[Ips-dsgr] ASWFC Daily Report - 27 July 26 issued 2330 UT on 27 Jul 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Jul 28 09:30:50 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/27 JULY 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 27 JULY AND FORECAST FOR 28 JULY - 30 JULY
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 27 Jul: R1
Flares Max Fadeout Freq. Sectors
M1.0 0243UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Jul: 147/101
1B. SOLAR FORECAST
28 Jul 29 Jul 30 Jul
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts None expected None expected None expected
10.7cm/SSN 150/105 145/99 140/94
COMMENT: Solar flare activity on UT day 27-Jul was at the R1
level due to an M1.0 flare at 27/0243UT produced by Active Region
(AR) 4494 (S04W12, beta). There are currently six numbered regions
visible on the solar disk and one unnumbered region. Region 4494
has shown mild decay over the UT day. AR 4493 (N06W89, beta)
is currently rotating over the western limb. Newly numbered region
4498 (N12E78, alpha) recently rotated over the eastern limb and
appears stable. An unnumbered region recently appeared near N01E48
(beta) and has shown mild spot growth. All other regions are
either stable or in decay. Solar flare activity is expected to
be at the R0 level over 28-30 Jul, with a chance of R1. S0 solar
radiation storm conditions were observed on UT day 27-Jul. S0
solar radiation storm conditions are expected over 28-30 Jul.
No significantly Earth-directed coronal mass ejections (CMEs)
have been observed. A filament eruption was observed, visible
in GOES SUVI imagery from 27/0533UT. An associated CME was observed
in LASCO C2 coronagraph imagery from 27/0836UT. Modelling indicates
a glancing arrival is possible on 31-Jul, however this is not
expected to be significant. A west-directed CME visible in LASCO
C2 and STEREO-A coronagraph imagery at 27/0724UT is considered
a farside event and not geoeffective. The solar wind speed on
UT day 27-Jul decreased, ranging from 430 to 360 km/s and is
currently near 400 km/s. The peak total interplanetary magnetic
field strength (IMF, Bt) was 8 nT and the north-south IMF component
(Bz) range was -5 to +5 nT. A weak solar wind shock was observed
at 27/1528UT, indicative of a CME arrival, likely a CME associated
with a filament eruption first observed on 24-Jul. The solar
wind speed is expected to remain near background levels over
28-30 Jul.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Jul: G0
Estimated Indices 27 Jul : A K
Australian Region 2 11110111
Cocos Island 2 11110110
Darwin 3 11200212
Townsville 4 11111212
Learmonth 4 11210212
Alice Springs 2 01200111
Gingin 2 11100121
Canberra 2 11100112
Kennaook Cape Grim 3 11210111
Hobart 1 00110111
Estimated Antarctic Regional K Indices 27 Jul :
Macquarie Island 0 00110000
Casey 5 22210122
Mawson 11 31211144
Observed Regional daily pc3 Indices 27 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 27 Jul : A
Fredericksburg 6
Planetary 8
Observed AFr/Ap Indices 26 Jul : A K
Fredericksburg 8
Planetary 6 2222 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Jul 10 G0
29 Jul 8 G0
30 Jul 8 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian,
planetary and Antarctic regions on UT day 27-Jul. G0 planetary
geomagnetic conditions are expected over 28-30 Jul.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Jul Normal-fair Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Jul Normal Normal Normal-fair
29 Jul Normal Normal Normal-fair
30 Jul Normal Normal Normal-fair
COMMENT: Global high-frequency (HF) radio propagation conditions
were mostly normal on UT day 27-Jul, with mild depressions observed
in the southern hemisphere. Global HF propagation conditions
are forecast to be mostly normal over 28-30 Jul. Isolated minor
shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Jul 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 20% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Southern Australian Region:
Mostly near predicted monthly values.
Enhanced by 20% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 15% 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
28 Jul 70 Near predicted monthly values
29 Jul 70 Near predicted monthly values
30 Jul 70 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 69 was issued on
27 July and is current for 27-28 Jul. Maximum Usable Frequencies
(MUFs) in the Australian region were mostly near predicted monthly
values on UT day 27-Jul, with 15% depressions observed in the
northern Australian region during local night hours. Spread-F
was observed at Learmonth and Hobart during local night hours.
MUFs are expected to be near predicted monthly values over 28-30
Jul. Isolated minor shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Jul
Daily Proton Fluence >1 MeV: 1.6E+05
Daily Proton Fluence >10 MeV: 1.9E+04
Daily Electron Fluence >2 MeV: 5.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B9.5
DSCOVR Satellite Solar Wind Day Averaged Data for 26 Jul
Speed: 490 km/sec Density: 1.1 p/cc Temp: 144000 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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