[Ips-dsgr] SWS Daily Report - 25 September 21 issued 2330 UT on 25 Sep 2021
Regional Warning Centre
rwc at ips.gov.au
Sun Sep 26 09:30:58 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 25 SEPTEMBER AND FORECAST FOR 26 SEPTEMBER - 28 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 25 Sep: Low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Sep: 88/32
1B. SOLAR FORECAST
26 Sep 27 Sep 28 Sep
Activity Low Low Low
Fadeouts None expected None expected None expected
10.7cm/SSN 88/32 86/29 86/29
COMMENT: Solar activity was low on UT day 25 September. Currently
there are 6 numbered regions on the visible solar disk. AR2871
(S28W16) produced a few weak C-class flares. There was a narrow
CME towards the west in Lasco images around 25/0048 UT, that
appears to have been produced by region 2874 (S23W64) in SDO304
images and further analysis is needed. The filament eruption
at 24/1748 UT was associated with a narrow CME, that has now
been analysed, and could deliver a glancing blow at Earth late
on UT day 27 September. Also there was a filament eruption near
S23W10 around 25/1323 UT observed in H-alpha images. There were
no other Earth-directed CMEs observed in the available coronagraph
data. Solar activity is expected to be low on UT days 26-28 September.
On UT day 25 September, the solar wind speed was between 470
km/s and 570 km/s. The total IMF (Bt) peaked at 6 nT and the
north-south IMF (Bz) component varied between 5 nT and -5 nT.
The solar wind speed may increase from slightly enhanced to moderately
enhanced levels on UT days 26-28 September due to the combined
effects of an extension of a northern polar coronal hole, plus
glancing blows from the 23 September CMEs caused by two M-class
flares and the 24 September filament eruption CME.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 Sep: Quiet
Estimated Indices 25 Sep : A K
Australian Region 5 22221111
Cocos Island 3 21221010
Darwin 5 22221112
Townsville 4 22121111
Learmonth 5 22221220
Alice Springs 5 22221111
Gingin 5 22221220
Canberra 5 22221111
Hobart 5 22221220
Estimated Antarctic Regional K Indices 25 Sep :
Macquarie Island 3 22220010
Casey 16 45431121
Mawson 17 34423134
Observed Regional daily pc3 Indices 25 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 16 (Quiet)
Canberra 14 (Quiet)
Hobart 18 (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 25 Sep : A
Fredericksburg 8
Planetary 8
Observed AFr/Ap Indices 24 Sep : A K
Fredericksburg 6
Planetary 6 2121 1321
2B. MAGNETIC FORECAST
Date Ap Conditions
26 Sep 20 Quiet to active with possible minor to major
storm periods
27 Sep 25 Quiet to active with possible minor to major
storm periods
28 Sep 12 Quiet to unsettled with possible active periods
COMMENT: SWS Geomagnetic Warning 28 was issued on 24 September
and is current for 26-27 Sep. On UT day 25 September, geomagnetic
conditions in the Australian region were quiet. In the Antarctic
region, quiet to active levels were observed with one minor storm
period. Quiet to active conditions with possible minor to major
storm periods are expected for UT days 26-27 September. This
disturbance is due to combined coronal hole plus CME effects.
Then on UT day 28 September, mostly quiet to unsettled conditions
with possible active periods are expected. Auroras may be visible
on the local night of 26 September in Tasmania.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 Sep Normal Normal-fair Fair
27 Sep Fair Fair Fair-poor
28 Sep Normal Normal-fair Fair
COMMENT: Mildly degraded HF propagation conditions are possible
on UT days 26-28 September, due to the expected increase in geomagnetic
activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 Sep 37
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Enhanced by 35% during local night.
Niue Island Region:
No data available.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Aug 14
Sep 27
Oct 30
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
26 Sep 20 Near predicted monthly values/depressed 10 to
20%
27 Sep 15 Near predicted monthly values/depressed 10 to
20%
28 Sep 20 Near predicted monthly values/depressed 10 to
20%
COMMENT: MUFs in the Australian region on UT day 25 September
were mostly near predicted monthly values, with some enhancements
in the Cocos Island region over the UT day and also in the Northern
Australian region during the local day. Some mild MUF depressions
are possible on UT days 26-28 September, due to the expected
increase in geomagnetic activity.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 Sep
Daily Proton Fluence >1 MeV: 1.1E+05
Daily Proton Fluence >10 MeV: 4.4E+04
Daily Electron Fluence >2 MeV: 4.80E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 24 Sep
Speed: 472 km/sec Density: 7.7 p/cc Temp: 210000 K Bz: 2 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Space Weather Services email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386 WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240 AUSTRALIA FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010 fax: +61 2 9213 8060
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