[Ips-dsgr] ASWFC Daily Report - 22 September 23 issued 2330 UT on 22 Sep 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sat Sep 23 09:30:09 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/22 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 22 SEPTEMBER AND FORECAST FOR 23 SEPTEMBER - 25 SEPTEMBER
STATUS INDICATORS SOL:** RED ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 22 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.2 0337UT possible lower E. Asia/Aust.
M1.4 1624UT possible lower South American/
Atlantic
M1.9 2300UT possible lower West Pacific
Observed 10.7 cm flux/Equivalent Sunspot Number for 22 Sep: 176/130
1B. SOLAR FORECAST
23 Sep 24 Sep 25 Sep
Activity R1-R2, chance R3 R1-R2, chance R3 R1-R2, chance R3
Fadeouts Probable Probable Probable
10.7cm/SSN 178/131 175/129 172/126
COMMENT: Solar activity on UT day 22-Sep was R1, with several
low-level M-class flares. AR3435 (N10E02, beta) and AR3443 (N28W39,
beta) were responsible for these flares. There are currently
twelve sunspot regions on the solar disk, several of which are
magnetically complex. AR3435, which was responsible for a long-duration
M1 flare has shown some growth in its trailer spots; AR3441 (N07W30,
beta) has had some minor growth and decay; AR3443 (N28W41, beta)
has grown and AR3445 (S13E35, beta-gamma) has also grown. Solar
activity over 23-25 Sep is expected to be R1-R2 with a chance
for R3.
CME activity on 22-Sep was complex and many CMEs were
observed. CMEs observed in the south-southeast from 21/2124 UT,
in the southwest from 22/0248 UT, in the northeast from 22/0248
UT and to the west from 22/0636 UT may be attributed to filament
eruptions.
A CME to the southwest from 22/0824 UT may be associated
with activity that occurred near AR3435, where coronal dimming
directed to the southwest can be observed. A glancing blow from
this CME may be expected from 2300 UT 25-Sep, although confidence
is low on the strength of impact.
A CME to the south-southwest from 22/1712 UT may be associated
with activity from AR3443, and a CME to the east from 22/2136 UT
may be associated with a prominence eruption. A CME associated
with an M8 flare on 21-Sep has been re-analysed and may have a
possible Earth-directed component to arrive on 25-Sep, although
confidence is low. An M1.8 flare was observed from 22/2253 UT
from AR3425, and while no associated CME can be confirmed at
this early stage, any CME may have a geoeffective component given
its location.
Overall, modelling suggests an impact from only one or two of these CMEs,
however given the large amount of activity there is uncertainty regarding
further impacts.
The solar wind on UT day 22-Sep was generally
unremarkable, with a steady speeds reaching a maximum of 426
km/s. The peak total interplanetary field strength (IMF, Bt)
was 5 nT and the north-south IMF component range was +3 to -5
nT. The solar wind speed is expected to increase on 23-Sep due
to an equatorial coronal hole currently near W50. Solar wind
speeds are likely to continue to stay elevated over 24-25 Sep
due to possible CME impacts.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 22 Sep: G0
Estimated Indices 22 Sep : A K
Australian Region 7 11233211
Cocos Island 6 12122311
Darwin 7 11233212
Townsville 8 11233222
Learmonth 9 21233321
Alice Springs 6 11133211
Gingin 9 21133322
Canberra 5 11232111
Hobart 5 11232111
Estimated Antarctic Regional K Indices 22 Sep :
Macquarie Island 13 01354310
Casey 10 34222222
Mawson 24 33322446
Observed Regional daily pc3 Indices 22 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 16 (Quiet)
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 22 Sep : A
Fredericksburg 7
Planetary 8
Observed AFr/Ap Indices 21 Sep : A K
Fredericksburg 10
Planetary 14 2221 4433
2B. MAGNETIC FORECAST
Date Ap Conditions
23 Sep 16 G0-G1
24 Sep 18 G0-G1, slight chance G2
25 Sep 16 G0-G1, slight chance G2
COMMENT: ASWFC Geomagnetic Warning 55 was issued on 22 September
and is current for 22-24 Sep. On UT day 22-Sep, G0 geomagnetic
conditions were observed in the Australian region. Mostly G0
geomagnetic conditions were observed in the Antarctica region,
with an isolated period of G2 in Mawson. Generally G0 geomagnetic
conditions are expected over 23-25 Sep, however periods of G1
are possible due to a coronal hole wind stream expected to come
into effect by 23-Sep. Some further geomagnetic activity from
recent CMEs is possible over 24-25 Sep, however confidence is
low. If CME activity does eventuate, there is a slight chance
for isolated periods of G2 due to being in combination with a
coronal hole wind stream. Two separate CME impacts may occur
on 25-Sep, one at the beginning of the UT day and one at the
end.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
22 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
23 Sep Normal Normal Normal-fair
24 Sep Normal Normal-fair Normal-fair
25 Sep Normal Normal-fair Normal-fair
COMMENT: HF radio propagation conditions on UT day 22-Sep were
normal. Mildly degraded conditions are possible during local
night hours over 23-25 Sep for middle to high latitudes due to
possible geomagnetic activity. Shortwave fadeouts are probable.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
22 Sep 109
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 20% during local day.
Enhanced by 15% during local night.
Niue Island Region:
Enhanced by 20% during local day.
Enhanced by 20% during local night.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 115
Sep 96
Oct 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
23 Sep 110 Near predicted monthly values
24 Sep 105 Near predicted monthly values to 10-15% depressed
25 Sep 95 Near predicted monthly values to 10-15% depressed
COMMENT: Maximum usable frequencies (MUFs) in the Australian
region on UT day 22-Sep were near predicted values. Brief spread-F
was observed in Hobart and Perth during local dawn hours, but
otherwise ionospheric conditions were good. A minor HF fadeout
was observed over the Australian region from 22/0306-0415 UT.
MUFs are expected to be near predicted values over 23-25 Sep,
with possible depressions of 10-15% during local night hours
due to possible geomagnetic activity over this period. Shortwave
fadeouts are probable.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 21 Sep
Daily Proton Fluence >1 MeV: 8.3E+04
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 2.80E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 4%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.1
DSCOVR Satellite Solar Wind Day Averaged Data for 21 Sep
Speed: 424 km/sec Density: 0.2 p/cc Temp: 53500 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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