[Ips-dsgr] ASWFC Daily Report - 18 June 26 issued 2330 UT on 18 Jun 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Jun 19 09:30:51 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 JUNE 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 JUNE AND FORECAST FOR 19 JUNE - 21 JUNE
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 Jun: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Jun: 111/62
1B. SOLAR FORECAST
19 Jun 20 Jun 21 Jun
Activity R0 R0, chance of R1 R0, chance of R1
Fadeouts None expected Possible Possible
10.7cm/SSN 112/63 118/70 118/70
COMMENT: Solar flare activity on UT day 18-Jun was at the R0
level, with no significant flaring activity. There are currently
four numbered active regions (ARs) visible on the solar disk.
ARs 4470 (N07E43, beta-gamma) and 4471 (N17E12, beta) showed
spot development over the UT day. 4470 currently displays complex
magnetic structure, but has no flare production history above
the C-class level. All other numbered ARs are either stable or
in decay. Solar flare activity is expected to be at the R0 level
over 19-21 Jun, with a chance of R1 on 20-21 Jun due to ARs expected
to rotate over the eastern limb. S0 solar radiation storm conditions
were observed on UT day 18-Jun. S0 solar radiation storm conditions
are expected over 19-21 Jun. No Earth-directed coronal mass ejections
(CMEs) were observed on 18-Jun. A west directed fast CME is visible
in SOHO and STEREO-A imagery from 18/0624UT. This CME is a farside
event and is not considered geoeffective. The solar wind speed
decreased over 18-Jun, mostly ranging between 440 km/s and 350
km/s and is currently at around 360 km/s. IMF conditions became
slightly enhanced over the UT day, possibly due to a weak transient
CME arrival. The peak total interplanetary magnetic field strength
(IMF, Bt) was 7 nT and the north-south IMF component (Bz) range
was -7 to +2 nT. A sustained period of -Bz began at 28/2210UT
and is ongoing. A slight increase in the solar wind speed is
possible over 19-20 Jun due to a small coronal hole approaching
a geoeffective position. In general, however, solar wind conditions
are expected to be near background levels over 19-21 Jun.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Jun: G0
Estimated Indices 18 Jun : A K
Australian Region 2 21100111
Cocos Island 2 01110211
Darwin 3 21101102
Townsville 3 21211101
Learmonth 4 21101222
Alice Springs 3 11200112
Gingin 4 21100222
Canberra 2 20100101
Kennaook Cape Grim 2 11110111
Hobart 2 21100111
Estimated Antarctic Regional K Indices 18 Jun :
Macquarie Island 1 21010000
Casey 6 22221222
Mawson 20 43212454
Observed Regional daily pc3 Indices 18 Jun :
Darwin NA
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 8 (Quiet)
Canberra 9 (Quiet)
Hobart 9 (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 Jun : A
Fredericksburg 5
Planetary 6
Observed AFr/Ap Indices 17 Jun : A K
Fredericksburg 7
Planetary 6 2122 2101
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Jun 8 G0
20 Jun 8 G0
21 Jun 4 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region and at the planetary level on UT day 18-Jun. Mostly G0
conditions were observed in the Antarctic region, with a period
of G1 conditions observed at Mawson. G0 planetary geomagnetic
conditions are expected over 19-21 Jun.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Jun Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Jun Normal Normal Normal-fair
20 Jun Normal Normal Normal-fair
21 Jun Normal Normal Normal
COMMENT: High frequency propagation conditions were mostly normal
on UT day 18-Jun with some degradations at all latitudes in the
first and fourth quarters of the UT day. HF propagation conditions
are expected to be mostly normal over 19-21 Jun.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Jun 64
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.
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
May 67
Jun 68
Jul 65
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Jun 70 Near predicted monthly values
20 Jun 70 Near predicted monthly values
21 Jun 70 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) in the Australian
region were mostly near predicted monthly values on 16-Jun, with
mild depressions observed, mostly in the northern region during
local afternoon hours. Spread F was observed at Hobart during
local night hours. MUFs are expected to be near predicted monthly
values over 19-21 Jun.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Jun
Daily Proton Fluence >1 MeV: 5.0E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 3.70E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B4.0
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Jun
Speed: 450 km/sec Density: 6.9 p/cc Temp: 137000 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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