[Ips-dsgr] SWS Daily Report - 16 April 21 issued 2330 UT on 16 Apr 2021

Regional Warning Centre rwc at ips.gov.au
Sat Apr 17 09:30:08 EST 2021


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/16 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 16 APRIL AND FORECAST FOR 17 APRIL - 19 APRIL
STATUS INDICATORS SOL:GREEN   MAG:** YELLOW **     ION: GREEN
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 16 Apr:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Apr:  77/16


1B. SOLAR FORECAST
             17 Apr             18 Apr             19 Apr
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              78/17

COMMENT: Solar activity was very low on UT day 16 April. There 
are currently three numbered regions on the visible disk, AR 
2814, AR 2815, and AR 2816. Solar activity is expected to be 
very low to low for the next three days, 17-19 April. No Earth 
directed CMEs were observed in the available images up to 16/1548 
UT. On 16 April, the solar wind speed was initially near 380 
km/s. Near 16/1200 UT it reached 480 km/s due to anticipated 
coronal hole effects. The total IMF (Bt) was near 5 nT at the 
beginning of the UT day, then increased after 16/0200 UT to 7-12 
nT while Bz was mostly negative during the UT day and reached 
-10 nT after 16/1600 UT. The solar wind speed is expected to 
remain enhanced over the next three UT days, 17-19 April, due 
to coronal hole effects.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 16 Apr: Quiet to Active

Estimated Indices 16 Apr : A   K           
   Australian Region      13   23233243
      Cocos Island        11   22222343
      Darwin              11   23223242
      Townsville          15   33333243
      Learmonth           20   33333354
      Alice Springs       11   22233242
      Gingin               6   022231--
      Canberra            12   22233342
      Hobart              14   23233343    

Estimated Antarctic Regional K Indices 16 Apr :
      Macquarie Island    18   12334353
      Casey               19   24522343
      Mawson              51   23333486

Observed Regional daily pc3 Indices 16 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               3   (Quiet)
      Canberra             4   (Quiet)
      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 16 Apr : A 
           Fredericksburg        16
           Planetary             20                         

Observed AFr/Ap Indices 15 Apr :  A   K
           Fredericksburg        11
           Planetary             10   2341 2212     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
17 Apr    20    Active
18 Apr    15    Unsettled to Active
19 Apr    10    Quiet to Unsettled

COMMENT: SWS Geomagnetic Warning 14 was issued on 16 April and 
is current for 17-18 Apr. Mostly quiet to active geomagnetic 
conditions were observed in the Australian region on UT day 16 
April. Quiet to storm levels were observed in the Antarctic region. 
The observed increase in geomagnetic activity is due to coronal 
hole effects. On 17 April and 18 April, geomagnetic activity 
is expected to reach active levels with possible isolated minor 
storm periods on 17 April.

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

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
17 Apr      Normal-fair    Normal-fair    Fair
18 Apr      Normal         Normal-fair    Normal-fair
19 Apr      Normal         Normal         Normal-fair

COMMENT: Mildly degraded conditions may be observed on 17-18 
April.

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


Date   T index
16 Apr    14

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 by 15% during local night.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Depressed by 25% after local dawn.
   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
17 Apr     0    Near predicted monthly values/depressed 10 to 
                30%
18 Apr     0    Near predicted monthly values/depressed 10 to 
                30%
19 Apr     4    Near predicted monthly values

COMMENT: SWS HF Communications Warning 11 was issued on 16 April 
and is current for 17-18 Apr. MUFs over the Australian regions 
were mostly near predicted monthly levels on UT day 16 April; 
mild depressions were observed in the Northern Australian region 
and moderate depressions were seen in the Southern Australian 
region after local dawn. Mild to moderate MUFs depressions are 
likely for 17-18 April due to the observed increase in geomagnetic 
activity.

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

GOES satellite data for 15 Apr
       Daily Proton Fluence >1 MeV:   7.3E+04
       Daily Proton Fluence >10 MeV:  4.2E+04
       Daily Electron Fluence >2 MeV: 1.30E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A4.7

DSCOVR Satellite Solar Wind Day Averaged Data for 15 Apr
Speed: 366 km/sec  Density:   11.7 p/cc  Temp:    38600 K  Bz:   3 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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