[Ips-dsgr] ASWFC Daily Report - 17 July 26 issued 2330 UT on 17 Jul 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Jul 18 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 JULY 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 JULY AND FORECAST FOR 18 JULY - 20 JULY
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Jul: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Jul: 105/54
1B. SOLAR FORECAST
18 Jul 19 Jul 20 Jul
Activity R0 R0, chance of R1 R0, chance of R1
Fadeouts None expected None expected None expected
10.7cm/SSN 110/60 115/66 120/72
COMMENT: Solar flare activity on UT day 17-Jul was at the R0
level, with no significant flaring activity. There are currently
two numbered active regions (ARs) visible on the solar disk.
Region 4489 (S07E14, beta) is the largest on the disk and was
mostly stable over the UT day. Region 4491 (S11E48, alpha) showed
some decay. An unnumbered region is visible near S17E38 (alpha)
and has shown mild spot growth. Solar flare activity is expected
to be at the R0 level on 18-Jul, increasing to R0, with a chance
of R1 over 19-20 Jul due to a new region rotating onto the visible
disk. S0 solar radiation storm conditions were observed on UT
day 17-Jul. S0 solar radiation storm conditions are expected
over 18-20 Jul. No Earth-directed coronal mass ejections (CMEs)
have been observed. An east-directed CME was observed, visible
in LASCO C2 coronagraph imagery from 17/0012UT. This CME is considered
to be a farside event and therefore not geoeffective. Similarly,
a west-directed CME observed at 17/1800UT is considered farside
and not Earth-directed. The solar wind speed on UT day 17-Jul
decreased, ranging from 430 to 350 km/s and is currently near
350 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 4 nT and the north-south IMF component (Bz) range
was -4 to +3 nT. The solar wind speed is expected to remain at
background levels over 18-20 Jul.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Jul: G0
Estimated Indices 17 Jul : A K
Australian Region 1 01101100
Cocos Island 1 01110100
Darwin 0 01100000
Townsville 2 11101101
Learmonth 3 11111210
Alice Springs 1 11100000
Gingin 2 01101200
Canberra 0 00001000
Kennaook Cape Grim 0 00001100
Hobart 1 01001100
Estimated Antarctic Regional K Indices 17 Jul :
Macquarie Island 0 00001000
Casey 5 13221210
Mawson 9 22211341
Observed Regional daily pc3 Indices 17 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 17 Jul : A
Fredericksburg 5
Planetary 5
Observed AFr/Ap Indices 16 Jul : A K
Fredericksburg 0
Planetary 0 2322 2112
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Jul 5 G0
19 Jul 4 G0
20 Jul 5 G0
COMMENT: G0 geomagnetic conditions were observed in the planetary,
Australian and Antarctic regions on UT day 17-Jul. G0 planetary
geomagnetic conditions are expected over 18-20 Jul.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Jul Normal Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Jul Normal Normal Normal
19 Jul Normal Normal Normal
20 Jul Normal Normal Normal
COMMENT: Global high-frequency (HF) radio propagation conditions
were normal to fair on UT day 17-Jul, with some degradations
observed across southern hemisphere regions. Global HF propagation
conditions are expected to be normal over 18-20 Jul.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Jul 59
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 20% during local day.
Depressed by 20% during local night.
Depressed by 20% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% 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
18 Jul 55 Near predicted monthly values
19 Jul 55 Near predicted monthly values
20 Jul 55 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region on UT day 17-Jul were mostly near predicted monthly values,
with depressions up to 20% 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 18-20 Jul,
with some depressions possible during local night hours.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Jul
Daily Proton Fluence >1 MeV: 1.1E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 4.80E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B3.3
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Jul
Speed: 457 km/sec Density: 3.3 p/cc Temp: 242000 K Bz: -2 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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