[Ips-dsgr] ASWFC Daily Report - 20 May 25 issued 2332 UT on 20 May 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Wed May 21 09:32:08 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 MAY AND FORECAST FOR 21 MAY - 23 MAY
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 May: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 May: 118/70
1B. SOLAR FORECAST
21 May 22 May 23 May
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 118/70 120/72 120/72
COMMENT: Solar activity on UT day 20-May was at the R0 level,
with several C-class flares observed. There are currently five
numbered sunspot regions visible on the solar disk and two unnumbered
regions. AR4087 (N17W21, beta) is the largest region on the disk
and has shown decay in its trailer spots. Newly numbered AR4093
(S05E68, beta-gamma) recently rotated over the eastern limb and
has shown recent decay in its trailer spots. An unnumbered region
is visible near N18E55 (beta) and has exhibited spot development.
A second unnumbered region recently appeared near S09E40 (alpha)
and has shown mild growth. All other sunspot regions are either
stable or in decay. Solar activity is expected to be at R0-R1
levels over 21-23 May. No Earth-directed CMEs have been observed.
The solar wind speed on UT day 20-May increased, ranging from
450 to 590 km/s and is currently near 590 km/s. The peak total
interplanetary magnetic field strength (IMF, Bt) was 11 nT and
the north-south IMF component (Bz) range was -8 to +9 nT. The
solar wind speed is expected to remain elevated over 21-23 May
due to ongoing coronal hole high speed wind stream effects from
a southern hemisphere coronal hole.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 May: G0
Estimated Indices 20 May : A K
Australian Region 11 23333222
Cocos Island 5 22222111
Darwin 10 23323222
Townsville 11 23333222
Learmonth 11 23333222
Alice Springs 10 23333212
Gingin 10 23233222
Canberra 8 13323211
Kennaook Cape Grim 11 23333222
Hobart 10 23333221
Estimated Antarctic Regional K Indices 20 May :
Macquarie Island 12 13344211
Casey 13 44332212
Mawson 34 26634235
Observed Regional daily pc3 Indices 20 May :
Darwin 9 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 2 (Quiet)
Gingin 7 (Quiet)
Canberra 24 (Quiet to unsettled)
Hobart 35 (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 20 May : A
Fredericksburg
Planetary
Observed AFr/Ap Indices 19 May : A K
Fredericksburg
Planetary 9 3322 2222
2B. MAGNETIC FORECAST
Date Ap Conditions
21 May 14 G0, chance of G1
22 May 12 G0
23 May 12 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 20-May. Mostly G0 geomagnetic conditions were
observed in the Antarctic region, with isolated periods of G1-G2
observed at Mawson. G0 geomagnetic conditions are expected over
21-23 May, with a chance of G1 on 21-May due to coronal hole
high speed wind stream effects from a southern hemisphere coronal
hole.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 May Normal-fair Normal-fair Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 May Normal Normal Normal-fair
22 May Normal Normal Normal-fair
23 May Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 20-May were
normal to fair. HF radio propagation conditions are expected
to be normal to fair over 21-23 May due to ongoing coronal hole
effects. Shortwave fadeouts are possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 May 87
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 25% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Depressed by 20% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Depressed by 25% during local night.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 15% 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
21 May 90 Depressed 15%/near predicted monthly values
22 May 90 Depressed 15%/near predicted monthly values
23 May 90 Depressed 15%/near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 20-May were near predicted monthly values during
local day and 20-25% depressed during local night. Spread F was
observed at Hobart during local night hours. MUFs are expected
to be near predicted monthly values to 15% depressed over 21-23
May. Shortwave fadeouts are possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 May
Daily Proton Fluence >1 MeV: 1.4E+06
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 7.70E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B5.1
DSCOVR Satellite Solar Wind Day Averaged Data for 19 May
Speed: 513 km/sec Density: 2.1 p/cc Temp: 118000 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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