[Ips-dsgr] ASWFC Daily Report - 04 April 26 issued 2330 UT on 04 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Apr 5 09:30:44 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/04 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 04 APRIL AND FORECAST FOR 05 APRIL - 07 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 04 Apr: R2
Flares Max Fadeout Freq. Sectors
M7.5 0117UT probable lower West Pacific
M1.7 0759UT possible lower Mid East/Indian
M1.3 1211UT possible lower European
M1.0 2304UT possible lower West Pacific
Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Apr: 128/81
1B. SOLAR FORECAST
05 Apr 06 Apr 07 Apr
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 125/78 125/78 120/72
COMMENT: Solar flare activity reached the R2 level on UT day
04-Apr, with an M7.5 flare from Active Region (AR) 4409 (N05W12,
beta-gamma) peaking at 04/0117UT. This region was also responsible
for an M1.7 flare at 04/0701UT, an M1.2 flare at 04/1158UT, and
an M1.0 flare peaking at 04/2304UT. AR 4409 is the most magnetically
complex of the seven regions on the visible solar disk, and has
shown minor decay over the last 24 hours. All other regions are
either stable or in decay. Solar flare activity is forecast to
be at R1-R2 levels over 05-07 Apr, driven by the current flare
activity of AR 4409. Solar proton conditions were at the S0 level,
with the solar proton flux declining from a maximum value of
6.57 pfu over the UT day. S0 solar proton conditions are forecast
over 05-07 Apr, with the solar proton flux expected to continue
to decline toward background values. No geoeffective coronal
mass ejections (CMEs) have been observed over the past UT day
in available coronagraph imagery. The solar wind was very strong
at the start of UT day 04-Apr due to the ongoing effects of both
a past CME impact and a coronal hole high-speed wind stream.
The wind speed started the UT day at 700 km/s and slowly declined
over the day, and is currently ranging between 560-590 km/s.
The interplanetary magnetic field strength (IMF, Bt) peaked at
5 nT early in UT day 04-Apr, with the north-south component (Bz)
ranging between -4 and +4 nT. The solar wind speed is expected
to continue to decline over 05-07 Apr as the effects of the CME
impact wane, and the coronal hole high-speed wind stream moves
beyond a geoeffective position.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 04 Apr: G0
Estimated Indices 04 Apr : A K
Australian Region 7 22221132
Cocos Island 5 22120131
Darwin 8 32221232
Townsville 8 23221132
Learmonth - --------
Alice Springs 6 22220131
Gingin 8 32220141
Canberra 5 22220122
Kennaook Cape Grim 8 22231132
Hobart 10 32331132
Estimated Antarctic Regional K Indices 04 Apr :
Macquarie Island 18 34452132
Casey 14 43421133
Mawson 36 64432265
Observed Regional daily pc3 Indices 04 Apr :
Darwin 2 (Quiet)
Townsville 0 (Quiet)
Learmonth NA
Alice Springs 4 (Quiet)
Gingin 92 (Minor storm)
Canberra 38 (Quiet to unsettled)
Hobart 144 (Severe storm)
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 04 Apr : A
Fredericksburg 19
Planetary 25
Observed AFr/Ap Indices 03 Apr : A K
Fredericksburg 25
Planetary 49 4454 4766
2B. MAGNETIC FORECAST
Date Ap Conditions
05 Apr 10 G0
06 Apr 8 G0
07 Apr 6 G0
COMMENT: Geomagnetic conditions were at the G0 level across the
Australian region on UT day 04-Apr. G1-G2 geomagnetic conditions
were reported in the Antarctic region, with G1 conditions observed
at the planetary level early in the UT day. G0 geomagnetic conditions
are expected across 05-07 Apr as the effects of a past CME impact
and a coronal hole high speed wind stream continue to subside.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
04 Apr Fair-poor Poor Poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
05 Apr Fair-normal Fair Fair
06 Apr Normal-fair Normal-fair Fair-normal
07 Apr Normal Normal Fair-normal
COMMENT: Global ionospheric conditions were poor at the start
of UT day 04-Apr due to ongoing geomagnetic activity, with degradations
seen across several regions. Conditions improved to fair by the
end of the UT day, particularly in low latitude regions. MUFs
in the European region were depressed by 20-30% during the UT
day. Conditions are expected to improve to fair-normal conditions
on 05-Apr as geomagnetic conditions improve. Further improvements
towards normal ionospheric conditions are expected over 06-07
Apr. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
04 Apr 63
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 40% during local day.
Enhanced by 50% during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 30% during local day.
Enhanced by 25% during local night.
Northern Australian Region:
Depressed by 20% during local day.
Depressed by 15% during local night.
Southern Australian Region:
Depressed by 35% during local day.
Depressed by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Mar 92
Apr 83
May 81
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
05 Apr 65 Depressed 10 to 15%/near predicted monthly values
06 Apr 80 Near predicted monthly values
07 Apr 85 Near predicted monthly values
COMMENT: ASWFC HF Communications Warning 33 was issued on 3 April
and is current for 4-5 Apr. ASWFC SWF HF Communications Warning
34 was issued on 3 April and is current for 4-5 Apr. Maximum
Usable Frequencies (MUFs) were depressed by 20-35% in the Australian
region during 04-Apr, due to ongoing geomagnetic activity. Enhancements
were observed at Niue Island and the Cocos Islands, whilst MUFs
in the Antarctic region were near predicted monthly values. Spread
F was observed in Perth and Townsville, and strong sporadic E
was observed in Canberra, Hobart, Perth, Townsville, and Norfolk
Island. MUFs are expected to be 10-15% depressed on UT day 05-Apr,
recovering to near predicted monthly values by 06-07 Apr as the
effects of current geomagnetic activity subside. Shortwave fadeouts
are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 03 Apr
Daily Proton Fluence >1 MeV: 8.6E+07
Daily Proton Fluence >10 MeV: 3.8E+05
Daily Electron Fluence >2 MeV: 9.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:10%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B8.8
DSCOVR Satellite Solar Wind Day Averaged Data for 03 Apr
Speed: 662 km/sec Density: 1.0 p/cc Temp: 197000 K Bz: -2 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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