[Ips-dsgr] SWS Daily Report - 20 September 21 issued 2330 UT on 20 Sep 2021

Regional Warning Centre rwc at ips.gov.au
Tue Sep 21 09:30:57 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 20 SEPTEMBER AND FORECAST FOR 21 SEPTEMBER - 23 SEPTEMBER
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
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1A. SOLAR SUMMARY
Activity 20 Sep:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Sep:  79/19


1B. SOLAR FORECAST
             21 Sep             22 Sep             23 Sep
Activity     Very low to low    Very low to low    Very low to low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    75/13              75/13              77/16

COMMENT: Solar activity was very low on UT day 20 September. 
Currently there are three numbered regions on the visible solar 
disk: 2871, 2872 and 2873. Solar activity is expected to be very 
low to low on 21-23 September. No Earth-directed CMEs were observed 
in the available coronagraph data. On 20 September the solar 
wind speed range was 300 km/s to 325 km/s. The total IMF (Bt) 
range was 2-6 nT and the north-south IMF (Bz) component range 
was +3/-4 nT. Solar wind parameters may become disturbed in the 
latter part of 21 September or on 22 September with the arrival 
of the 18 September CME. A mild to moderate increase in the solar 
wind speed is expected for 23 September due to coronal hole effects.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 20 Sep: Quiet

Estimated Indices 20 Sep : A   K           
   Australian Region       1   11000001
      Cocos Island         1   11100000
      Darwin               2   11100002
      Townsville           1   11011001
      Learmonth            1   11100000
      Alice Springs        1   11000001
      Gingin               0   11000000
      Canberra             0   10000001
      Hobart               0   10000001    

Estimated Antarctic Regional K Indices 20 Sep :
      Macquarie Island     0   00000000
      Casey                4   32210002
      Mawson              11   42021134

Observed Regional daily pc3 Indices 20 Sep : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Hobart               0   (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 20 Sep : A 
           Fredericksburg         4
           Planetary              4                         

Observed AFr/Ap Indices 19 Sep :  A   K
           Fredericksburg         2
           Planetary              2   1000 1011     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
21 Sep    11    Quiet to Unsettled
22 Sep    15    Unsettled to Active
23 Sep    11    Unsettled

COMMENT: SWS Geomagnetic Warning 27 was issued on 20 September 
and is current for 21-22 Sep. On UT day 20 September, geomagnetic 
conditions in the Australian region were quiet. In the Antarctic 
region, quiet to active levels were observed. Global geomagnetic 
conditions are expected to be quiet in the first half of 21 September. 
A CME may arrive in the latter half of 21 September or on 22 
September, causing active to minor storm conditions. An increase 
in the geomagnetic activity is likely on 23 September due to 
coronal hole effects.

-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
20 Sep      Normal         Normal         Normal-fair    

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
21 Sep      Normal         Normal         Normal-fair
22 Sep      Normal         Normal         Normal-fair
23 Sep      Normal         Normal         Normal-fair

COMMENT: Mostly normal HF propagation conditions were observed 
on 20 September. Mostly normal conditions are expected on 21-23 
September.

-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
20 Sep    14

Observed Australian Regional MUFs
   Cocos Island Region:
      Depressed by 15% during local day.
      Depressed by 15% during local night.
   Niue Island Region:
      No data available.
   Northern Australian Region:
      Depressed by 20% 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
21 Sep    15    Near predicted monthly values
22 Sep    20    Near predicted monthly values
23 Sep    15    Near predicted monthly values

COMMENT: MUFs in the Australian region on UT day 20 September 
were mostly near predicted monthly values. Mild to moderate depressions 
were observed in the Northern Australian region during local 
day. MUFs in the Australian region on 21-23 September are expected 
to be mostly near predicted monthly values.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 19 Sep
       Daily Proton Fluence >1 MeV:   6.4E+04
       Daily Proton Fluence >10 MeV:  5.0E+04
       Daily Electron Fluence >2 MeV: 1.20E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A3.8

DSCOVR Satellite Solar Wind Day Averaged Data for 19 Sep
Speed: 322 km/sec  Density:    7.0 p/cc  Temp:   140000 K  Bz:   2 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------

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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