[Ips-dsgr] SWS Daily Report - 26 September 21 issued 2331 UT on 26 Sep 2021
Regional Warning Centre
rwc at ips.gov.au
Mon Sep 27 09:31:01 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 26 SEPTEMBER AND FORECAST FOR 27 SEPTEMBER - 29 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:** RED ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 26 Sep: Low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Sep: 86/29
1B. SOLAR FORECAST
27 Sep 28 Sep 29 Sep
Activity Low Low Low
Fadeouts None expected None expected None expected
10.7cm/SSN 86/29 86/29 84/26
COMMENT: Solar activity was low on UT day 26 September. Currently
there are 7 numbered regions on the visible solar disk. AR2873
(N26W85) produced a C1 flare at 0631 UT and AR2871 (S28W28) produced
a C1.6 flare at 1124 UT. There was a weak narrow CME towards
the southwest in Lasco and Stereo-A images around 26/03 UT, that
appears to have been produced by region 2874 (S23W78) in SDO304
images. There was another weak narrow CME towards the southwest
in Lasco and Stereo-A images around 26/1236 UT. Further analysis
is needed to determine if these CMEs have an Earth directed component.
There were no other CMEs observed in the available coronagraph
data. Solar activity is expected to be low on UT days 27-29 September.
On UT day 26 September, the solar wind speed followed a decreasing
trend from 480 km/s down to 385 km/s. The total IMF (Bt) peaked
at 4 nT and the north-south IMF (Bz) component varied between
3 nT and -2 nT. The solar wind speed may increase from slightly
enhanced to moderately enhanced levels on UT days 27-29 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 26 Sep: Quiet
Estimated Indices 26 Sep : A K
Australian Region 1 11100001
Cocos Island 0 01100000
Darwin 1 11100001
Townsville 1 11000011
Learmonth 1 11100000
Alice Springs 1 11000001
Gingin 1 11100000
Canberra 1 10000011
Hobart 1 10000011
Estimated Antarctic Regional K Indices 26 Sep :
Macquarie Island 0 00000000
Casey 6 33311001
Mawson 4 22001023
Observed Regional daily pc3 Indices 26 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 2 (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 26 Sep : A
Fredericksburg 4
Planetary 4
Observed AFr/Ap Indices 25 Sep : A K
Fredericksburg 7
Planetary 6 2221 1112
2B. MAGNETIC FORECAST
Date Ap Conditions
27 Sep 25 Quiet to active with possible minor to major
storms
28 Sep 12 Mostly quiet to unsettled with possible active
periods
29 Sep 10 Quiet to Unsettled
COMMENT: SWS Geomagnetic Warning 29 was issued on 25 September
and is current for 26-27 Sep. On UT day 26 September, geomagnetic
conditions in the Australian region were quiet. In the Antarctic
region, quiet to unsettled levels were observed. Quiet to active
conditions with possible minor to major storm periods are expected
for UT day 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. On UT day 29 September quiet to unsettled conditions
are expected as coronal hole and CME effects fade. Auroras may
be visible on the local night of 27 September in Tasmania.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
26 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
27 Sep Fair Fair Fair-poor
28 Sep Normal Normal-fair Fair
29 Sep Normal Normal Normal-fair
COMMENT: Mildly degraded HF propagation conditions are possible
on UT days 27-28 September, due to the expected increase in geomagnetic
activity. Then mostly normal HF propagation conditions are expected
on UT day 29 September. Auroras may be visible on the local night
of 27 September in Tasmania.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
26 Sep 26
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 15% during local day.
Depressed by 15% during local night.
Niue Island Region:
No data available.
Northern Australian Region:
Near predicted monthly values.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values.
Monthly T index:
Month T index
Aug 14
Sep 27
Oct 30
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
27 Sep 20 Near predicted monthly values/depressed 10 to
20%
28 Sep 15 Near predicted monthly values/depressed 10 to
20%
29 Sep 20 Near predicted monthly values
COMMENT: MUFs in the Australian region on UT day 26 September
were mostly near predicted monthly values, with some mild depressions
in the Cocos Island region during the local night. Some mild
MUF depressions are possible on UT days 27-28 September, due
to the expected increase in geomagnetic activity. Mostly normal
HF propagation conditions are expected on UT day 29 September.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 25 Sep
Daily Proton Fluence >1 MeV: 5.7E+04
Daily Proton Fluence >10 MeV: 4.3E+04
Daily Electron Fluence >2 MeV: 3.60E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B1.5
DSCOVR Satellite Solar Wind Day Averaged Data for 25 Sep
Speed: 514 km/sec Density: 7.0 p/cc Temp: 258000 K Bz: 1 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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