[Ips-dsgr] ASWFC Daily Report - 26 May 25 issued 2332 UT on 26 May 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Tue May 27 09:32:09 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 26 MAY AND FORECAST FOR 27 MAY - 29 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 26 May: R1
Flares Max Fadeout Freq. Sectors
M2.9 1306UT possible lower European
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 May: 133/87
1B. SOLAR FORECAST
27 May 28 May 29 May
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 135/89 130/84 125/78
COMMENT: Solar activity on UT day 26-May was at the R1 level
due to an M2.9 flare at 26/1306UT and an M1.4 flare at 26/1337UT.
There are currently eight numbered sunspot regions visible on
the solar disk and one unnumbered region. The flares of the UT
day were produced by AR4098 (S04W63, beta) which showed spot
decay on 26-May and is soon to leave the solar disk and, newly
numbered, AR4100 (N07E65, beta) which has recently arrived and
appears stable. AR4099 (S13E55, gamma) showed spot developement
and is currently the largest and most magnetically complex region
visible. All other sunspot regions are either stable or in decay.
An unnumbered region has developed at around S26E17 with beta
magnetic characteristics. Solar activity is expected to be at
R1-R2 levels over 27-29 May. S0 solar radiation conditions were
observed on 26-May and S0 conditions are expected on 27-29 May.
An east directed CME was observed form 26/1424UT in SOHO and
STEREO-A imagery, associated with the M1.4 flare at 26/1337UT.
Analysis is still ongoing but this CME is not considered likely
to be geoeffective. The solar wind speed on UT day 26-May increased
slightly, ranging from 365 to 495 km/s and is currently near
430 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 10 nT and the north-south IMF component (Bz) range
was -9 to +9 nT. Bz was predominantly northward (positive) throughout
the UT day. The solar wind speed is expected to remain at current
levels for most of 27-May with an increase expected from late
on 27-May and over 28-29 May due to a series of equatorial coronal
holes approaching a geoeffective location.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 26 May: Quiet
Estimated Indices 26 May : A K
Australian Region 3 11202111
Cocos Island 5 12212112
Darwin 0 10-00000
Townsville 5 11203112
Learmonth 6 12213112
Alice Springs 4 12202111
Gingin 4 12202112
Canberra 2 01102111
Kennaook Cape Grim 2 01102111
Hobart 2 01102111
Estimated Antarctic Regional K Indices 26 May :
Macquarie Island 0 00000001
Casey 8 33321012
Mawson 33 22322176
Observed Regional daily pc3 Indices 26 May :
Darwin 21 (Quiet to unsettled)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 11 (Quiet)
Hobart 16 (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 26 May : A
Fredericksburg 8
Planetary 8
Observed AFr/Ap Indices 25 May : A K
Fredericksburg 6
Planetary 0 2221 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
27 May 6 Quiet
28 May 24 Active
29 May 14 Unsettled to Active
COMMENT: Disturbed geomagnetic conditions expected during the
forecast period.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 May Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 May Normal Normal Normal
28 May Normal Normal-fair Fair
29 May Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 26-May were
normal to fair. HF radio propagation conditions are expected
to be mostly normal to fair over 27-29 May. Shortwave fadeouts
are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 May 77
Observed Australian Regional MUFs
Cocos Island Region:
Depressed by 15% during local day.
Depressed by 30% during local night.
Niue Island Region:
No data available during local day.
No data available during local night.
Northern Australian Region:
Depressed by 15% during local day.
Depressed by 30% during local night.
Depressed by 20% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
Depressed by 20% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Apr 123
May 113
Jun 111
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 May 75 15 to 20% below predicted monthly values
28 May 75 15 to 20% below predicted monthly values
29 May 80 15 to 20% below predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 52 was issued on
25 May and is current for 25-27 May. ASWFC HF Communications
Warning 53 was issued on 25 May and is current for 26-27 May.
Maximum usable frequencies (MUFs) in the Australian region on
UT day 26-May were near predicted monthly values to 30% depressed.
Spread F was observed at Hobart, Canberra, Townsville and Brisbane
during local night hours. MUFs are expected to be 15-20% depressed
over 27-29 May. Shortwave fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 May
Daily Proton Fluence >1 MeV: 2.7E+05
Daily Proton Fluence >10 MeV: 1.6E+04
Daily Electron Fluence >2 MeV: 2.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 4%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.1
DSCOVR Satellite Solar Wind Day Averaged Data for 25 May
Speed: 381 km/sec Density: 4.0 p/cc Temp: 79500 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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