[Ips-dsgr] ASWFC Daily Report - 20 July 25 issued 2332 UT on 20 Jul 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon Jul 21 09:32:21 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 JULY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 JULY AND FORECAST FOR 21 JULY - 23 JULY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 Jul: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Jul: 150/105
1B. SOLAR FORECAST
21 Jul 22 Jul 23 Jul
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 140/94 140/94
COMMENT: Solar activity on UT day 20-Jul was at the R0 level,
with two large C-class flares, a C7.8 flare at 20/0740UT and
a C6.6 flare at 20/1636UT. There are currently ten numbered sunspot
regions visible on the solar disk and three unnumbered regions,
however these are all mostly small and magnetically simple. AR4136
(N19W79, beta-gamma) is one of the largest regions and is the
most magnetically complex, but is stable and soon to rotate off
the solar disk. Newly numbered AR4151 (N10W21, beta) and AR4143
(N23W63, beta) showed some development, but remain magnetically
simple. Three small, unnumbered regions have developed on the
solar disk with beta magnetic characteristics at N02E08, S22E10
and N03E25. All other sunspot regions are relatively small and
either stable or in decay. Solar activity is expected to be at
R0-R1 levels over 21-23 Jul. S0 solar radiation storm conditions
were observed on UT day 20-Jul. S0 solar radiation storm conditions
are expected over 21-23 Jul. No Earth directed CMEs were observed
on UT day 20-Jul. An erupting filament is visible in GOES SUVI
and H-Alpha imagery from 20/0700UT at around S27E15. An associated
CME is visible in SOHO and LASCO coronagraph imagery from 20/0800UT.
Modelling indicates this CME will pass behind Earth on 23-Jul.
The solar wind speed was in decline over the UT day 20-Jul and
is at background levels. The solar wind speed mostly ranged between
445 km/s and 365 km/s and is currently at around 400 km/s. The
peak total interplanetary field strength (IMF, Bt) was 6 nT and
the north-south IMF component range (Bz) was +5 to -5 nT. The
solar wind speed is expected to remain near background levels
over 21-Jul and the first part of 22-Jul. An increase is expected
from 22-Jul and into 23-Jul due to an equatorial coronal hole
rotating towards a geoeffective position.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Jul: Quiet
Estimated Indices 20 Jul : A K
Australian Region 2 11112100
Cocos Island 1 11111000
Darwin 4 11122111
Townsville 4 11113101
Learmonth 3 11222100
Alice Springs 2 11012101
Gingin 4 11113101
Canberra 3 01013100
Kennaook Cape Grim 3 01123100
Hobart 3 11113100
Estimated Antarctic Regional K Indices 20 Jul :
Macquarie Island 2 00022100
Casey 4 12222110
Mawson 16 23212126
Observed Regional daily pc3 Indices 20 Jul :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 13 (Quiet)
Canberra 5 (Quiet)
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 20 Jul : A
Fredericksburg 5
Planetary 5
Observed AFr/Ap Indices 19 Jul : A K
Fredericksburg 8
Planetary 7 1222 2222
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Jul 5 G0
22 Jul 8 G0, chance of G1
23 Jul 16 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 region on UT day 20-Jul. Mostly G0 conditions
were observed in the Antarctic region, with one period of G2
observed at Mawson. G0 geomagnetic conditions are expected on
21-Jul. G0 conditions, with a chance of G1 late in the day are
expected on 22-Jul. G0-G1 conditions are expected on 23-Jul.
Anticipated geomagnetic activity is due to an equatorial coronal
hole currently approaching a geoeffective position.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Jul Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Jul Normal Normal Normal
22 Jul Normal Normal Normal-fair
23 Jul Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 20-Jul were
generally normal, with fair conditions at high latitudes and
some degradations at mid latitudes during the first half of the
UT day. HF conditions are expected to be mostly normal over 21-22
Jul. Mild degradations are possible on 23-Jul due to anticipated
coronal hole high speed wind stream effects.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Jul 87
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 35% during local night.
Depressed by 30% after local dawn.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values 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
21 Jul 86 Near predicted monthly values
22 Jul 88 Near predicted monthly values
23 Jul 80 Depressed 15%/near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region were near predicted monthly values during local day and
depressed by up to 15% during local night. Spread F was observed
during local night hours at Hobart, Perth, Brisbane and Niue.
MUFs are expected to be generally near predicted monthly values
over 21-22 Jul. Conditions are expected to be near predicted
monthly values to depressed by 15% on 23-Jul due to coronal hole
high speed wind stream effects.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Jul
Daily Proton Fluence >1 MeV: 4.4E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 4.50E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:22%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.3
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Jul
Speed: 506 km/sec Density: 0.1 p/cc Temp: 109000 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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