[Ips-dsgr] ASWFC Daily Report - 26 April 26 issued 2330 UT on 26 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon Apr 27 09:30:47 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 APRIL AND FORECAST FOR 27 APRIL - 29 APRIL
STATUS INDICATORS SOL:** RED ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 Apr: R2
Flares Max Fadeout Freq. Sectors
M1.3 0023UT possible lower West Pacific
M1.4 1403UT possible lower South American/
Atlantic
M1.7 1924UT possible lower East Pacific/
North American
M2.2 2004UT possible lower East Pacific/
North American
M6.0 2257UT probable lower East Pacific/
North American
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Apr: 156/110
1B. SOLAR FORECAST
27 Apr 28 Apr 29 Apr
Activity R2, chance of R3 R2, chance of R3 R2, chance of R3
Fadeouts Probable Probable Probable
10.7cm/SSN 155/109 150/105 150/105
COMMENT: Solar flare activity on UT day 26-Apr was at the R2
level due to an M6.0 flare at 26/2257UT produced by Active Region
(AR) 4420 (N16W13, beta-gamma-delta). Four R1 level flares were
also observed over the UT day, all of which were produced by
regions 4420 and 4425 (N05E52, beta-delta). There are currently
six numbered sunspot regions visible on the solar disk. AR 4420
is the largest and most magnetically complex region on the disk.
This region has shown spot development in its leader spots, whilst
some decay was observed in its trailer spots. Region 4425 has
exhibited spot development in its trailer spots over the UT day.
All other sunspot regions are either stable or in decay. Solar
flare activity is expected to be at the R2 level over 27-29 Apr,
with a chance of R3 due to the complexity and observed flare
activity of regions 4420 and 4425. S0 solar proton conditions
were observed on UT day 26-Apr. S0 solar proton conditions are
expected over 27-29 Apr. No Earth-directed coronal mass ejections
(CMEs) have been observed, however imagery is not yet available
to confirm if there is a CME associated with the M6.0 flare from
AR 4420. The solar wind speed on UT day 26-Apr mildly increased,
ranging from 410 to 490 km/s and is currently near 460 km/s.
The peak total interplanetary magnetic field strength (IMF, Bt)
was 14 nT and the north-south IMF component (Bz) range was -14
to +12 nT. The solar wind speed is expected to decrease over
27-28 Apr, then mildly increase on 29-Apr due to a small southern
hemisphere coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 Apr: G0
Estimated Indices 26 Apr : A K
Australian Region 7 23230022
Cocos Island 5 23220021
Darwin 10 33231132
Townsville 10 24331122
Learmonth 7 23230122
Alice Springs 7 23230022
Gingin 5 22220022
Canberra 8 23330022
Kennaook Cape Grim 9 23340012
Hobart 9 23340012
Estimated Antarctic Regional K Indices 26 Apr :
Macquarie Island 11 23350012
Casey 12 44321122
Mawson 27 45442116
Observed Regional daily pc3 Indices 26 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 37 (Quiet to unsettled)
Canberra 39 (Quiet to unsettled)
Hobart 37 (Quiet to unsettled)
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 26 Apr : A
Fredericksburg 12
Planetary 16
Observed AFr/Ap Indices 25 Apr : A K
Fredericksburg 7
Planetary 9 3111 1233
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Apr 8 G0
28 Apr 6 G0
29 Apr 12 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
and planetary regions on UT day 26-Apr. Mostly G0-G1 geomagnetic
conditions were observed in the Antarctic region, with an isolated
period of G2 observed at Mawson. G0 geomagnetic conditions are
expected over 27-29 Apr, with a chance of G1 on 29-Apr due to
coronal hole high speed wind stream effects from a small southern
hemisphere coronal hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Apr Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Apr Normal Normal Normal-fair
28 Apr Normal Normal Normal
29 Apr Normal Normal Normal-fair
COMMENT: Global ionospheric conditions were mostly normal on
UT day 26-Apr. Mostly normal HF conditions are expected over
27-29 Apr. Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Apr 82
Observed Australian Regional MUFs
Cocos Island Region:
No data available during local day.
No data available during local night.
Niue Island Region:
Enhanced by 30% during local day.
Near predicted monthly values 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 92
Apr 83
May 81
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 Apr 80 Near predicted monthly values
28 Apr 80 Near predicted monthly values
29 Apr 80 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 26-Apr. Spread-F was observed at Hobart and Canberra.
MUFs are expected to be near predicted monthly values over 27-29
Apr. Shortwave fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Apr
Daily Proton Fluence >1 MeV: 5.7E+05
Daily Proton Fluence >10 MeV: 2.6E+04
Daily Electron Fluence >2 MeV: 1.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B9.4
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Apr
Speed: 410 km/sec Density: 3.5 p/cc Temp: 83800 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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