[Ips-dsgr] ASWFC Daily Report - 23 May 26 issued 2330 UT on 23 May 2026 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun May 24 09:30:48 AEST 2026
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 MAY 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 23 MAY AND FORECAST FOR 24 MAY - 26 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 23 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 23 May: 137/91
1B. SOLAR FORECAST
24 May 25 May 26 May
Activity R0, chance of R1 R0, chance of R1 R0, chance of R1
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 145/99 145/99
COMMENT: Solar flare activity on UT day 23-May was at the R0
level, with no significant flaring activity. There are currently
five numbered sunspot regions on the solar disk. Active Region
(AR) 4441 (N08W65, beta) is the largest region on the disk and
has shown consolidation of intermediate spots and mild decay
in its trailer spots. AR4444 (S19E42, beta gamma) has showed
development in its leader spots over the UT day. All other sunspot
regions are either stable or in decay. Solar flare activity is
expected to be at the R0 level over 24-26 May, with a chance
of R1. S0 solar radiation conditions were observed on UT day
23-May. S0 solar radiation conditions are expected over 24-26
May. No Earth-directed coronal mass ejections (CMEs) were observed
on 23-May. Two northwest-directed CME's was observed in LASCO
C2 coronagraph imagery at 23/0648UT and 23/1612UT, both are attributed
to far side eruptions. The solar wind speed decreased over 23-May.
The speed ranged from 320 to 370 km/s and is currently near 330
km/s. The peak total interplanetary magnetic field strength (IMF,
Bt) was 5 nT and the north-south IMF component (Bz) range was
-3 to +4 nT. The solar wind speed is expected to remain at background
levels over 24-25 May and may increase 26 May as a southern hemisphere
coronal hole moves into a geoeffective position.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 23 May: G0
Estimated Indices 23 May : A K
Australian Region 0 00100000
Cocos Island 0 00100000
Darwin 1 11100001
Townsville 2 11200001
Learmonth 1 11100000
Alice Springs 0 00100000
Gingin 0 00100000
Canberra 0 00100000
Kennaook Cape Grim 0 01000000
Hobart 0 00100000
Estimated Antarctic Regional K Indices 23 May :
Macquarie Island 0 00000000
Casey 3 23200000
Mawson 3 31201100
Observed Regional daily pc3 Indices 23 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 0 (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 23 May : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 22 May : A K
Fredericksburg 5
Planetary 6 1222 1113
2B. MAGNETIC FORECAST
Date Ap Conditions
24 May 4 G0
25 May 8 G0
26 May 14 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
and Antarctic regions on UT day 23-May. G0 geomagnetic conditions
are expected over 24-25 May with a chance of G1 conditions on
26-May due to a coronal hole moving into a geoeffective position.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
23 May Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
24 May Normal Normal Normal
25 May Normal Normal Normal-fair
26 May Normal Normal Normal-fair
COMMENT: Global ionospheric conditions were normal over UT day
23-May, with mild degradations mostly observed in the northern
hemisphere in the first third of the UT day. Mostly normal HF
propagation conditions are expected over 24-26 May.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
23 May 64
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 during local day.
Enhanced by 35% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Apr 74
May 71
Jun 68
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
24 May 60 Near predicted monthly values
25 May 60 Near predicted monthly values
26 May 55 Near predicted monthly values
COMMENT: Maximum Usable Frequencies (MUFs) on UT day were depressed
by up to 20% during local night hours in the southern Australian
region and enhanced to 35% during the local night in northern
Australian region. Spread-F was observed at Hobart during local
night hours. MUFs are expected to be near predicted monthly values
over 24-26 May.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 22 May
Daily Proton Fluence >1 MeV: 8.0E+05
Daily Proton Fluence >10 MeV: 1.9E+04
Daily Electron Fluence >2 MeV: 1.70E+08 (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:14%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B7.3
DSCOVR Satellite Solar Wind Day Averaged Data for 22 May
Speed: 373 km/sec Density: 1.7 p/cc Temp: 49100 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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