[Ips-dsgr] ASWFC Daily Report - 01 April 26 issued 2330 UT on 01 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Apr 2 10:30:43 AEDT 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/01 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 01 APRIL AND FORECAST FOR 02 APRIL - 04 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 01 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 01 Apr: 142/96
1B. SOLAR FORECAST
02 Apr 03 Apr 04 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 145/99 140/94 135/89
COMMENT: Solar flare activity on UT day 01-Apr was R0. Solar
region AR4409 (N03E30, beta-gamma) consists of numerous small
spots and has shown rapid growth. This region produced isolated
C flare activity, the largest a C8.1 at 01/1958UT. Solar region
AR4404 (N17W04, beta) is showing slight growth with an increase
in small surrounding spots. Solar region AR4405 (S26E08, beta)
that produced the recent isolated R3 flare continues to slowly
decay with an increase in overall spot separation and extent.
There are currently nine Active Regions on the solar disk. All
other sunspot regions are either stable or in decay. Solar activity
is expected to be R0-R1 over 02-04-Apr. Two filament eruptions
were observed in the southwest solar quadrant, the first at 01/0309UT
where two filament segments located at S40W40 and S25W70 lifted
off and the second a 20 degree long filament located at S20W50
erupting at 01/1740UT.No Earth directed CMEs have been observed.
Two west directed CMEs were observed in association with the
filament eruptions. The first west directed CME was analysed
to have a very slow speed (<200km/s) with limited expansion and
is not considered significant enough to model. The second CME
was also quite slow and was modelled as an Earth miss. S0 solar
radiation storm conditions were observed on UT day 01-Apr. S0
solar radiation storm conditions are expected over 02-04-Apr.
An isolated coronal hole is visible just west of the solar central
meridian. The solar wind speed on UT day 01-Apr was steady at
approximately 360-390 km/s before a solar wind shock was observed
at 01/1130UT. This CME shock is probably from the R3 flare from
30-Mar. The solar wind parameters were only mildly to moderately
enhanced by this glancing blow CME arrival, with the solar wind
speed increasing to approximately 500km/sec at the time of the
shock then declining. No significant period of southward IMF
Bz conditions were observed post shock arrival. This CME arrived
later and weaker than forecast. The solar wind ranged from 360
to 500 km/s and is currently at 390 km/s. The peak total interplanetary
field strength (IMF, Bt) was 16 nT and the north-south IMF component
range (Bz) was +9 to -10nT. The solar wind speed is expected
to slowly decline before increasing to approximately 600km/s
over 03-04 Apr due to the high speed wind stream from the coronal
hole now just west of the solar central meridian.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 01 Apr: G0
Estimated Indices 01 Apr : A K
Australian Region 6 21113212
Cocos Island 5 11123211
Darwin 6 22113212
Townsville 9 22124222
Learmonth - --------
Alice Springs 6 21113212
Gingin 5 21113211
Canberra 5 21013212
Kennaook Cape Grim 6 21113212
Hobart 6 22113211
Estimated Antarctic Regional K Indices 01 Apr :
Macquarie Island 5 11023211
Casey 13 34423212
Mawson 17 54323322
Observed Regional daily pc3 Indices 01 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth NA
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 6 (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 01 Apr : A
Fredericksburg 11
Planetary 14
Observed AFr/Ap Indices 31 Mar : A K
Fredericksburg 8
Planetary 7 2322 2211
2B. MAGNETIC FORECAST
Date Ap Conditions
02 Apr 12 G0
03 Apr 22 G1
04 Apr 17 G0-G1
COMMENT: ASWFC Geomagnetic Warning 23 was issued on 1 April and
is current for 3-4 Apr. G0 geomagnetic conditions were observed
in the Australian region on UT day 01-Apr. G0-G1 geomagnetic
conditions were observed in the Antarctic region. A weak (9nT)
sudden impulse was observed at 01/1203UT in association with
a weak glancing blow CME arrival. No significant geomagnetic
activity followed the sudden impulse. Geomagnetic conditions
are now expected to be G0 for most of 02-Apr, increasing to G1
on 03-Apr due to to the anticipated onset of a coronal hole high
speed wind stream. G0-G1 conditions are expected for 04-Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
01 Apr Normal Normal Fair-normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
02 Apr Normal Normal Normal-fair
03 Apr Normal Normal-fair Fair
04 Apr Normal Fair Fair
COMMENT: HF radio propagation conditions on UT day 01-Apr were
fair to normal. An anticipated CME arrival has eventuated but
with minimal effects. HF conditions are expected to be fair to
normal. Fair HF conditions are expected at middle to high latitudes
on 03-04 Apr due to anticipated geomagnetic activity from a coronal
hole wind stream. Isolated minor fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
01 Apr 116
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 85% during local night.
Niue Island Region:
Enhanced by 30% during local day.
Near predicted monthly values during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 35% during local night.
Enhanced by 20% after local dawn.
Southern Australian Region:
Mostly near predicted monthly values.
Enhanced by 25% after local dawn.
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
02 Apr 100 Near predicted monthly values to 15% enhanced
03 Apr 90 Near predicted monthly values
04 Apr 70 Depressed 10 to 15%/near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 31 was issued
on 1 April and is current for 4 Apr only. Maximum usable frequencies
(MUFs) in the Australian region on UT day 01-Apr were near predicted
values to 35% enhanced. Strong local night enhancements were
observed at Darwin. A weaker than expected CME has arrived later
than expected inducing little geomagnetic activity. MUFs are
now expected to be near predicted monthly values to 15% enhanced for
02-Apr. A coronal hole wind stream is expected to increase geomagnetic
activity on 03-Apr. Southern Australian MUFs may become mildly
(15%) depressed on 04-Apr. Isolated minor short wave fadeouts
are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 31 Mar
Daily Proton Fluence >1 MeV: 2.8E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 4.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 6%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.3
DSCOVR Satellite Solar Wind Day Averaged Data for 31 Mar
Speed: 420 km/sec Density: 2.3 p/cc Temp: 66000 K Bz: 0 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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