[Ips-dsgr] ASWFC Daily Report - 25 April 26 issued 2331 UT on 25 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun Apr 26 09:31:09 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 APRIL AND FORECAST FOR 26 APRIL - 28 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 Apr: R1
Flares Max Fadeout Freq. Sectors
M1.3 0759UT possible lower Mid East/Indian
M1.1 1430UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Apr: 148/na
1B. SOLAR FORECAST
26 Apr 27 Apr 28 Apr
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 148/102 145/99 145/99
COMMENT: Solar flare activity on UT day 25-Apr was at the R1
level due to two M-class flares, the largest of which was an
M1.3 at 25/0759UT produced by active region (AR) 4423 (S07E22,
beta-delta). There are currently seven numbered sunspot regions
visible on the solar disk. AR 4420 (N16E02, beta-gamma-delta)
is the largest and most magnetically complex region on the disk.
This region has shown spot development in its intermediate spots
including the development of a delta spot, whilst its trailer
spots have exhibited some decay over the UT day. Regions 4424
(N17E33, beta) and 4425 (N05E65, beta) have both exhibited spot
growth in their trailer spots. All other sunspot regions are
either stable or in decay. Solar flare activity is expected to
be at R1-R2 levels over 26-28 Apr due to the magnetic complexity
of regions 4420, 4423 and possible beyond-the-limb flares from
region 4419. S0 solar proton conditions were observed on UT day
25-Apr. S0 solar proton conditions are expected over 26-28 Apr,
with a chance of S1. No Earth-directed coronal mass ejections
(CMEs) have been observed. The solar wind speed on UT day 25-Apr
mildly increased, ranging from 360 to 445 km/s and is currently
near 425 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 12 nT and the north-south IMF component (Bz) range
was -10 to +8 nT. A period of sustained southward IMF conditions
was observed over the interval 25/2002-2210UT. The solar wind
speed is expected to increase on 26-Apr due to the arrival of
a CME first observed on 23-Apr. The solar wind is expected to
decrease over 27-28 Apr.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 Apr: G0
Estimated Indices 25 Apr : A K
Australian Region 5 22110132
Cocos Island 4 21110131
Darwin 6 32110132
Townsville 5 2--11222
Learmonth 6 32110132
Alice Springs 5 21110132
Gingin 6 32200132
Canberra 3 22000122
Kennaook Cape Grim 4 22110122
Hobart 4 22100122
Estimated Antarctic Regional K Indices 25 Apr :
Macquarie Island 2 21000021
Casey 12 34420132
Mawson 24 43311165
Observed Regional daily pc3 Indices 25 Apr :
Darwin 0 (Quiet)
Townsville 27 (Quiet to unsettled)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 8 (Quiet)
Canberra 2 (Quiet)
Hobart 2 (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 25 Apr : A
Fredericksburg
Planetary
Observed AFr/Ap Indices 24 Apr : A K
Fredericksburg 8 2121 3123
Planetary 9 3121 2133
2B. MAGNETIC FORECAST
Date Ap Conditions
26 Apr 26 G1-G2
27 Apr 14 G0, chance of G1
28 Apr 10 G0
COMMENT: ASWFC Geomagnetic Warning 30 was issued on 25 April
and is current for 26 Apr only. G0 geomagnetic conditions were
observed in the Australian and planetary regions on UT day 25-Apr.
Mostly G0-G1 geomagnetic conditions were observed in the Antarctic
region, with an isolated period of G2 observed at Mawson. G1-G2
geomagnetic conditions are forecast for 26-Apr due to the combined
effects of the coronal hole high speed wind stream as well as
the arrival of a CME first observed on 23-Apr. G0 geomagnetic
conditions are expected over 27-28 Apr, with a chance of G1 on
27-Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 Apr Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 Apr Fair Fair Fair-poor
27 Apr Normal Normal Normal-fair
28 Apr Normal Normal Normal-fair
COMMENT: Global ionospheric conditions were mostly normal on
UT day 25-Apr. Ionospheric conditions are expected to trend toward
fair conditions over 26-27 Apr due to forecast geomagnetic activity.
Mostly normal HF conditions are expected on 28-Apr. Shortwave
fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 Apr 77
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Near predicted monthly values.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% 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
26 Apr 60 Depressed 15%/near predicted monthly values
27 Apr 60 Depressed 15%/near predicted monthly values
28 Apr 75 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 42 was issued on
25 April and is current for 26-28 Apr. Maximum Usable Frequencies
(MUFs) in the Australian region were near predicted monthly values
on UT day 25-Apr. Spread-F was observed at Hobart. MUFs are expected
to be near predicted monthly values to 15% depressed over 26-27
Apr due to forecast geomagnetic activity, then recover to near
predicted monthly values on 28-Apr. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 Apr
Daily Proton Fluence >1 MeV: 6.1E+05
Daily Proton Fluence >10 MeV: 2.1E+04
Daily Electron Fluence >2 MeV: 2.50E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:17%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.4
DSCOVR Satellite Solar Wind Day Averaged Data for 24 Apr
Speed: 389 km/sec Density: 3.1 p/cc Temp: 38800 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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