[Ips-dsgr] SWS Daily Report - 18 September 21 issued 2335 UT on 18 Sep 2021

rwc rwc at ips.gov.au
Sun Sep 19 09:35:19 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/18 SEPTEMBER 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 18 SEPTEMBER AND FORECAST FOR 19 SEPTEMBER - 21 SEPTEMBER
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
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1A. SOLAR SUMMARY
Activity 18 Sep:  Low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Sep:  74/11


1B. SOLAR FORECAST
             19 Sep             20 Sep             21 Sep
Activity     Very low to low    Very low to low    Very low to low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    76/14              76/14              76/14

COMMENT: Solar activity was low on UT day 18 September with a 
C2.6 flare at 18/0827 UT from the southeast limb. An unnumbered 
spot region has rotated onto the disc near latitude S29 and is 
the likely origin of the flare. Solar activity is expected to 
be very low to low on 19-21 September. There were a number of 
CMEs. A halo CME at 18/0312 UT is a far side event. A southwest 
CME at 18/1224 UT also appears to be a far side event while a 
southeast CME observed at 18/1524 UT is likely linked to a filament 
disappearance from the vicinity of S41E28 at 1425 UT. Modelling 
indicates this CME may impact on 21 September. The CME from the 
C3.5 flare on 17 September is not expected to be geoeffective. 
On 18 September the solar wind speed range was 341 km/s to 426 
km/s. The total IMF (Bt) peaked at 15 nT early in the period 
but has since settled to less than 5 nT. Solar wind parameters 
are expected to be settled on 19 and 20 September. Solar wind 
parameters may become disturbed in the latter part of 21 September 
with the arrival of the CME.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 18 Sep: Quiet to Unsettled

Estimated Indices 18 Sep : A   K           
   Australian Region       6   23232001
      Cocos Island         6   -4222000
      Darwin               7   33232001
      Townsville          10   33342011
      Learmonth            8   23242001
      Alice Springs        6   23232001
      Gingin               5   22232001
      Canberra             7   23241000
      Hobart               6   23331000    

Estimated Antarctic Regional K Indices 18 Sep :
      Macquarie Island    15   24354000
      Casey               10   34332001
      Mawson              16   33432015

Observed Regional daily pc3 Indices 18 Sep : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin              21   (Quiet to unsettled)
      Canberra             9   (Quiet)
      Hobart              21   (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 18 Sep : A 
           Fredericksburg        10
           Planetary             11                         

Observed AFr/Ap Indices 17 Sep :  A   K
           Fredericksburg        19
           Planetary             21   2303 3355     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
19 Sep     8    Quiet to Unsettled
20 Sep     7    Quiet
21 Sep    15    Unsettled to Active. Chance of minor storm period.

COMMENT: On UT day 18 September, geomagnetic conditions in the 
Australian region were quiet to active. In the Antarctic region, 
quiet to minor storm levels were observed. Geomagnetic conditions 
are expected to be mostly quiet on 19-20 September. A CME may 
arrive on 21 September causing active to minor storm levels.

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

PCA Event : No event.

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

COMMENT: Mild to moderate MUF depressions were observed on 18 
September. Normal conditions are expected on 19-21 September.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
18 Sep    11

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available.
   Niue Island Region:
      No data available.
   Northern Australian Region:
      Depressed by 15% during local day.
      Depressed to 25% during local night.
   Southern Australian Region:
      Depressed by 20% during local day.
      Depressed by 25% during local night.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Depressed 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
19 Sep    15    Near predicted monthly values
20 Sep    15    Near predicted monthly values
21 Sep    15    Near predicted monthly values

COMMENT: MUFs in the Australian region on UT day 18 September 
were mostly near predicted monthly values to 25% depressed. Night 
spread F was observed at Canberra. MUFs in the Australian region 
on 19-21 September are expected to be near predicted monthly 
values to mildly depressed.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 17 Sep
       Daily Proton Fluence >1 MeV:   2.3e+05
       Daily Proton Fluence >10 MeV:  4.7e+04
       Daily Electron Fluence >2 MeV: 2.90e+06
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A5.2

DSCOVR Satellite Solar Wind Day Averaged Data for 17 Sep
Speed: 361 km/sec  Density:   11.0 p/cc  Temp:    64100 K  Bz:  -4 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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