[Ips-dsgr] ASWFC Daily Report - 27 August 25 issued 2330 UT on 27 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Aug 28 09:30:47 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 27 AUGUST AND FORECAST FOR 28 AUGUST - 30 AUGUST
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 27 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Aug: 226/176
1B. SOLAR FORECAST
28 Aug 29 Aug 30 Aug
Activity R1, chance of R2 R1, chance of R2 R1, chance of R2
Fadeouts Possible Possible Possible
10.7cm/SSN 225/175 225/175 228/178
COMMENT: Solar activity on UT day 27-Aug was at the R0 level,
with a C9.2 flare observed at 27/1250UT the largest flare of
the day. There are currently thirteen numbered sunspot regions
visible on the solar disk. AR4199 (N05E43, beta) was responsible
for the largest flare of the UT day but remained stable. AR4194
(N03W25, beta), AR4197 (S17E33, beta-gamma), AR4198 (N11E11,
beta), AR4200 (S08W12, beta), AR4201 (S18E42, beta) and AR4203
(N14E76, beta) all showed spot development over 27-Aug. AR4197
and AR4201 both currently possess possible delta spot candidates
and AR4197 is the largest and most magnetically complex region
on the solar disk. All other sunspot regions are either stable
or in decay. Solar activity is expected at the R1 level, with
a chance of R2 over 28-30 Aug. S1 solar radiation storm conditions
were observed on UT day 27-Aug, although the proton flux as measured
at GOES dropped below the S1 threshold by the end of the UT day.
S0-S1 solar radiation conditions are expected over 28-30 Aug
due to ongoing effects from a farside eruption on 21-Aug. No
geoeffective CMEs were observed on 27-Aug. A pair of narrow CMEs
were observed directed to the north and south in SOHO and STERO-A
imagery from 27/0824UT and 27/0712UT respectively, no on disk
source could be identified for these CMEs and they are not considered
geoeffective. A disappearing filament is visible from 27/1000UT
in SDO, H-Alpha and GOES SUVI imagery at around N08W38, no associated
CME is visible in available coronagraph imagery. An eruption
on disk is visible in SDO, H-Alpha and GOES SUVI imagery from
27/2004UT at around N07E10, no associated CME is visible in available
coronagraph imagery. Further analysis will be performed when
more coronagraph imagery becomse available. The solar wind speed
on UT day 27-Aug was stead at around background levels, ranging
from 330 to 415 km/s and is currently near 390 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 28-30 Aug.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Aug: G0
Estimated Indices 27 Aug : A K
Australian Region 4 11112212
Cocos Island 4 11112211
Darwin 6 22122222
Townsville 5 11112222
Learmonth 5 21112222
Alice Springs 3 00112212
Gingin 5 11112222
Canberra 3 11001212
Kennaook Cape Grim 4 11012212
Hobart 3 11002211
Estimated Antarctic Regional K Indices 27 Aug :
Macquarie Island 3 00002301
Casey 15 34423223
Mawson 18 33212155
Observed Regional daily pc3 Indices 27 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 0 (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 Aug : A
Fredericksburg 9
Planetary 10
Observed AFr/Ap Indices 26 Aug : A K
Fredericksburg 8
Planetary 0 2323 2112
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Aug 8 G0
29 Aug 6 G0
30 Aug 5 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 27-Aug. Mostly G0 geomagnetic conditions were
observed in the Antarctic region, with G1 conditions observed
at Mawson. G0 geomagnetic conditions are expected over 28-30
Aug.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Aug Normal Normal Normal-fair
PCA Event : 10MeV Proton/PCA Event Began at 2040UT 26/08, Ended at 2310UT 26/08
and, 10MeV Proton/PCA Event Began at 0100UT 27/08, Ended at 1305UT 27/08
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Aug Normal Normal Normal-fair
29 Aug Normal Normal Normal
30 Aug Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 26-Aug were
mostly normal at low and mid latitudes. A polar cap absorption
(PCA) event was ongoing from 27/0100 to 27/1305UT, affecting
high latitude radio communication. HF radio propagation conditions
are expected to be mostly normal over 28-30 Aug, with poor conditions
possible at high latitudes due to the chance of further S1 events.
Brief shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Aug 102
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Mostly near predicted monthly values.
Northern Australian Region:
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
28 Aug 110 Near predicted monthly values
29 Aug 110 Near predicted monthly values
30 Aug 110 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 77 was issued on
27 August and is current for 27-29 Aug. Maximum usable frequencies
(MUFs) in the Australian region on UT day 27-Aug were near predicted
monthly values. MUFs are expected to be near predicted monthly
values over 28-30 Aug. Brief shortwave fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Aug
Daily Proton Fluence >1 MeV: 7.0E+06
Daily Proton Fluence >10 MeV: 7.6E+05
Daily Electron Fluence >2 MeV: 1.20E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C2.8
DSCOVR Satellite Solar Wind Day Averaged Data for 26 Aug
Speed: 390 km/sec Density: 2.8 p/cc Temp: 82300 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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