[Ips-dsgr] ASWFC Daily Report - 25 August 25 issued 2331 UT on 25 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Aug 26 09:31:43 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 AUGUST AND FORECAST FOR 26 AUGUST - 28 AUGUST
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 Aug: R1
Flares Max Fadeout Freq. Sectors
M4.5 0524UT possible lower E. Asia/Aust.
M1.0 0907UT possible lower Mid East/Indian
M1.2 1518UT possible lower South American/
Atlantic
M1.1 1538UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Aug: 175/129
1B. SOLAR FORECAST
26 Aug 27 Aug 28 Aug
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 152/107 155/109 155/109
COMMENT: Solar activity on UT day 25-Aug was at the R1 level
due to four M-class flares, the largest of which was an M4.5
flare at 25/0524UT produced by AR4199 (N05E73, beta). There are
currently nine numbered sunspot regions visible on the solar
disk and two unnumbered regions. AR4197 (S17E61, beta-gamma-delta)
is the most magnetically complex region on the disk and has exhibited
spot development over the UT day. AR4199 recently rotated over
the eastern limb and appears stable. This region is likely the
return of AR4168 which previously produced several R1 level flares.
AR4191 (N08E20, beta) has shown decay, particularly in its intermediate
spots. AR4198 (N08E40, beta) recently appeared on the solar disk
and has shown recent decay. Two unnumbered regions are visible
on the solar disk. The first unnumbered region recently rotated
over the eastern limb near S14E78 (alpha) and appears stable.
The second unnumbered region recently appeared on the solar disk
near N08W47 (beta) and has shown mild spot growth. All other
sunspot regions are either stable or in decay. Solar activity
is expected to be at R1-R2 levels over 26-28 Aug. S0 solar proton
conditions were observed on UT day 25-Aug, though the proton
flux has been elevated just below the S1 threshold for the majority
of the UT day. S0-S1 solar proton conditions are expected over
26-28 Aug due to ongoing effects from a farside eruption on 21-Aug.
No Earth-directed CMEs have been observed. The solar wind speed
on UT day 25-Aug increased, ranging from 345 to 440 km/s and
is currently near 425 km/s. The peak total interplanetary magnetic
field strength (IMF, Bt) was 9 nT and the north-south IMF component
(Bz) range was -8 to +8 nT. The solar wind speed is expected
to remain elevated over 26-28 Aug due to coronal hole high speed
wind stream effects from a northern hemisphere coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 Aug: G0
Estimated Indices 25 Aug : A K
Australian Region 4 01103211
Cocos Island 3 12112200
Darwin 5 12102222
Townsville 4 01103212
Learmonth 4 01103211
Alice Springs 3 01102211
Gingin 3 01003211
Canberra 4 01103211
Kennaook Cape Grim 4 01103211
Hobart 4 01103211
Estimated Antarctic Regional K Indices 25 Aug :
Macquarie Island 8 00005301
Casey 11 24413211
Mawson 11 33213214
Observed Regional daily pc3 Indices 25 Aug :
Darwin 2 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 13 (Quiet)
Hobart 19 (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 25 Aug : A
Fredericksburg 9
Planetary 12
Observed AFr/Ap Indices 24 Aug : A K
Fredericksburg 5 1112 2221
Planetary 6 2211 1122
2B. MAGNETIC FORECAST
Date Ap Conditions
26 Aug 18 G0, chance of G1
27 Aug 16 G0, chance of G1
28 Aug 10 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 25-Aug. Mostly G0 geomagnetic conditions were
observed in the Antarctic region, with an isolated period of
G1 observed at Macquarie Island. G0 geomagnetic conditions are
expected over 26-28 Aug, with a chance of G1 over 26-27 Aug due
to coronal hole high speed wind stream effects from a northern
hemisphere coronal hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 Aug Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 Aug Normal Normal-fair Fair
27 Aug Normal Normal-fair Fair
28 Aug Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 25-Aug were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 26-28 Aug, with fair conditions at high
latitudes due to expected geomagnetic activity over 26-27 Aug.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 Aug 90
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Jul 88
Aug 96
Sep 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
26 Aug 100 Near predicted monthly values
27 Aug 100 Near predicted monthly values
28 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 25-Aug were near predicted
monthly values. Spread F was observed at Hobart during local
night hours. MUFs are expected to be near predicted monthly values
over 26-28 Aug. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 Aug
Daily Proton Fluence >1 MeV: 1.8E+06
Daily Proton Fluence >10 MeV: 2.6E+05
Daily Electron Fluence >2 MeV: 5.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.1
DSCOVR Satellite Solar Wind Day Averaged Data for 24 Aug
Speed: 397 km/sec Density: 3.5 p/cc Temp: 44200 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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