[Ips-dsgr] ASWFC Daily Report - 26 August 25 issued 2331 UT on 26 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Aug 27 09:31:00 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 AUGUST AND FORECAST FOR 27 AUGUST - 29 AUGUST
STATUS INDICATORS SOL:** RED ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Aug: R1
Flares Max Fadeout Freq. Sectors
M3.3 0030UT possible lower West Pacific
M4.5 0525UT possible lower E. Asia/Aust.
M1.0 1407UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Aug: 202/153
1B. SOLAR FORECAST
27 Aug 28 Aug 29 Aug
Activity R1-R2 R1-R2 R1-R2
Fadeouts Probable Probable Probable
10.7cm/SSN 200/152 200/152 205/156
COMMENT: Solar activity on UT day 26-Aug was at the R1 level
due to three M-class flares, the largest of which was an M4.5
flare at 26/0525UT produced by AR4197 (S17E46, beta). There are
currently thirteen numbered sunspot regions visible on the solar
disk. AR4191 (N13E05, beta-gamma) has exhibited spot development
over the UT day, particularly in its intermediate spots. AR4200
(S08E01, beta-gamma) recently appeared on the solar disk and
has shown spot growth. AR4197 has shown spot growth in both its
leader and trailer spots but has overall become less compact,
with a clear gap now separating the leader and trailer groups.
This region has also become less magnetically complex over the
UT day. AR4199 (N08E56, beta) has shown slight decay over the
24-hour period. AR4190 (N20W20, beta), AR4198 (N11E24, beta)
and AR4201 (S18E55, beta) have all shown slight growth. All other
sunspot regions are either stable or in decay. Solar activity
is expected at R1-R2 levels over 27-29 Aug. S1 solar proton conditions
were observed on UT day 26-Aug. S0-S1 solar proton conditions
are expected over 27-29 Aug due to ongoing effects from a farside
eruption on 21-Aug. Several CMEs were observed, but none are
considered geoeffective. A southeast-directed CME was observed,
visible in STEREO-A coronagraph imagery from 26/0609UT. This
CME is considered to be associated with the aforementioned M4.5
flare from AR4197. Modelling indicates this low velocity CME
does not contain a geoeffective component. A second southeast-directed
CME was observed at 26/1348UT in LASCO C2 coronagraph imagery.
Modelling indicates this CME is not Earth-directed. The solar
wind speed on UT day 26-Aug decreased, ranging from 325 to 420
km/s and is currently near 365 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 8 nT and the north-south
IMF component (Bz) range was -7 to +7 nT. The solar wind speed
is expected to remain near background levels over 27-29 Aug.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 Aug: G0
Estimated Indices 26 Aug : A K
Australian Region 4 22221001
Cocos Island 3 22221000
Darwin 7 33221112
Townsville 7 23231022
Learmonth 3 22121001
Alice Springs 4 22221001
Gingin 4 22221001
Canberra 5 22230002
Kennaook Cape Grim 4 12231001
Hobart 5 22231002
Estimated Antarctic Regional K Indices 26 Aug :
Macquarie Island 8 13143001
Casey 9 33331112
Mawson 19 26432013
Observed Regional daily pc3 Indices 26 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 12 (Quiet)
Canberra 18 (Quiet)
Hobart 30 (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 26 Aug : A
Fredericksburg 9
Planetary 10
Observed AFr/Ap Indices 25 Aug : A K
Fredericksburg 8 0112 4221
Planetary 8 1111 3322
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Aug 10 G0
28 Aug 8 G0
29 Aug 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 26-Aug. Mostly G0 geomagnetic conditions were
observed in the Antarctic region, with an isolated period of
G2 observed at Mawson. G0 geomagnetic conditions are expected
over 27-29 Aug.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Aug Normal Normal Poor(PCA)
PCA Event : 10MeV Proton/PCA Event Began 26 08 2025 2040UT and is in progress
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Aug Normal Normal Poor(PCA)
28 Aug Normal Normal Poor(PCA)
29 Aug Normal Normal Poor(PCA)
COMMENT: HF radio propagation conditions on UT day 26-Aug were
mostly normal at low and mid latitudes. A polar cap absorption
(PCA) event began on 26-Aug and is ongoing, affecting high latitude
radio communication. HF radio propagation conditions are expected
to be mostly normal over 27-29 Aug, with poor conditions at high
latitudes due to an ongoing PCA event. Shortwave fadeouts are
probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Aug 101
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Enhanced by 25% during local day.
Enhanced by 15% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 25% during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Proton event in progress, increased absorption observed.
Monthly T index:
Month T index
Jul 88
Aug 96
Sep 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 Aug 100 Near predicted monthly values
28 Aug 100 Near predicted monthly values
29 Aug 100 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 76 was issued on
25 August and is current for 25-27 Aug. Maximum usable frequencies
(MUFs) in the Australian region on UT day 26-Aug were near predicted
monthly values to 25% enhanced. MUFs are expected to be near
predicted monthly values over 27-29 Aug. Shortwave fadeouts are
probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Aug
Daily Proton Fluence >1 MeV: 3.5E+06
Daily Proton Fluence >10 MeV: 6.7E+05
Daily Electron Fluence >2 MeV: 4.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.1
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Aug
Speed: 409 km/sec Density: 3.6 p/cc Temp: 102000 K Bz: 2 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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