[Ips-dsgr] ASWFC Daily Report - 21 July 25 issued 2332 UT on 21 Jul 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Jul 22 09:32:25 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 JULY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 JULY AND FORECAST FOR 22 JULY - 24 JULY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Jul: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Jul: 143/97
1B. SOLAR FORECAST
22 Jul 23 Jul 24 Jul
Activity R0,chance R1 R0,chance R1 R0,chance R1
Fadeouts Possible Possible Possible
10.7cm/SSN 138/92 135/89 135/89
COMMENT: Solar activity on UT day 21-Jul was at the R0 level,
with no significant flare activity. Solar region AR4149 (N17E50,
beta) is growing with development in its intermediate spots.
Solar region AR4143 (N23W74, beta-gamma) continues to slowly
decay as it approaches the north west solar limb. Smaller solar
region AR4150 (S15E45, beta) has shown redistribution it is very
small intermediate and trailer spots. Solar region AR4143 produced
the largest flare of the day a C5.1 flare at 21/0009UT. A slow
rise C2.8 flare was observed from 21/1930UT which appears to
be from the leader spots of solar region AR4143. Minor breaking
plasma limb arches were observed in SDO imagery in association
with this event. There are currently eight numbered sunspot regions
visible on the solar disk. Other regions are small and either
stable or in decay. A small 12 degree long solar filament located
at S30E05 erupted at 21/0237UT visible in Learmonth GONG imagery.
Solar activity is expected to be at R0, chance R1 levels over
22-24 Jul. There is a chance for an isolated low level R1 flare
from AR4149. S0 solar radiation storm conditions were observed
on UT day 21-Jul. S0 solar radiation storm conditions are expected
over 22-24 Jul. No Earth directed CMEs were observed on UT day
21-Jul. No CME appeared associated with the small filament eruption.
An eastward CME was observed from 21/1424UT and this non Earth
directed CME could not be correlated to any on disk activity.
It is quite likely that a minor CME was associated with the slow
rise C2.8 flare observed late in the UT day, however the western
limb location of this event suggests that any possible associated
CME is likely to pass well ahead of the Earth. An equatorial
coronal hole is visible to the west of the solar central meridian.
The solar wind speed continued to further decline over the UT
day 21-Jul and is now at background levels. The solar wind speed
ranged between 430 km/s and 360 km/s and is currently at around
360 km/s. The interplanetary magnetic field strength is small.
The peak total interplanetary field strength (IMF, Bt) was 7
nT and the north-south IMF component range (Bz) was +5 to -4
nT. The solar wind speed is expected to be at near background
levels for most of 22-Jul. An increase in solar wind speed is
expected from late in the UT day on 22-Jul and into 23-Jul due
to the wind stream from the equatorial coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Jul: G0
Estimated Indices 21 Jul : A K
Australian Region 0 11000000
Cocos Island 0 11000000
Darwin 1 11101001
Townsville 1 11101001
Learmonth 1 11100000
Alice Springs 1 11100000
Gingin 0 10000000
Canberra 0 01000000
Kennaook Cape Grim 0 11000000
Hobart 0 11000000
Estimated Antarctic Regional K Indices 21 Jul :
Macquarie Island 0 00000000
Casey 3 22201001
Mawson 7 32221103
Observed Regional daily pc3 Indices 21 Jul :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 15 (Quiet)
Hobart 6 (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 Jul : A
Fredericksburg 5
Planetary 4
Observed AFr/Ap Indices 20 Jul : A K
Fredericksburg 5
Planetary 5 1112 2211
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Jul 11 G0, chance of G1 late in UT day
23 Jul 19 G0-G1
24 Jul 17 G0-G1
COMMENT: ASWFC Geomagnetic Warning 56 was issued on 19 July and
is current for 22-24 Jul. G0 geomagnetic conditions were observed
in the Australian and Antarctic regions on UT day 21-Jul. G0
conditions, with a chance of G1 conditions late in the day are
expected on 22-Jul. G0-G1 conditions are expected on 23-24 Jul.
The anticipated mild increase in geomagnetic activity is due
to an equatorial coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Jul Normal Fair-normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Jul Normal Normal-fair Normal-fair
23 Jul Normal Fair Fair
24 Jul Normal Fair-normal Fair
COMMENT: HF radio propagation conditions on UT day 21-Jul were
fair to normal, with fair conditions at high latitudes. HF conditions
are expected to be fair to normal on 22-Jul. Fair conditions
are expected for middle to high latitudes over 23-24 Jul due
to anticipated mild geomagnetic activity induced by a coronal
hole high speed wind stream.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Jul 88
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Near predicted monthly values during local night.
Depressed by 20% after local dawn.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 30% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Depressed by 15% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% over the UT day.
Monthly T index:
Month T index
Jun 79
Jul 104
Aug 102
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
22 Jul 90 Depressed 10 to 15%/near predicted monthly values
23 Jul 80 Depressed 10 to 20%/near predicted monthly values
24 Jul 70 Depressed 10 to 20%/near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 21-Jul were 20% depressed to near predicted
monthly values. Spread F was observed during local night hours
at Hobart. Sporadic E was observed at Hobart and Niue. MUFs are
expected to be generally 10-20% depressed to near predicted monthly
values over 22-24 Jul, with degraded HF conditions during local
night hours during 23-24 Jul due to expected mild geomagnetic
activity induced by a coronal hole wind stream..
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Jul
Daily Proton Fluence >1 MeV: 8.0E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 7.60E+08 (high fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:27%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Jul
Speed: 409 km/sec Density: 0.1 p/cc Temp: 63600 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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