[Ips-dsgr] ASWFC Daily Report - 21 March 25 issued 2346 UT on 21 Mar 2025 [SEC=OFFICIAL]
Australian Space Weather Forecasting Centre
aswfc at bom.gov.au
Sat Mar 22 10:46:16 AEDT 2025
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 MARCH 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 MARCH AND FORECAST FOR 22 MARCH - 24 MARCH
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Mar: R1
Flares Max Fadeout Freq. Sectors
M1.2 1558UT possible lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Mar: 165/119
1B. SOLAR FORECAST
22 Mar 23 Mar 24 Mar
Activity R0-R1 R0-R1 R0-R1
Fadeouts Possible Possible Possible
10.7cm/SSN 165/119 160/114 155/109
COMMENT: Solar activity on UT day 21-Mar was R1 due to an isolated
M1 flare from AR4028 (S18W34, beta). The M1.2 flare from AR4028
had a parallel ribbon optical structure. Whilst there are numerous
solar regions on the visible solar disk all regions are currently
small and of the more simple alpha and beta magnetic classifications.
Solar regions AR4036 (N07W20, beta) and AR4037 (N19W16, beta)
and AR4031 (N17W61, beta) are growing and AR4033 (N17W19, alpha)
has slightly grown. There are currently thirteen numbered sunspot
regions on the solar disk. All other sunspots are either stable
or in decay. Small localised on disk plasma motion and coronal
diming was observed in SDO193 imagery located at N00-N10E13 at
21/1607UT, occurring nearly simultaneously with the M1.2 flare.
However, no solar activity could be easily identified in SDO/H-alpha
imagery at the location of the on disk diming. Solar activity
is expected to be R0-R1 over 22-24 Mar. A southwest directed
relatively narrow CME first observed in LASCO C2 at 21/1636UT
is considered associated with the M1.2 flare from AR4028. An
earlier more faint southeast directed CME first visible from
21/1600UT, is considered to precede both the M1.2 flare or the
nearby on disk plasma diming and is therefore currently assessed
as a far side event, though there is some assessment uncertainty.
Modelling of the southwest CME which has been paired to the M1
flare shows this CME as an insignificant arrival. Other CMEs
observed on 21-Mar are considered to be farside or non-Earth
directed with a north-northeast CME observed from 21/0912UT and
a very narrow CME to the southeast observed from 21/1336UT. S0
solar radiation storm conditions were observed on UT day 21-Mar,
with a weak proton flux enhancement of 1PFU observed after 21/1400UT.
The flare from AR4028 may have contributed to the minor proton
flux enhancement. S0 solar radiation storm conditions are expected
over 22-24 Mar. A weak shock was observed at 21/0142UT with the
solar wind speed only slightly increasing and then declining
after the shock arrival. The solar wind parameters then became
enhanced late in the UT day on 21-Mar. In particular the interplanetary
magnetic field became very enhanced during the interval 21/1700-1800UT,
though with a predominately northward orientation. The ACE EPAM
data indicates a brief energetic ion enhancement event at around
21/1605UT, possibly suggesting another weak CME transient. The
gradual rise of the solar wind speed from 21/1300UT may also
suggest an earlier than expected entry into a coronal hole wind
stream, with the enhanced solar wind parameters observed late
in the UT day then possibly due to both a corotating interactive
region in the solar wind and a second weak indistinct CME signature.
The peak total interplanetary field strength (IMF, Bt) was 40
nT and the north-south IMF component range (Bz) was 33 to -20
nT. The solar wind speed may become mildly disturbed on 22-Mar
due to another possible weak CME transient. The solar wind may
remain elevated over 22-23 Mar due to the influence of a coronal
hole wind stream from a equatorial coronal hole now located west
of the solar central meridian. Additional coronal holes are visible
in the southeast solar quadrant.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 21 Mar: G1
Estimated Indices 21 Mar : A K
Australian Region 16 32223353
Cocos Island 16 32222453
Darwin 21 43233453
Townsville 22 43233454
Learmonth 23 53233453
Alice Springs 18 33233353
Gingin 16 32223353
Canberra 14 32222344
Kennaook Cape Grim 11 32222333
Hobart 11 32222243
Estimated Antarctic Regional K Indices 21 Mar :
Macquarie Island 10 32122333
Casey 17 43332343
Mawson 26 45423354
Observed Regional daily pc3 Indices 21 Mar :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 3 (Quiet)
Alice Springs 0 (Quiet)
Gingin 14 (Quiet)
Canberra 32 (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 21 Mar : A
Fredericksburg 18
Planetary 27
Observed AFr/Ap Indices 20 Mar : A K
Fredericksburg 5
Planetary 8 2221 3222
2B. MAGNETIC FORECAST
Date Ap Conditions
22 Mar 14 G0, chance G1
23 Mar 14 G0, chance G1
24 Mar 10 G0
COMMENT: G1 geomagnetic conditions were briefly observed in the
Australian region on UT day 21-Mar. A weak (12nT) impulse was
observed at 21/0238UT in Bureau magnetometer data. In the Antarctic
region G1 periods were observed at Mawson and G0 conditions were
observed at Casey and Macquarie Island. G0 geomagnetic conditions
are mostly expected over 22-24 Mar, with a chance for G1 periods
during 22-23 Mar due to a possible weak influence from a CME
and coronal hole wind stream effects.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
21 Mar Normal Fair-normal Fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
22 Mar Normal Fair-normal Fair
23 Mar Normal Fair-normal Fair
24 Mar Normal Normal Normal-fair
COMMENT: HF radio propagation conditions on UT day 21-Mar were
fair to normal, with fair conditions observed at middle to high
latitudes. HF radio propagation conditions are expected to be
fair to normal over 22-24 Mar, with mildly degraded conditions
at middle to high latitudes on 22-Mar and 23-Mar.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
21 Mar 151
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Near predicted monthly values during local night.
Enhanced by 20% after local dawn.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 35% during local night.
Northern Australian Region:
Enhanced by 15% during local day.
Enhanced by 30% during local night.
Southern Australian Region:
Enhanced by 15%.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Feb 127
Mar 117
Apr 114
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
22 Mar 135 Near predicted monthly values to 15% enhanced
23 Mar 135 Near predicted monthly values to 15% enhanced
24 Mar 135 Near predicted monthly values to 15% enhanced
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 21-Mar were near predicted values to 15% enhanced.
Enhancements of up to 30% have been observed after dawn this
morning at some Australian east coast sites. Mild spread-F was
observed in Hobart during local night hours. Scintillation was
observed at Weipa during the interval 21/1151-1310UT. MUFs are
expected to be generally near predicted values to 15% enhanced
over 22-24 Mar, with brief mild depressions of 15% possible after
local dawn for the southern Australian region during 23-24 Mar.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 20 Mar
Daily Proton Fluence >1 MeV: 2.1E+06
Daily Proton Fluence >10 MeV: 2.0E+04
Daily Electron Fluence >2 MeV: 2.30E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 4%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 20 Mar
Speed: 430 km/sec Density: 6.3 p/cc Temp: 157000 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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