[Ips-dsgr] ASWFC Daily Report - 17 May 25 issued 2331 UT on 17 May 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sun May 18 09:31:28 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 MAY AND FORECAST FOR 18 MAY - 20 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 May: 117/69
1B. SOLAR FORECAST
18 May 19 May 20 May
Activity R0-R1, chance R2 R0-R1, chance R2 R0-R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 118/70 120/72 115/66
COMMENT: Solar activity on UT day 17-May was at the R0 level
with a declining background X-Ray flux. There are currently three
numbered sunspot regions visible on the solar disk and one unnumbered
region. AR4087 (N17E32, beta-delta) is the largest and most magnetically
complex region on the solar disk and has been responsible for
several M-class flares and one X-class flare since arriving on
the solar disk. This region appeared to grow over the UT day
but declined in magnetic complexity. All other numbered regions
appeared stable. An unnumbered region has developed on the solar
disk at around S16E42 with beta magnetic characteristics. Solar
activity is expected to be at R0-R1 levels, with a chance of
R2 over 18-20 May. S0 solar radiation conditions were observed
on 17-May, S0 conditions are expected over 18-20 May. No Earth-directed
CMEs have been observed. The solar wind speed on UT day 17-May
increased significantly, mostly ranging between 400 to 800 km/s
and is currently near 725 km/s. The peak total interplanetary
magnetic field strength (IMF, Bt) was 22 nT and the north-south
IMF component (Bz) range was -18 to +16 nT. The increase in speed
and IMF strength is due to coronal hole high speed wind stream
effects, combined with a glancing impact from a CME first observed
on 13-May. The solar wind environment is expected to remain enhanced
over 18-20 May due to high speed wind stream effects from a large
coronal hole in the southern hemisphere.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 May: G0
Estimated Indices 17 May : A K
Australian Region 18 34344332
Cocos Island 16 34334322
Darwin 22 35344333
Townsville 22 35344432
Learmonth 25 35345432
Alice Springs 17 34344322
Gingin 21 44344333
Canberra 18 34344332
Kennaook Cape Grim 23 34355332
Hobart 23 34355332
Estimated Antarctic Regional K Indices 17 May :
Macquarie Island 41 55456542
Casey 16 34343322
Mawson 47 75444426
Observed Regional daily pc3 Indices 17 May :
Darwin 13 (Quiet)
Townsville 4 (Quiet)
Learmonth 6 (Quiet)
Alice Springs 7 (Quiet)
Gingin 24 (Quiet to unsettled)
Canberra 64 (Active)
Hobart 141 (Severe storm)
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 17 May : A
Fredericksburg 32
Planetary 50
Observed AFr/Ap Indices 16 May : A K
Fredericksburg 11
Planetary 13 2232 3224
2B. MAGNETIC FORECAST
Date Ap Conditions
18 May 30 G0-G1
19 May 20 G0, chance of G1
20 May 20 G0, chance of G1
COMMENT: ASWFC Geomagnetic Warning 38 was issued on 17 May and
is current for 17-19 May. Mostly G0 geomagnetic conditions were
observed in the Australian region on UT day 17-May, with G1 conditions
observed at Hobart, Kennaook Cape Grim and Learmonth. Mostly
G2 geomagnetic conditions were observed in the Antarctic region,
with a period of G3 observed at Mawson. G0-G1 conditions are
expected on 18-May and G0 conditions, with a chance of G1 are
expected on 19-20 May due to coronal hole high speed wind stream
effects combined with ongoing CME impact effects.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 May Fair Fair-poor Poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 May Fair Fair Fair-poor
19 May Normal Normal-fair Fair
20 May Normal Normal-fair Fair
COMMENT: HF radio propagation conditions on UT day 17-May were
mostly fair at low to mid latitudes and mostly poor at high latitudes.
HF radio propagation conditions are expected to be mostly fair
over 18-19 May, recovering towards mostly normal on 20-May. The
strongest degradations are expected at high latitudes. Shortwave
fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 May 92
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 30% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 30% 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.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 40% 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
18 May 90 Depressed 15%/near predicted monthly values
19 May 90 Depressed 15%/near predicted monthly values
20 May 100 Near predicted monthly values
COMMENT: ASWFC HF Communications Warning 48 was issued on 16
May and is current for 17-19 May. Maximum usable frequencies
(MUFs) in the Australian region on UT day 17-May were near predicted
monthly values in the southern Australian region, with depressions
of 35% observed in the northern Australian region during local
night. Spread F was observed at Hobart and Brisbane during local
night hours. Sporadic E was also observed at Brisbane. MUFs are
expected to be near predicted monthly values to 15% depressed
over 18-19 May. A recovery towards monthly predicted values is
expected on 20-May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 May
Daily Proton Fluence >1 MeV: 3.4e+05
Daily Proton Fluence >10 MeV: 1.5e+04
Daily Electron Fluence >2 MeV: 1.50e+07
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B4.3
DSCOVR Satellite Solar Wind Day Averaged Data for 16 May
Speed: 416 km/sec Density: 6.0 p/cc Temp: 97100 K Bz: -4 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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