[Ips-dsgr] ASWFC Daily Report - 25 May 25 issued 2331 UT on 25 May 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Mon May 26 09:31:04 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 25 MAY AND FORECAST FOR 26 MAY - 28 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 25 May: R3
Flares Max Fadeout Freq. Sectors
X1.1 0152UT probable all West Pacific
M1.7 0635UT possible lower Mid East/Indian
M3.4 1018UT possible lower European
M8.9 1630UT probable lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 May: 133/87
1B. SOLAR FORECAST
26 May 27 May 28 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 25-May was at the R3 level
due to an X1.1 flare at 25/0152UT produced by AR4098 (S04W48,
beta). This region also produced an M8.9 (R2) flare at 25/1630UT
and two additional flares at the R1 level. There are currently
seven numbered sunspot regions visible on the solar disk and
one unnumbered region. AR4098 is the most flare active region
on the disk and has exhibited spot growth over the UT day. The
region appears to have lost its delta spot and will remain on
the visible disk until 28-May. AR4099 (S13E70, beta) has shown
spot growth. An unnumbered region recently rotated over the eastern
limb near N08E80 (beta). This region is likely the return of
previous region AR4079 and has shown some spot growth. All other
sunspot regions are either stable or in decay. Solar activity
is expected to be at R1-R2 levels over 26-28 May. No Earth-directed
CMEs have been observed. A narrow west-directed CME was observed,
visible in LASCO C2 coronagraph imagery from 25/0236UT. This
CME is likely associated with the aforementioned X1.1 flare from
AR4098. This CME is not considered geoeffective. The solar wind
speed on UT day 25-May declined to background levels, ranging
from 330 to 460 km/s and is currently near 375 km/s. The peak
total interplanetary magnetic field strength (IMF, Bt) was 11
nT and the north-south IMF component (Bz) range was -6 to +8
nT. A small equatorial coronal hole is currently crossing the
central meridian and may influence the solar wind speed on 28-May.
The solar wind speed is expected to remain near background levels
over 26-27 May, then increase on 28-May due to coronal hole high
speed wind stream effects.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 May: G0
Estimated Indices 25 May : A K
Australian Region 3 22211001
Cocos Island 2 11211000
Darwin 4 22211111
Townsville 4 22211111
Learmonth 6 32311101
Alice Springs 3 12211001
Gingin 3 22211001
Canberra 2 12201000
Kennaook Cape Grim 3 12211001
Hobart 3 12211001
Estimated Antarctic Regional K Indices 25 May :
Macquarie Island 1 11011000
Casey 6 23311011
Mawson 11 34322222
Observed Regional daily pc3 Indices 25 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 21 (Quiet to unsettled)
Canberra 25 (Quiet to unsettled)
Hobart 26 (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 25 May : A
Fredericksburg 7
Planetary 8
Observed AFr/Ap Indices 24 May : A K
Fredericksburg 6
Planetary 5
2B. MAGNETIC FORECAST
Date Ap Conditions
26 May 6 G0
27 May 6 G0
28 May 12 G0, chance of G1
COMMENT: G0 geomagnetic conditions were observed in the Australian
and Antarctic regions on UT day 25-May. G0 geomagnetic conditions
are expected over 26-28 May, with a chance of G1 on 28-May due
to coronal hole effects from a recurrent coronal hole feature.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 May Fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 May Normal Normal Normal
27 May Normal Normal Normal
28 May Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 25-May were
normal to fair. HF radio propagation conditions are expected
to be mostly normal over 26-28 May. Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 May 79
Observed Australian Regional MUFs
Cocos Island Region:
Depressed by 15% during local day.
Depressed by 35% during local night.
Northern Australian Region:
Depressed by 15% during local day.
Depressed 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 123
May 113
Jun 111
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
26 May 75 15 to 20% below predicted monthly values
27 May 75 15 to 20% below predicted monthly values
28 May 75 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. Maximum usable frequencies
(MUFs) in the Australian region on UT day 25-May were near predicted
monthly values to 15-35% depressed. Spread F was observed at
Hobart and Brisbane during local night hours. MUFs are expected
to be 15-20% depressed over 26-28 May. Shortwave fadeouts are
probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 May
Daily Proton Fluence >1 MeV:
Daily Proton Fluence >10 MeV:
Daily Electron Fluence >2 MeV:
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background:
DSCOVR Satellite Solar Wind Day Averaged Data for 24 May
Speed: 403 km/sec Density: 2.9 p/cc Temp: 54200 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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