[Ips-dsgr] ASWFC Daily Report - 18 June 25 issued 2330 UT on 18 Jun 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Jun 19 09:30:52 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 JUNE 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 JUNE AND FORECAST FOR 19 JUNE - 21 JUNE
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 18 Jun: R1
Flares Max Fadeout Freq. Sectors
M1.5 0000UT possible lower West Pacific
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Jun: 137/91
1B. SOLAR FORECAST
19 Jun 20 Jun 21 Jun
Activity R1,chance R2 R1,chance R2 R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 140/94 140/94
COMMENT: Solar activity on UT day 18-Jun was R1, due to an M1
flare from AR4117 (S16E64, beta-gamma). This medium sized region
has recently rotated onto the solar disk. There are now two regions
of note on the visible solar disk, AR4117 and AR4114. Solar region
AR4114 (N18W23, beta-gamma) is the largest and most significant
of the on disk regions, with some recent redevelopment in its
intermediate spots and there may be a very weak/small delta spot
in the intermediate spots of this region, however this region
may be starting to decay, with the background solar X-ray flux
declining over the past 24 hours. Solar region AR4117 currently
exhibits are more open spot configuration with some growth evident,
though is currently quite close to the southeast solar limb.
Other sunspot groups are small. There are currently six numbered
sunspot groups on the visible solar disk and one unnumbered small
new region in the western solar hemisphere. All other sunspots
are either stable or in decay. Solar activity is expected to
be R1 with a chance for R2 over 19-21 Jun, due to AR4114 and
AR4117. No significant Earth directed CMEs have been observed.
A west directed CME was observed from 18/0500UT in LASCO C2 but
is considered a far side event due to the lack of on disk activity,
possibly associated with western limb plasma spray activity visible
in GOES SUVI 304 imagery from 18/0428UT. S0 solar radiation storm
conditions were observed on UT day 18-Jun. S0 solar radiation
storm conditions are expected over 19-21 Jun. The solar wind
environment on UT day 18-Jun was moderately elevated and mostly
steady. The solar wind speed ranged from 585 to 435 km/s, and
is currently at 520 km/s. The peak total interplanetary field
strength (IMF, Bt) was 10 nT and the north-south IMF component
range was +8 to -7 nT. The solar wind has been recently moderately
elevated due to a large coronal hole in the southern solar hemisphere,
that has now rotated into the southwest solar quadrant. A weak
glancing blow CME may possibly arrive early on 20-Jun.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Jun: G0
Estimated Indices 18 Jun : A K
Australian Region 5 21222211
Cocos Island 4 21122111
Darwin 8 22232222
Townsville 8 22232222
Learmonth 6 22222221
Alice Springs 5 21222211
Gingin 6 22222221
Canberra 5 11222211
Kennaook Cape Grim 6 21232111
Hobart 5 11232111
Estimated Antarctic Regional K Indices 18 Jun :
Macquarie Island 9 21244110
Casey 10 33331222
Mawson 24 64433232
Observed Regional daily pc3 Indices 18 Jun :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 8 (Quiet)
Hobart 2 (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 14
Planetary 17
Observed AFr/Ap Indices 17 Jun : A K
Fredericksburg 9
Planetary 9 2222 3223
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Jun 15 G0, chance G1
20 Jun 18 G0, chance G1
21 Jun 10 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 18-Jun. G0-G2 geomagnetic conditions were observed
in the Antarctic region. G0, chance G1 geomagnetic conditions
are expected over 19-20 Jun, due effects from an ongoing coronal
hole wind stream with the possibility of weak glancing blow CME
arrival early in the UT day 20-Jun.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Jun Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Jun Normal Fair-normal Fair
20 Jun Normal Fair-normal Fair
21 Jun Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 18-Jun were
fair at middle to high latitudes. HF radio propagation conditions
are expected to be fair at middle to high latitudes for 19-20
Jun, with improved HF conditions on 21-Jun. Isolated fadeouts
are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Jun 93
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Depressed by 35% during local night.
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 20% during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 20% over the UT day.
Monthly T index:
Month T index
May 94
Jun 109
Jul 107
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Jun 90 Depressed 10 to 15%/near predicted monthly values
20 Jun 90 Depressed 10 to 15%/near predicted monthly values
21 Jun 105 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 66 was issued on
16 June and is current for 17-19 Jun. Maximum usable frequencies
(MUFs) in the Australian region on 18-Jun were near predicted
monthly values during the local day. Northern Australian region
MUFs were 20% depressed during local night hours. Spread F was
observed during local night hours in the southern Australian
region. MUFs are expected to be mildly depressed by 15% to near
predicted values for 19-20 Jun and near predicted monthly values
on 21-Jun, with mildly degraded HF conditions during local night
hours. Isolated fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Jun
Daily Proton Fluence >1 MeV: 1.2E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 4.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.8
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Jun
Speed: 467 km/sec Density: 8.0 p/cc Temp: 196000 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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