[Ips-dsgr] ASWFC Daily Report - 28 May 25 issued 2330 UT on 28 May 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu May 29 09:30:47 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/28 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 28 MAY AND FORECAST FOR 29 MAY - 31 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 28 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 28 May: 144/98
1B. SOLAR FORECAST
29 May 30 May 31 May
Activity R1-R2 R1-R2 R1-R2
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 138/92 135/89
COMMENT: Solar activity on UT day 28-May was at the R0 level,
with several low level C-class flares observed. There are currently
seven numbered sunspot regions visible on the solar disk. AR4100
(N07E44, beta-gamma-delta) is the most magnetically complex region
on the disk and has shown mild growth in its trailer spots. AR4099
(S14E29, beta-delta) has exhibited spot growth over the 24-hour
period. AR4101 (N03E33, beta) has shown mild growth. All other
sunspot regions are either stable or in decay. Solar activity
is expected to be at R1-R2 levels over 29-31 May. No Earth-directed
CMEs have been observed. The solar wind speed on UT day 28-May
declined, ranging from 380 to 620 km/s and is currently near
415 km/s. The peak total interplanetary magnetic field strength
(IMF, Bt) was 22 nT and the north-south IMF component (Bz) range
was -9 to +12 nT. A sustained period of southward IMF conditions
was observed over the interval 28/1444-1907UT. The solar wind
speed is expected to increase over 29-31 May due to coronal hole
high speed wind stream effects from an equatorial coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 28 May: G0
Estimated Indices 28 May : A K
Australian Region 11 33231332
Cocos Island 8 22230322
Darwin 11 33221333
Townsville 10 33221323
Learmonth 9 32221332
Alice Springs 11 33321332
Gingin 11 33231332
Canberra 11 33230332
Kennaook Cape Grim 12 33331332
Hobart 12 33331332
Estimated Antarctic Regional K Indices 28 May :
Macquarie Island 27 35452533
Casey 13 33332332
Mawson 26 45432453
Observed Regional daily pc3 Indices 28 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 4 (Quiet)
Alice Springs 0 (Quiet)
Gingin 49 (Unsettled)
Canberra 53 (Unsettled)
Hobart 38 (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 28 May : A
Fredericksburg 19
Planetary 21
Observed AFr/Ap Indices 27 May : A K
Fredericksburg 15
Planetary 0 ---- ----
2B. MAGNETIC FORECAST
Date Ap Conditions
29 May 20 G1, slight chance of G2
30 May 18 G0-G1
31 May 16 G0, chance of G1
COMMENT: ASWFC Geomagnetic Warning 39 was issued on 28 May and
is current for 28-30 May. G0 geomagnetic conditions were observed
in the Australian region on UT day 28-May. G0-G1 geomagnetic
conditions were observed in the Antarctic region. G1 geomagnetic
conditions are expected on 29-May, with a slight chance of G2
due to coronal hole high speed wind stream effects. G0-G1 geomagnetic
conditions are expected on 30-May. G0 geomagnetic conditions
are expected on 31-May, with a chance of G1.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
28 May Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
29 May Normal Normal-fair Fair
30 May Normal Normal-fair Fair
31 May Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 28-May were
mostly normal, with fair conditions at higher latitudes. HF radio
propagation conditions are expected to be normal to fair over
29-31 May, with degraded conditions possible at high latitudes.
Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
28 May 98
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 45% during local night.
Northern Australian Region:
Near predicted monthly values 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):
Depressed by 30% 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
29 May 80 15 to 20% below predicted monthly values
30 May 80 15 to 20% below predicted monthly values
31 May 90 Depressed 15%/near predicted monthly values
COMMENT: ASWFC HF Communications Warning 54 was issued on 28
May and is current for 28-30 May. ASWFC SWF HF Communications
Warning 55 was issued on 28 May and is current for 28-30 May.
Maximum usable frequencies (MUFs) in the Australian region on
UT day 28-May were near predicted monthly values during local
day and 15-35% depressed during local night. Spread F was observed
at Hobart and Townsville during local night hours. MUFs are expected
to be 15-20% depressed over 29-30 May, and near predicted monthly
values to 15% depressed on 31-May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 27 May
Daily Proton Fluence >1 MeV: 3.5E+05
Daily Proton Fluence >10 MeV: 1.5E+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: B8.8
DSCOVR Satellite Solar Wind Day Averaged Data for 27 May
Speed: 429 km/sec Density: 7.2 p/cc Temp: 46600 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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