[Ips-dsgr] ASWFC Daily Report - 18 August 26 issued 2330 UT on 18 Aug 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Aug 19 09:30:48 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 AUGUST 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 18 AUGUST AND FORECAST FOR 19 AUGUST - 21 AUGUST
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 18 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Aug: 125/78
1B. SOLAR FORECAST
19 Aug 20 Aug 21 Aug
Activity R0 R0 R0
Fadeouts Possible Possible Possible
10.7cm/SSN 125/78 125/78 120/72
COMMENT: Solar flare activity on UT day 18-Aug was at the R0
level, with several minor C-class flares observed. There are
currently five numbered active regions (ARs) visible on the solar
disk. AR 4507 (N05W55, beta-gamma) is the largest and most magnetically
complex region on the visible solar disk, however it has no history
of flaring above the R0 level and has decayed over the UT day.
All other ARs are either stable or in decay. Solar flare activity
is expected to be at R0-R1 levels over 19-21 Aug, due to the
size and magnetic complexity of region 4507. S0 solar radiation
storm conditions were observed on UT day 18-Aug and are expected
to remain there over 19-21 Aug. No Earth-directed coronal mass
ejections (CMEs) have been observed. A pair of west directed
CMEs are visible in SOHO imagery from 18/0948UT and 18/1412UT,
although the 2nd CME is partially obscured by the earlier one.
The first CME appears to be associated with an eruption over
the western limb from 18/0858UT, visible in GOES SUVI imagery.
The second CME appears to be associated with an eruption on the
disk at around N20W80, visible from 18/1334UT in GOES SUVI and
SDO imagery. Modelling suggests both CMEs will pass ahead of
Earth. The solar wind speed increased over the UT day due to
the early arrival of coronal hole high speed wind stream effects.
The wind speed mostly ranged between 370 km/s and 605 km/s and
is currently at around 560 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 15 nT and the north-south
IMF component (Bz) range was -11 to +12 nT. The solar wind speed
is expected to remain elevated over 19-21 Aug due to ongoing
high speed wind stream effects from a coronal hole in the southern
hemisphere, combined with the expected arrival of a further high
speed wind stream from a coronal hole in the northern hemisphere
on 20-Aug.
-----------------------------------------------------------
2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 18 Aug: G1
Estimated Indices 18 Aug : A K
Australian Region 14 33222153
Cocos Island 10 22222143
Darwin 13 33322143
Townsville 13 24222243
Learmonth 17 33322154
Alice Springs 13 23222153
Gingin 15 33211154
Canberra 12 24222143
Kennaook Cape Grim 21 34------
Hobart 16 34211154
Estimated Antarctic Regional K Indices 18 Aug :
Macquarie Island 15 35310034
Casey 16 33311154
Mawson 26 44312165
Observed Regional daily pc3 Indices 18 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 11 (Quiet)
Canberra 20 (Quiet)
Hobart 53 (Unsettled)
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 Aug : A
Fredericksburg 18
Planetary 27
Observed AFr/Ap Indices 17 Aug : A K
Fredericksburg 19
Planetary 11 2121 2344
2B. MAGNETIC FORECAST
Date Ap Conditions
19 Aug 18 G0-G1
20 Aug 16 G0-G1
21 Aug 12 G0, chance of G1
COMMENT: G1 geomagnetic conditions were observed at the planetary
level and in the Australian region on UT day 18-Aug. Due to coronal
hole high speed wind stream effects. Mostly G1 conditions were
observed in the Antarctic region, with a period of G2 observed
at Mawson. G0-G1 geomagnetic conditions are expected over 19-20
Aug due to ongoing coronal hole high speed wind stream effects,
combined with an anticipated further coronal hole enhancement
on 20-Aug. G0 conditions, with a chance of G1 are expected on
21-Aug.
-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
18 Aug Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
19 Aug Normal Normal-fair Fair
20 Aug Normal Normal-fair Fair
21 Aug Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 18-Aug were
mostly normal in the southern hemisphere, with degradations observed
in the northern hemisphere, particularly at high latitudes. HF
radio propagation conditions are expected to be mostly normal
to fair over 19-21 Aug. Due to recent and anticipated geomagnetic
conditions. Propagations conditions are expected to gradually
improve over the period.
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
18 Aug 77
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
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
Jul 75
Aug 64
Sep 61
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
19 Aug 65 Near predicted monthly values
20 Aug 65 Near predicted monthly values
21 Aug 75 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 18-Aug were near predicted monthly values. Spread
F was observed at Hobart and Townsville during local night hours,
sporadic E was also observed at Hobart during local night hours.
MUFs are expected to be near predicted monthly values over 19-21
Aug, with mild depressions possible in the southern Australian
region over 19-20 Aug due to ongoing and forecast geomagnetic
activity.
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 17 Aug
Daily Proton Fluence >1 MeV: 2.6E+05
Daily Proton Fluence >10 MeV: 2.0E+04
Daily Electron Fluence >2 MeV: 1.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.3
DSCOVR Satellite Solar Wind Day Averaged Data for 17 Aug
Speed: 336 km/sec Density: 9.4 p/cc Temp: 103000 K Bz: -2 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------
Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
More information about the ips-dsgr
mailing list