[Ips-dsgr] SWS Daily Report - 17 September 21 issued 2353 UT on 17 Sep 2021
rwc
rwc at ips.gov.au
Sat Sep 18 09:53:10 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 17 SEPTEMBER AND FORECAST FOR 18 SEPTEMBER - 20 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: ** YELLOW **
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1A. SOLAR SUMMARY
Activity 17 Sep: Low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Sep: 73/9
1B. SOLAR FORECAST
18 Sep 19 Sep 20 Sep
Activity Very low to low Very low to low Very low to low
Fadeouts None expected None expected None expected
10.7cm/SSN 78/17 78/17 76/14
COMMENT: Solar activity was low on UT day 17 September with a
C3.5 flare at 17/0420 UT from over the southeast limb. A type
II sweep was observed 17/0417-0427 UT with estimated shock speed
of 582 km/s. The visible disk of the Sun is spotless with no
active regions. Solar activity is expected to be very low to
low on 18-20 September. A southeast CME was first observed in
LASCO C2 at 0428 UT and is likely associated with the C3.5 flare.
A narrow CME observed at 0438 UT on the northeast limb may be
associated with a prominence eruption on the limb. There was
also a very faint CME signature to the south in LASCO C3 at 0454
UT. There was a filament eruption in the southeast quadrant ending
around 17/0130 UT which may have been the origin of this CME
but there are no STEREO A images to confirm at this stage. A
glancing blow early on 20 Sep is possible from the CME associated
with the C3.5 flare. On UT day 17 September, a step occurred
in solar wind parameters at 0130 UT, probably signalling the
arrival of the 13 September CME. The solar wind speed range was
290 km/s to 419 km/s. The total IMF (Bt) peaked at 15 nT and
the north-south component (Bz) varied in the range -14/+12 nT,
mostly southward after 0130 UT. Over UT day 18 September the
solar wind parameters are expected to be mildly elevated due
to a coronal hole wind stream and the subsiding effects of the
CME. Conditions should be settled on 19 September.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 17 Sep: Quiet to Active
Estimated Indices 17 Sep : A K
Australian Region 12 22132343
Cocos Island 8 22122332
Darwin 11 33122333
Townsville 12 33132333
Learmonth 15 32133344
Alice Springs 12 22132343
Gingin 13 22133343
Canberra 11 22132243
Hobart 13 22043243
Estimated Antarctic Regional K Indices 17 Sep :
Macquarie Island 27 23065443
Casey 14 34232333
Mawson 34 35223466
Observed Regional daily pc3 Indices 17 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 14 (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 17 Sep : A
Fredericksburg 0
Planetary 0
Observed AFr/Ap Indices 16 Sep : A K
Fredericksburg 3
Planetary 3 3
2B. MAGNETIC FORECAST
Date Ap Conditions
18 Sep 13 Quiet to Active. Chance of an isolated minor
storm period.
19 Sep 8 Quiet to Unsettled
20 Sep 7 Quiet
COMMENT: On UT day 17 September, geomagnetic conditions in the
Australian region were quiet to active. In the Antarctic region,
quiet to major storm levels were observed. A weak (8 nT) impulse
was observed at 17/0219 UT in the SWS magnetometer data. Geomagnetic
conditions are expected to be at quiet to active with a chance
of an isolated minor storm period on 18 September as the CME
effects pass and an expected weak coronal hole wind stream. Mostly
quiet conditions are expected on 19-20 September.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
17 Sep Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
18 Sep Normal-fair Normal-fair Normal-fair
19 Sep Normal Normal Normal-fair
20 Sep Normal Normal Normal
COMMENT: Normal to fair conditions are expected on 18 September
with mild to moderate MUF depressions. Conditions on 19-20 September
are expected to be mostly normal.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
17 Sep 14
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 25% during local night.
Niue Island Region:
No data available.
Northern Australian Region:
Depressed by 15% during local day.
Depressed by 20% during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Enhanced by 30% 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
18 Sep 5 Near predicted monthly values/depressed 15 to
25%
19 Sep 15 Near predicted monthly values
20 Sep 15 Near predicted monthly values
COMMENT: MUFs in the Australian region on UT day 17 September
were mostly near predicted monthly values. Some moderately depressed
MUFs were observed in the Cocos Island region during the local
night. MUFs in the Australian region on UT days 18-20 September
are expected to be near predicted monthly values to mildly depressed.
Moderate depressions likely on 18 September.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 16 Sep
Daily Proton Fluence >1 MeV: NA
Daily Proton Fluence >10 MeV: NA
Daily Electron Fluence >2 MeV: NA
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: NA
DSCOVR Satellite Solar Wind Day Averaged Data for 16 Sep
Speed: 324 km/sec Density: 6.9 p/cc Temp: 186000 K Bz: 0 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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