[Ips-dsgr] SWS Daily Report - 23 April 21 issued 2341 UT on 23 Apr 2021

Sat Apr 24 09:41:34 EST 2021

SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/23 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 23 APRIL AND FORECAST FOR 24 APRIL - 26 APRIL
STATUS INDICATORS SOL:GREEN   MAG:** RED **     ION: ** YELLOW **
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1A. SOLAR SUMMARY
Activity 23 Apr:  Low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 23 Apr:  77/16

1B. SOLAR FORECAST
             24 Apr             25 Apr             26 Apr
Activity     Low                Low                Low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    77/16              77/16              77/16

COMMENT: Solar activity was low on UT day 23 April. There are 
currently two numbered regions on the visible disk, AR2816 and 
AR2818. Region 2817 produced several B-class and C-class flares 
before rotating off the visible disk. An impulsive CME was observed 
around 23/05 UT possibly associated with the flaring activity 
from region 2817, unlikely to have an earth directed component. 
A filament eruption was observed in SDO images after 23/19 UT. 
Further analysis about this event is in progress. No other earthward 
directed CMEs were observed in the available images. Solar activity 
is expected to be low for the next three UT days, 24-26 April 
with C-class flares possible during this period and a slight 
chance of an isolated M-class event. On UT day 23 April, the 
solar wind parameters showed an upward trend indicating the arrival 
the of the CIR leading coronal hole. The solar wind speed increased 
to 470 km/s while Bt and Bz peaked at 11 nT and -10 nT, respectively. 
The solar wind speed is expected to be elevated over the next 
three UT days,24-26 April due to joint effect of 22 April CME 
along with the coronal hole effects.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 23 Apr: Quiet to active

Estimated Indices 23 Apr : A   K           
   Australian Region       9   12121324
      Cocos Island         8   12111324
      Darwin               9   22111324
      Townsville           9   22121324
      Learmonth           12   12121335
      Alice Springs        8   12111324
      Gingin              14   22211435
      Canberra             9   12221324
      Hobart               9   12221314    

Estimated Antarctic Regional K Indices 23 Apr :
      Macquarie Island     9   12331322
      Casey               13   33321324
      Mawson              52   54332477

Observed Regional daily pc3 Indices 23 Apr : 
      Darwin               0   (Quiet)
      Townsville           2   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             9   (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 23 Apr : A 
           Fredericksburg        11
           Planetary             13                         

Observed AFr/Ap Indices 22 Apr :  A   K
           Fredericksburg         4
           Planetary              5   1221 2112     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
24 Apr    15    Quiet to Active
25 Apr    30    Active to Minor Storm with a chance of an isolated 
                Major storm period.
26 Apr    20    Active with a chance of minor storm periods.

COMMENT: SWS Geomagnetic Warning 15 was issued on 23 April and 
is current for 25 Apr only. Quiet to active geomagnetic conditions 
were observed in the Australian region on UT day 23 April. Quiet 
to storm levels were observed in the Antarctic region. Geomagnetic 
activity is expected to be at quiet to unsettled levels with 
possible active periods on UT day 24 April due to coronal hole 
effects. Geomagnetic activity is expected to increase to minor 
storm levels on 25-26 April with a chance of an isolated major 
storm period on 25 April due coupled effects of 22 April CME 
an Coronal hole effects .

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

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
24 Apr      Normal-fair    Fair-normal    Fair-normal
25 Apr      Normal-fair    Fair-normal    Fair
26 Apr      Normal-fair    Fair-normal    Fair

COMMENT: Moderate degradation in HF propagation conditions are 
possible on UT days 24-26 April.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
23 Apr    14

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available.
   Niue Island Region:
      No data available.
   Northern Australian Region:
      Near predicted monthly values.
   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
24 Apr     5    Near predicted monthly values/depressed 10 to 
                15%
25 Apr    -5    Depressed 10 to 30%/near predicted monthly values
26 Apr    -5    Near predicted monthly values/depressed 10 to 
                30%

COMMENT: MUFs in the Australian region on UT day 24 April were 
mostly near predicted monthly values. Minor to moderate MUF depressions 
are possible on UT days 24-26 April due to expected rise in geomagnetic 
activity.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 22 Apr
       Daily Proton Fluence >1 MeV:   8.3E+04
       Daily Proton Fluence >10 MeV:  4.3E+04
       Daily Electron Fluence >2 MeV: 6.90E+08   (high fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability:26%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B2.3

DSCOVR Satellite Solar Wind Day Averaged Data for 22 Apr
Speed: 423 km/sec  Density:    5.5 p/cc  Temp:    85400 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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