GOES geosynchronous
satellite 2MeV energy electron detector was elevated above the
1000 flux units threshold from 22/1200-2100UT. An elevated 2MeV
electron flux is statistically associated with an increased risk
of geosynchronous satellite anomalies.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 22 Sep: G0
Estimated Indices 22 Sep : A K
Australian Region 11 32223233
Cocos Island 9 32223222
Darwin 13 33233233
Townsville 13 32333233
Learmonth 11 32223233
Alice Springs 10 32223223
Gingin 11 32223233
Canberra 10 32223223
Kennaook Cape Grim 10 22223233
Hobart 9 23223123
Estimated Antarctic Regional K Indices 22 Sep :
Macquarie Island 8 22124122
Casey 22 44543233
Mawson 16 33322344
Observed Regional daily pc3 Indices 22 Sep :
Darwin 4 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 6 (Quiet)
Canberra 20 (Quiet)
Hobart 37 (Quiet to unsettled)
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 22 Sep : A
Fredericksburg 11
Planetary 14
Observed AFr/Ap Indices 21 Sep : A K
Fredericksburg 6
Planetary 6 2121 2211
2B. MAGNETIC FORECAST
Date Ap Conditions
23 Sep 15 G0, chance of G1
24 Sep 11 G0
25 Sep 10 G0
COMMENT: ASWFC Geomagnetic Warning 70 was issued on 19 September
and is current for 22-23 Sep. G0 geomagnetic conditions were
observed in both the Australian and Antarctic regions with an
isolated period of G1 observed at Casey for 22-Sep. Periods of
G1 geomagnetic activity are possible for 23-Sep due to coronal
hole high speed wind stream effects. G0 conditions are forecast
over 24-25 Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
22 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
23 Sep Normal Normal Normal-fair
24 Sep Normal Normal Normal-fair
25 Sep Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 22-Sep were
normal. HF radio propagation conditions are expected to be mostly
normal over 23-25 Sep noting there has been no observed degradation
due to coronal hole high speed wind stream effects on UT day
22-Sep. Isolated minor shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
22 Sep 128
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Mostly near predicted monthly values.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Southern Australian Region:
Enhanced by 20% during local day.
Enhanced by 30% during local night.
Antarctic Region (Casey/Davis/Mawson):
Enhanced 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
23 Sep 120 Near to 15% above predicted monthly values
24 Sep 110 Near to 15% above predicted monthly values
25 Sep 110 Near to 15% above predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 22-Sep were near predicted values to 30% enhanced.
MUFs are expected to be near predicted values to enhanced by
15% over 23-25 Sep. Isolated minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 21 Sep
Daily Proton Fluence >1 MeV: 7.6E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 1.40E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:13%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 21 Sep
Speed: 316 km/sec Density: 7.7 p/cc Temp: 22200 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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