[Ips-dsgr] ASWFC Daily Report - 21 August 25 issued 2330 UT on 21 Aug 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Aug 22 09:30:45 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 AUGUST 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 AUGUST AND FORECAST FOR 22 AUGUST - 24 AUGUST
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Aug: 121/73
1B. SOLAR FORECAST
22 Aug 23 Aug 24 Aug
Activity R0, chance R1 R0, chance R1 R0, chance R1
Fadeouts None expected None expected None expected
10.7cm/SSN 125/78 125/78 130/84
COMMENT: Solar activity on UT day 21-Aug was at the R0 level,
with no significant flaring activity. There are currently five
numbered sunspot regions visible on the solar disk. AR4191 (N13E65,
beta) is the largest region on the disk and appears stable. AR4189
(N07E20, beta) has shown mild spot growth over the UT day. All
other sunspot regions are either stable or in decay. Solar activity
is expected to be at the R0 level over 22-24 Aug, with a chance
of R1. S0 solar proton conditions were observed on UT day 21-Aug.
S0 solar proton conditions are expected over 22-24 Aug. No Earth-directed
CMEs have been observed. A high velocity halo CME was observed,
visible in LASCO C2 coronagraph imagery from 21/0824UT. This
CME has no obvious on-disk source and is considered a farside
event. The solar wind speed on UT day 21-Aug declined, ranging
from 430 to 570 km/s and is currently near 455 km/s. The peak
total interplanetary magnetic field strength (IMF, Bt) was 7
nT and the north-south IMF component (Bz) range was -5 to +7
nT. A coronal hole is currently visible in the eastern solar
hemisphere, now approaching the central meridian. The solar wind
speed is expected to decline toward background levels over 22-24
Aug due to waning coronal hole high speed wind stream effects.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Aug: G0
Estimated Indices 21 Aug : A K
Australian Region 5 22110231
Cocos Island 5 12110231
Darwin 6 22210232
Townsville 6 22110232
Learmonth 6 22120231
Alice Springs 5 22110231
Gingin 5 22110231
Canberra 5 22110231
Kennaook Cape Grim 5 22110231
Hobart 5 22110231
Estimated Antarctic Regional K Indices 21 Aug :
Macquarie Island 3 22000121
Casey 9 33221232
Mawson 21 35111236
Observed Regional daily pc3 Indices 21 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 17 (Quiet)
Canberra 28 (Quiet to unsettled)
Hobart 8 (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 21 Aug : A
Fredericksburg 7
Planetary 8
Observed AFr/Ap Indices 20 Aug : A K
Fredericksburg 12 3332 3223
Planetary 13 4333 2223
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Aug 8 G0
23 Aug 6 G0
24 Aug 6 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 21-Aug. Mostly G0-G1 geomagnetic conditions
were observed in the Antarctic region, with an isolated period
of G2 observed at Mawson. G0 geomagnetic conditions are expected
over 22-24 Aug.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Aug Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Aug Normal Normal Normal-fair
23 Aug Normal Normal Normal
24 Aug Normal Normal Normal
COMMENT: HF radio propagation conditions on UT day 21-Aug were
mostly normal. HF radio propagation conditions are expected to
be mostly normal over 22-24 Aug.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Aug 93
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
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
22 Aug 90 Near predicted monthly values
23 Aug 90 Near predicted monthly values
24 Aug 90 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 21-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 22-24 Aug.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Aug
Daily Proton Fluence >1 MeV: 1.3E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 1.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.6
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Aug
Speed: 588 km/sec Density: 1.3 p/cc Temp: 163000 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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