[Ips-dsgr] ASWFC Daily Report - 24 April 25 issued 2331 UT on 24 Apr 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Fri Apr 25 09:31:10 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 APRIL 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 24 APRIL AND FORECAST FOR 25 APRIL - 27 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 24 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Apr: 170/124
1B. SOLAR FORECAST
25 Apr 26 Apr 27 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 170/124 170/124 170/124
COMMENT: Solar activity on UT day 24-Apr was R0. Solar region
AR4064 (N11W28, beta-gamma) leader spots showed growth. Solar
region AR4070 (S13E18, beta) showed spot redistribution with
some decay. Solar region AR4064 and AR4070 produced low C class
flares. Small solar region AR4073 (N12E43, beta) is currently
rapidly growing. Other regions are quite small and stable. There
are currently eleven numbered sunspot regions on the solar disk.
A 15 degree long solar filament to the southeast of solar region
AR4064, with centre at N08W12 was active and may have partially
lifted off from 24/0522UT. Two small filaments surrounding solar
region AR4065 (S30W23, beta) lifted off from 24/1200UT. A large
eruptive prominence on the north west solar limb erupted 24/0409-0623UT.
Solar activity is expected to be R0-R1 over 25-27 Apr. S0 solar
radiation storm conditions were observed on UT day 24-Apr. S0
solar radiation storm conditions are expected over 25-27 Apr.
No Earth directed CMEs have been observed. No CMEs appeared to
be associated with the smaller on disk filament eruptions. The
prominence eruption on the northwest solar limb was associated
with a large CME which due to its western limb location has been
modelled as an Earth miss. During this event a secondary narrow
westward CME was observed from 24/0824UT which could not be correlated
to on disk activity. A CME observed on 22-Apr, modelled with
a considerable southward component, grazed the underside of the
Earth's magnetosphere at 24/0613UT, with a small increase in
the IMF total field from 9 nT to 15 nT. The CME signature in
other solar wind parameters was indistinct with a brief increase
in solar wind speed to 610km/s at the time of arrival. The north-south
component of the IMF (Bz) was very mildly southward post shock
arrival. The solar wind speed ranged from 440 km/s to 610 km/s
and is currently near 485 km/s. The peak total interplanetary
field strength (IMF, Bt) was 15 nT and the north-south IMF component
range (Bz) was +8 to -9 nT. The solar wind speed is expected
to be elevated with a declining trend over 25-Apr, due to a large
coronal hole in the southern solar hemisphere. Due to the shape
of this coronal hole the solar wind may decrease then moderately
increase again on 27-28 Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 24 Apr: G0
Estimated Indices 24 Apr : A K
Australian Region 8 22333111
Cocos Island 7 12332111
Darwin 8 22333111
Townsville 9 22333112
Learmonth 10 22343111
Alice Springs 8 22333111
Gingin 10 22343121
Canberra 8 12333111
Kennaook Cape Grim 8 12333111
Hobart 9 12433111
Estimated Antarctic Regional K Indices 24 Apr :
Macquarie Island 17 11545111
Casey 19 35533112
Mawson 20 33433154
Observed Regional daily pc3 Indices 24 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 6 (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 24 Apr : A
Fredericksburg 10
Planetary 14
Observed AFr/Ap Indices 23 Apr : A K
Fredericksburg 9
Planetary 7 2323 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
25 Apr 12 G0
26 Apr 10 G0
27 Apr 15 G0
COMMENT: G0 Geomagnetic conditions were observed in the Australian
region on UT day 24-Apr. G1 periods were observed in the Antarctic
region. G0 conditions are generally expected for 25-27 Apr, There
is a slight chance of G1 conditions on 27-28 Apr due to the influence
of a coronal hole wind stream.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
24 Apr Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
25 Apr Normal Normal Normal-fair
26 Apr Normal Normal Normal-fair
27 Apr Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 24-Apr were
fair to normal with fair conditions at middle to high latitudes.
HF radio propagation conditions are expected to be mostly normal
over 25-27 Apr with fair conditions at times for middle to high
latitudes.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
24 Apr 124
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 30% 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
25 Apr 115 Near predicted monthly values
26 Apr 115 Near predicted monthly values
27 Apr 115 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 24-Apr were near predicted monthly values. Spread
F was observed at Hobart during local night hours. MUFs are expected
to be near predicted values over 25-27 Apr.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 23 Apr
Daily Proton Fluence >1 MeV: 2.6E+06
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 2.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 23 Apr
Speed: 493 km/sec Density: 1.9 p/cc Temp: 125000 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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