[Ips-dsgr] ASWFC Daily Report - 28 April 25 issued 2331 UT on 28 Apr 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue Apr 29 09:31:16 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/28 APRIL 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 28 APRIL AND FORECAST FOR 29 APRIL - 01 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 28 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 28 Apr: 154/109
1B. SOLAR FORECAST
29 Apr 30 Apr 01 May
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 155/109 155/109 160/114
COMMENT: Solar activity on UT day 28-Apr was at the R0 level.
A new region AR4079 (N08E75, alpha) is rotating onto the solar
disk. This may be the return of previously flare active AR4055,
which produced frequent R1-Minor flare activity on its past transit.
At present the visible spots of AR4079 appear to be of the same
magnetic polarity, however these may be leader spots and trailer
spots could possibly follow the currently visible spots onto
the solar disk. The solar background X-ray flux level does not
currently show an increasing trend as AR4079 rotates onto the
disk. Most of the on disk regions are small and of simple magnetic
classifications. Of the larger existing on disk regions, solar
region AR4072 (S17E04, beta) has shown slight growth and AR4076
(N06E20, alpha) is a stable monopole. The intermediate spots
of solar region AR4070 (S13W35, beta) have slightly decayed.
Solar regions AR4069 (S09W65, alpha) and AR4078 (N15W42, alpha)
each produced a minor low level C class flare. There are currently
ten numbered sunspot regions visible on the solar disk. All other
sunspot regions are either stable or in decay. A small partial
filament lift off was observed at 28/0800UT located at S30W30.
Another small 10 degree long filament erupted over the interval
28/1357-1509UT located at N08W12. Solar activity is expected
to be at the R0-R1 level over 29-Apr to 01-May. S0 solar radiation
storm conditions were observed on UT day 28-Apr. S0 solar radiation
storm conditions are expected over 29-Apr to 01-May. No Earth
directed CMEs are considered to have been observed. A northwest
directed CME was observed from 28/1325UT in LASCO C2, however
this is not considered associated with the small on disk filament
eruption located at N08W12 observed from 28/1357UT in GONG Cerro
Tololo H-alpha imagery as this CME was already visible in C2
imagery before the small filament began lifting off the solar
disk. No CME appeared to be associated with the partial filament
lift off in the southwest solar quadrant. The solar wind speed
on UT day 28-Apr steady, ranging from 360 to 450 km/s and is
currently near 380 km/s. The peak total interplanetary magnetic
field strength (IMF, Bt) was 8 nT and the north-south IMF component
(Bz) range was -6 to +6 nT. Using 27 day recurrence the solar
wind is expected to remain steady for 29-Apr. A small coronal
hole is passing the solar central meridian with centre located
at N20W05 and may mildly increase the solar wind speed during
01-02 May.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 28 Apr: G0
Estimated Indices 28 Apr : A K
Australian Region 1 21010000
Cocos Island 1 12010000
Darwin 3 21111011
Townsville 3 22021001
Learmonth 1 21010000
Alice Springs 1 11010000
Gingin 1 20010000
Canberra 1 21010000
Kennaook Cape Grim 1 1101100-
Hobart 1 10011000
Estimated Antarctic Regional K Indices 28 Apr :
Macquarie Island 0 10001000
Casey 5 33220000
Mawson 5 42110000
Observed Regional daily pc3 Indices 28 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 4 (Quiet)
Hobart 4 (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 28 Apr : A
Fredericksburg 6
Planetary 7
Observed AFr/Ap Indices 27 Apr : A K
Fredericksburg 6
Planetary 6 1211 2221
2B. MAGNETIC FORECAST
Date Ap Conditions
29 Apr 6 G0
30 Apr 9 G0
01 May 15 G0, chance G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
and Antarctic regions on UT day 28-Apr. G0 geomagnetic conditions
are generally expected over 29-Apr to 01-May. A mild increase
in geomagnetic activity may be experienced 01-02 May due to a
coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
28 Apr Normal Fair-normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
29 Apr Normal Normal Fair-normal
30 Apr Normal Normal Fair-normal
01 May Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 28-Apr were
mostly normal, with fair conditions at middle to high latitudes.
HF radio propagation conditions are expected to be mostly normal
over 29-30 Apr. HF conditions at middle to high latitudes are
expected to fair over 01-02 May due to 27 recurrent geomagnetic
activity patterns. Isolated minor fadeouts possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
28 Apr 131
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 30% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Enhanced by 15% 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
Mar 126
Apr 115
May 113
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
29 Apr 125 Near predicted monthly values
30 Apr 125 Near predicted monthly values
01 May 125 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 28-Apr were near predicted monthly values. Spread
F was observed at Hobart during local night hours. Ionospheric
equatorial scintillation was observed during the interval 28/0855-1320UT
at Darwin, Weipa and Niue. MUFs are expected to be near predicted
monthly values over 29-Apr to 01-May. Southern Australian region
HF conditions may become mildly degraded during local night hours
01-02 May. Isolated minor fadeouts possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 27 Apr
Daily Proton Fluence >1 MeV: 9.4E+05
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 4.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B8.9
DSCOVR Satellite Solar Wind Day Averaged Data for 27 Apr
Speed: 402 km/sec Density: 1.8 p/cc Temp: 79000 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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