[Ips-dsgr] SWS Daily Report - 24 September 21 issued 2331 UT on 24 Sep 2021
Regional Warning Centre
rwc at ips.gov.au
Sat Sep 25 09:31:01 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/24 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 24 SEPTEMBER AND FORECAST FOR 25 SEPTEMBER - 27 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
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1A. SOLAR SUMMARY
Activity 24 Sep: Low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Sep: 88/32
1B. SOLAR FORECAST
25 Sep 26 Sep 27 Sep
Activity Low to moderate Low to moderate Low to moderate
Fadeouts Possible Possible Possible
10.7cm/SSN 88/32 86/29 82/23
COMMENT: Solar activity was low on UT day 24 September. Currently
there are 5 numbered regions on the visible solar disk. AR2871
produced a C2.9 flare at 0701 UT and could produce more M-class
flares. There was a narrow CME towards the west in Lasco & Stereo-A
images starting at 24/1248 UT, but a source could not be found
on the visible disk and it is unlikely to have an Earth directed
component. Also there was a filament eruption near E05S23 around
24/1440 UT observed in H-alpha images. There was another filament
eruption observed in SDO images near S30W05 around 24/1748 UT.
No Earth-directed CMEs were observed in the available coronagraph
data over the previous 24 hours. Solar activity is expected to
be low to moderate on UT days 25-27 September. On UT day 24 September,
the solar wind speed followed an increasing trend from 400 km/s
up to 500 km/s. The total IMF (Bt) peaked at 10 nT and the north-south
IMF (Bz) varied between 7 nT and -5 nT. For UT day 25 September,
light to moderate solar wind speeds are expected. The solar wind
parameters may become disturbed on UT days 26-27 September due
to the combined effects of a northern polar coronal hole with
extension down to low latitudes, plus a glancing blow from the
23 September CMEs caused by two M-class flares.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 24 Sep: Quiet to Unsettled
Estimated Indices 24 Sep : A K
Australian Region 5 22210301
Cocos Island 4 12210300
Darwin 6 22211302
Townsville 6 22221311
Learmonth 5 22211300
Alice Springs 5 22210301
Gingin 6 22210401
Canberra 4 22210300
Hobart 5 21210311
Estimated Antarctic Regional K Indices 24 Sep :
Macquarie Island 6 11201420
Casey 17 45431311
Mawson 13 33221334
Observed Regional daily pc3 Indices 24 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 32 (Quiet to unsettled)
Canberra 11 (Quiet)
Hobart 34 (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 24 Sep : A
Fredericksburg 7
Planetary 10
Observed AFr/Ap Indices 23 Sep : A K
Fredericksburg 10
Planetary 8 2242 2111
2B. MAGNETIC FORECAST
Date Ap Conditions
25 Sep 10 Quiet to Unsettled
26 Sep 20 Quiet to Active with possible isolated minor
storms
27 Sep 20 Quiet to Active with possible isolated minor
storms
COMMENT: On UT day 24 September, geomagnetic conditions in the
Australian region were mostly quiet to unsettled. In the Antarctic
region, quiet to active levels were observed with one minor storm
period. Quiet to unsettled conditions are expected for UT day
25 September. An increase in geomagnetic activity up to unsettled
and active levels with possible isolated minor storms is expected
on UT days 26-27 September. This disturbance is due to the combined
effects of a northern polar coronal hole with extension down
to low latitudes, plus a glancing blow from the 23 September
CMEs caused by two M-class flares.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
24 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
25 Sep Normal Normal Normal-fair
26 Sep Normal Normal-fair Fair
27 Sep Normal Normal-fair Fair
COMMENT: Mostly normal HF propagation conditions are expected
on UT day 25 September. There is a chance of Short-wave fadeouts
on UT days 25-27 September. Mildly degraded conditions are likely
on UT days 26-27 September due to the expected increase in geomagnetic
activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
24 Sep 31
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Niue Island Region:
No data available.
Northern Australian Region:
Depressed by 15% during local day.
Enhanced by 20% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 15% during local night.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Enhanced by 15% 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
25 Sep 25 Near predicted monthly values
26 Sep 20 Near predicted monthly values/depressed 10 to
20%
27 Sep 15 Near predicted monthly values/depressed 10 to
20%
COMMENT: SWS SWF HF Communications Warning 24 was issued on 23
September and is current for 23-25 Sep. MUFs in the Australian
region on UT day 24 September were mostly near predicted monthly
values, with some enhancements during the local night. There
were also some mild MUF depressions during the local day in the
Northern Australian region. MUFs in the Australian region are
expected to be near predicted monthly values on UT day 25 September.
Some mild MUF depressions are possible on UT days 26-27 September
due to the expected increase in geomagnetic activity.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 23 Sep
Daily Proton Fluence >1 MeV: 1.3E+05
Daily Proton Fluence >10 MeV: 4.6E+04
Daily Electron Fluence >2 MeV: 1.60E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B1.3
DSCOVR Satellite Solar Wind Day Averaged Data for 23 Sep
Speed: 383 km/sec Density: 10.0 p/cc Temp: 69900 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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