[Ips-dsgr] SWS Daily Report - 19 April 21 issued 2330 UT on 19 Apr 2021

Regional Warning Centre rwc at ips.gov.au
Tue Apr 20 09:30:08 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/19 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 19 APRIL AND FORECAST FOR 20 APRIL - 22 APRIL
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 19 Apr:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 19 Apr:  86/29


1B. SOLAR FORECAST
             20 Apr             21 Apr             22 Apr
Activity     Very low to low    Very low to low    Very low to low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    85/27              85/27              85/27

COMMENT: Solar activity was very low on UT day 19 April. There 
are currently three numbered regions on the visible disk, AR 
2815, AR 2816, and AR 2817. Solar activity is expected to be 
very low to low for the next three UT days, 20-22 April. No earthward 
directed CMEs were observed. On UT day 19 April, the solar wind 
speed varied mostly between 560 km/s and 660 km/s in response 
to the effects of the Southern polar coronal hole with extension 
into the low latitudes, the IMF (Bt) range was 3 to 7 nT and 
the north-south IMF (Bz) range was +6/-6 nT. The solar wind speed 
is expected to gradually decrease through UT day 20 April due 
to the waning of the coronal hole effects.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 19 Apr: Quiet to Active

Estimated Indices 19 Apr : A   K           
   Australian Region      12   23343222
      Cocos Island         8   22232222
      Darwin              10   23333122
      Townsville          13   23343223
      Learmonth           15   23343333
      Alice Springs       13   23343223
      Gingin              16   3234----
      Canberra            12   23343222
      Hobart              17   23453322    

Estimated Antarctic Regional K Indices 19 Apr :
      Macquarie Island    42   34675322
      Casey               20   44343243
      Mawson              55   56555366

Observed Regional daily pc3 Indices 19 Apr : 
      Darwin               0   (Quiet)
      Townsville           2   (Quiet)
      Learmonth            2   (Quiet)
      Alice Springs        4   (Quiet)
      Gingin              71   (Active)
      Canberra            60   (Unsettled)
      Melbourne           NA

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 19 Apr : A 
           Fredericksburg        11
           Planetary             14                         

Observed AFr/Ap Indices 18 Apr :  A   K
           Fredericksburg        13
           Planetary             16   3443 2233     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
20 Apr    10    Mostly quiet to unsettled, isolated active periods 
                possible
21 Apr     7    Quiet with the possibility of some unsettled 
                periods
22 Apr     5    Quiet

COMMENT: Mostly quiet to active geomagnetic conditions were observed 
in the Australian region on UT day 19 April. Quiet to storm levels 
were observed in the Antarctic region. The observed elevated 
geomagnetic activity is due to the coronal hole effects. On UT 
day 20 April, geomagnetic activity is expected to be mostly at 
quiet to unsettled levels with possible isolated active periods 
due to the continued coronal hole effects. Mostly quiet to unsettled 
conditions on 21 April and quiet conditions on 22 April are expected.

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

PCA Event : No event.

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

COMMENT: Mostly normal HF propagation conditions are expected. 
Periods of minor degradations may be observed on UT day 20 April 
at high latitudes.

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


Date   T index
19 Apr    25

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available during local day.
      No data available during local night.
   Niue Island Region:
      No data available during local day.
      No data available during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15% 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
Mar      9
Apr      19
May      23

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
20 Apr    20    Near predicted monthly values
21 Apr    22    Near predicted monthly values
22 Apr    22    Near predicted monthly values

COMMENT: MUFs over the Australian regions were mostly near predicted 
monthly levels on UT day 18 April. Mild enhancements were observed 
in the Northern Australian region during local night. Minor to 
mild MUFs depressions are possible on UT day 20 April due to 
some possible rise in geomagnetic activity.

-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 18 Apr
       Daily Proton Fluence >1 MeV:   5.0E+05
       Daily Proton Fluence >10 MeV:  4.2E+04
       Daily Electron Fluence >2 MeV: 3.50E+08   (moderate fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:20%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A7.4

DSCOVR Satellite Solar Wind Day Averaged Data for 18 Apr
Speed: 573 km/sec  Density:   10.4 p/cc  Temp:   455000 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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