[Ips-dsgr] ASWFC Daily Report - 16 April 25 issued 2330 UT on 16 Apr 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Thu Apr 17 09:30:56 AEST 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 APRIL 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 16 APRIL AND FORECAST FOR 17 APRIL - 19 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 16 Apr: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Apr: 148/102
1B. SOLAR FORECAST
17 Apr 18 Apr 19 Apr
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 155/109 150/105 150/105
COMMENT: On UT day 16-Apr solar activity was R0, with no significant
solar flares. There are currently four numbered sunspots on the
disk. AR4062 (S02E64, beta-gamma) is the most complex region
currently on the disk, and has shown only minor changes to its
spots in the last day. All other sunspots are either stable or
in decay. Solar activity is expected to be R0-R1 over 17-19 Apr.
No CMEs were observed on UT day 16-Apr.
S0 solar radiation storm conditions were observed on UT day
16-Apr. S0 solar radiation storm conditions are expected over 17-19 Apr.
The solar wind environment on UT day 16-Apr was disturbed due to a CME arrival
the day prior. The solar wind speed was on a steady decline,
but began near 670 km/s and has trended to near 450 km/s. The
peak total interplanetary field strength (IMF, Bt) was 25 nT
and the north-south IMF component range was +14 to -16 nT. Solar
wind parameter Bz was oriented southward from 1050 to 1950 UT
on 16-Apr. The solar wind strength is expected to continue declining
to near background levels on 17-Apr, however a brief increase
to the solar wind speed is possible due to a small coronal hole.
Otherwise, no further disturbances to the solar wind are expected.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 16 Apr: G1
Estimated Indices 16 Apr : A K
Australian Region 33 43445554
Cocos Island 25 33445443
Darwin 30 44445453
Townsville 34 44454554
Learmonth 38 43456553
Alice Springs 33 33455553
Gingin 38 43346563
Canberra 30 33345554
Kennaook Cape Grim - --------
Hobart 31 33335555
Estimated Antarctic Regional K Indices 16 Apr :
Macquarie Island 48 34336763
Casey 23 54433343
Mawson 44 44344376
Observed Regional daily pc3 Indices 16 Apr :
Darwin 8 (Quiet)
Townsville 5 (Quiet)
Learmonth 13 (Quiet)
Alice Springs 22 (Quiet to unsettled)
Gingin 66 (Active)
Canberra 61 (Active)
Hobart 140 (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 16 Apr : A
Fredericksburg 26
Planetary 41
Observed AFr/Ap Indices 15 Apr : A K
Fredericksburg 0
Planetary 0 3221 3455
2B. MAGNETIC FORECAST
Date Ap Conditions
17 Apr 32 Initially near G4-G3, then G0-G1 by the end of
the day
18 Apr 12 G0
19 Apr 8 G0
COMMENT: ASWFC Geomagnetic Warning 31 was issued on 16 April
and is current for 16-18 Apr. G1 geomagnetic conditions were
observed in the Australian region on UT day 16-Apr, with periods
of G2 in Learmonth and Gingin. Planetary conditions reached G4.
Antarctic conditions reached G3. While the solar wind strength
was only moderate, there was a sustained period of southward
Bz on 16-Apr. Planetary conditions are expected to be near G3-G4
at the beginning of the UT day 17-Apr, however will likely return
to G0-G1 by the second half of the day. G0 geomagnetic conditions
are expected over 18-19 Apr.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
16 Apr Normal-fair Fair Fair-poor
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
17 Apr Normal-fair Normal-fair Fair
18 Apr Normal Normal Normal-fair
19 Apr Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 16-Apr were
normal to fair in low and mid latitudes, and poor in high latitudes
due to geomagnetic activity. HF radio propagation conditions
are expected to continue to be degraded on ut day 17-Apr, however
are expected to improve in the second half of the day. Scintillation
is possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
16 Apr 102
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Niue Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Northern Australian Region:
Mostly near predicted monthly values.
Southern Australian Region:
Mostly near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 25% over the UT day.
Monthly T index:
Month T index
Mar 126
Apr 115
May 113
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
17 Apr 75 Depressed 30 to 40%/near predicted monthly values
18 Apr 90 Depressed 10 to 20%/near predicted monthly values
19 Apr 100 Depressed 10 to 20%/near predicted monthly values
COMMENT: ASWFC HF Communications Warning 40 was issued on 16
April and is current for 17-19 Apr. Maximum usable frequencies
(MUFs) on UT day 16-Apr were mostly near predicted values. Spread-F
was observed in Hobart. HF radio conditions are expected to become
depressed by 30-40% on UT day 17-Apr due to recent geomagnetic
activity. Conditions are likely to be degraded and further spread-F
is expected. High latitude scintillation is possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 15 Apr
Daily Proton Fluence >1 MeV: 6.7E+06
Daily Proton Fluence >10 MeV: 1.5E+04
Daily Electron Fluence >2 MeV: 5.90E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 8%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.4
DSCOVR Satellite Solar Wind Day Averaged Data for 15 Apr
Speed: 425 km/sec Density: 3.5 p/cc Temp: 128000 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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