[Ips-dsgr] ASWFC Daily Report - 28 April 26 issued 2330 UT on 28 Apr 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed Apr 29 09:30:23 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/28 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 28 APRIL AND FORECAST FOR 29 APRIL - 01 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 28 Apr: R1
Flares Max Fadeout Freq. Sectors
M1.0 1223UT possible lower European
M1.5 1353UT possible lower European
M1.1 1407UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 28 Apr: 149/104
1B. SOLAR FORECAST
29 Apr 30 Apr 01 May
Activity R1, chance of R2 R1, chance of R2 R1, chance of R2
Fadeouts Possible Possible Possible
10.7cm/SSN 148/102 148/102 145/99
COMMENT: Solar flare activity reached the R1 level on UT day
28-Apr, with an M1.0 flare at 28/1217UT, and a M1.5 flare at
28/1349UT, both originating from Active Region (AR) 4420 (N16W44,
beta-delta). This region is one of seven sunspot regions on the
visible disk, and has shown some minor decay over the past UT
day. Previously flare active region AR 4425 (N05E24, beta-gamma)
has shown some growth and spot separation in the last 24 hours.
AR 4428 (S23E14, beta) has also shown some growth over the same
period. All other regions are either stable or in decay. Solar
flare activity is forecast to be at the R1 level, with a chance
of R2 over 29-Apr to 01-May, given the presence of large, magnetically
complex sunspot regions on the Earth‑facing solar disk. S0 solar
proton conditions were observed throughout UT day 28-Apr, with
solar proton flux persisting at background levels. S0 solar proton
conditions are forecast for 29-Apr to 01-May. No coronal mass
ejections (CMEs) were observed over the past UT day. The solar
wind speed declined towards background levels throughout UT day
28-Apr, beginning the UT day at approximately 430 km/s, and declining
to between 350 and 370 km/s. The interplanetary magnetic field
strength (IMF, Bt) peaked at 5 nT during the UT day, and the
north-south component (Bz) ranged between -2 and +4 nT over the
UT day. The solar wind speed is expected to increase over 29-30
Apr due to high speed wind streams from a small equatorial coronal
hole. These conditions will then begin to ease on 01-May.
-----------------------------------------------------------
2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 28 Apr: G0
Estimated Indices 28 Apr : A K
Australian Region 0 00100010
Cocos Island 1 11000010
Darwin 2 10100021
Townsville 1 11100011
Learmonth 1 10100010
Alice Springs 0 00100010
Gingin 0 00100010
Canberra 0 00100010
Kennaook Cape Grim 0 00100010
Hobart 0 00100010
Estimated Antarctic Regional K Indices 28 Apr :
Macquarie Island 0 00000000
Casey 2 22200000
Mawson 1 11100000
Observed Regional daily pc3 Indices 28 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 4 (Quiet)
Canberra 11 (Quiet)
Hobart 11 (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 28 Apr : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 27 Apr : A K
Fredericksburg 6
Planetary 7 3211 22-1
2B. MAGNETIC FORECAST
Date Ap Conditions
29 Apr 12 G0, chance of G1
30 Apr 14 G0, chance of G1
01 May 10 G0
COMMENT: G0 geomagnetic conditions were recorded in the Australian
region throughout UT day 28-Apr, with G0 conditions also recorded
in the Antarctic region, and at the planetary level. G0 geomagnetic
conditions, with a chance of G1 are forecast over 29-30 Apr due
to anticipated high speed wind stream effects from an equatorial
coronal hole, declining to G0 on 01-May as these effects begin
to subside.
-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
28 Apr Normal Normal-fair Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
29 Apr Normal Normal Normal
30 Apr Normal Normal-fair Normal-fair
01 May Normal Normal-fair Normal-fair
COMMENT: Global ionospheric conditions were mostly normal across
UT day 28-Apr, with some degradations seen in the South American
and South African regions. Mostly normal ionospheric conditions
are forecast for 29-Apr, with normal to fair conditions forecast
on 30-Apr and 01-May due to coronal hole high speed wind stream
effects. Shortwave fadeouts are possible.
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
28 Apr 75
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 during local day.
Depressed by 20% 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
29 Apr 80 Near predicted monthly values
30 Apr 70 Near predicted monthly values
01 May 70 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 43 was issued on
27 April and is current for 27-29 Apr. Maximum Usable Frequencies
(MUFs) in the Australian and Antarctic regions were near predicted
monthly values across UT day 28-Apr, with depressions of around
20% observed at Niue Island during local night hours. Spread-F
was observed at Hobart, and sporadic E was observed in Canberra.
Ionospheric scintillation was observed at Darwin between 28/1338-1510UT.
MUFs are expected to remain near predicted values on 29-Apr,
with some small depressions possible on 30-Apr and 01-May due
to forecast geomagnetic activity. Shortwave fadeouts are possible.
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 27 Apr
Daily Proton Fluence >1 MeV: 2.0E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 1.40E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.4
DSCOVR Satellite Solar Wind Day Averaged Data for 27 Apr
Speed: 447 km/sec Density: 3.8 p/cc Temp: 85700 K Bz: 1 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------
Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
More information about the ips-dsgr
mailing list