[Ips-dsgr] ASWFC Daily Report - 18 July 26 issued 2330 UT on 18 Jul 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Jul 19 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 JULY 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 JULY AND FORECAST FOR 19 JULY - 21 JULY
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 Jul: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Jul: 110/60
1B. SOLAR FORECAST
19 Jul 20 Jul 21 Jul
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts None expected None expected None expected
10.7cm/SSN 115/66 120/72 120/72
COMMENT: Solar flare activity on UT day 18-Jul was at the R0
level, with no significant flaring activity. There are currently
two numbered regions visible on the solar disk and one unnumbered
region. Active Region (AR) 4489 (S07W01, beta) is the most magnetically
complex on the disk and has been stable over the UT day. Region
4491 (S11E33, alpha) is also stable. An unnumbered region is
rotating over the eastern limb near N15E88 (alpha). This region
is possibly the return of region 4479, which produced R3 level
flare activity on its previous rotation. Solar flare activity
is expected to be at the R0 level over 19-21 Jul, with a chance
of R1. S0 solar radiation storm conditions were observed on UT
day 18-Jul. S0 solar radiation storm conditions are expected
over 19-21 Jul. No Earth-directed coronal mass ejections (CMEs)
have been observed. The solar wind speed on UT day 18-Jul decreased,
ranging from 355 to 320 km/s and is currently near 325 km/s.
The peak total interplanetary magnetic field strength (IMF, Bt)
was 5 nT and the north-south IMF component (Bz) range was -3
to +4 nT. A narrow, elongated trans-equatorial coronal hole spanning
both solar hemispheres is currently visible in the eastern solar
hemisphere, but is not expected to impact the solar wind during
the forecast period. The solar wind speed is expected to remain
at background levels over 19-21 Jul.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Jul: G0
Estimated Indices 18 Jul : A K
Australian Region 0 11000000
Cocos Island 1 01110000
Darwin 1 11100001
Townsville 1 11100011
Learmonth 1 11110010
Alice Springs 0 11000000
Gingin 0 11000000
Canberra 1 11001000
Kennaook Cape Grim 0 01001000
Hobart 0 01001000
Estimated Antarctic Regional K Indices 18 Jul :
Macquarie Island 1 01002000
Casey 4 32211000
Mawson 5 33210001
Observed Regional daily pc3 Indices 18 Jul :
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 18 Jul : A
Fredericksburg 5
Planetary 5
Observed AFr/Ap Indices 17 Jul : A K
Fredericksburg 4
Planetary 4 1111 1111
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Jul 4 G0
20 Jul 4 G0
21 Jul 5 G0
COMMENT: G0 geomagnetic conditions were observed in the planetary,
Australian and Antarctic regions on UT day 18-Jul. G0 planetary
geomagnetic conditions are expected over 19-21 Jul.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Jul Normal-fair Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Jul Normal Normal Normal
20 Jul Normal Normal Normal
21 Jul Normal Normal Normal
COMMENT: Global high-frequency (HF) radio propagation conditions
were normal to fair on UT day 18-Jul, with some degradations
observed across northern hemisphere regions. Global HF propagation
conditions are expected to be normal over 19-21 Jul.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Jul 60
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 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.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Jun 81
Jul 66
Aug 63
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Jul 60 Near predicted monthly values
20 Jul 60 Near predicted monthly values
21 Jul 60 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region on UT day 18-Jul were mostly near predicted monthly values,
with depressions up to 15% observed during local night hours
in the northern Australian region. Strong spread-F was observed
across the Australian region during local night hours. MUFs are
forecast to be near predicted monthly values over 19-21 Jul,
with some depressions possible during local night hours.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Jul
Daily Proton Fluence >1 MeV: 1.3E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 6.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 8%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B4.2
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Jul
Speed: 380 km/sec Density: 2.8 p/cc Temp: 101000 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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