[Ips-dsgr] ASWFC Daily Report - 21 June 25 issued 2330 UT on 21 Jun 2025 [SEC=OFFICIAL]

Sun Jun 22 09:30:55 AEST 2025

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/21 JUNE 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 21 JUNE AND FORECAST FOR 22 JUNE - 24 JUNE
STATUS INDICATORS SOL:** YELLOW **   MAG:GREEN     ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 21 Jun:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 21 Jun: 120/72

1B. SOLAR FORECAST
             22 Jun             23 Jun             24 Jun
Activity     R0-R1              R0-R1              R0-R1
Fadeouts     Possible           Possible           Possible
10.7cm/SSN   120/72             115/66             115/66

COMMENT: Solar activity on UT day 21-Jun was R0, with no solar 
flares. There are currently five numbered sunspots on the solar 
disk. AR4114 (N16W67, beta) has decayed into a standard bipolar 
configuration. Both AR4117 (S14E25, beta) and AR4118 (S13E35, 
beta) have grown in the past 24 hours and developed trailer spots. 
Solar activity is expected to be R0-R1 over 22-24 Jun.

 No Earth-directed CMEs were observed in available imagery. 

S0 solar radiation storm conditions were observed on UT day 21-Jun. 
S0 solar radiation storm conditions are expected over 22-24 Jun. 

The solar wind was mildly enhanced on UT day 21-Jun, likely due 
to coronal hole effects. The solar wind speed ranged from 430 to 
560 km/s. The peak total interplanetary field strength (IMF, Bt) was 10 nT 
and the north-south IMF component range (Bz) was +8 to -7 nT 
with some brief periods of southward Bz. The solar wind environment 
is likely to fluctuate over 22-24 Jun due to intermittent coronal 
hole connections.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 21 Jun: G0

Estimated Indices 21 Jun : A   K           
   Australian Region       6   12113212
      Cocos Island         4   12112201
      Darwin               7   22213212
      Townsville           7   22213212
      Learmonth            8   23213212
      Alice Springs        5   12113202
      Gingin               7   22113312
      Canberra             5   12113202
      Kennaook Cape Grim   6   12113212
      Hobart               7   12114202    

Estimated Antarctic Regional K Indices 21 Jun :
      Macquarie Island     8   11014411
      Casey               10   23323222
      Mawson              15   34223342

Observed Regional daily pc3 Indices 21 Jun : 
      Darwin               2   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               2   (Quiet)
      Canberra             5   (Quiet)
      Hobart               8   (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 21 Jun : A 
           Fredericksburg        10
           Planetary             11                         

Observed AFr/Ap Indices 20 Jun :  A   K
           Fredericksburg         8
           Planetary             11   1233 2321      

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
22 Jun     8    G0
23 Jun    10    G0
24 Jun    12    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
and Antarctic regions on UT day 21-Jun. G0 geomagnetic conditions 
are generally expected over 22-24 Jun.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
21 Jun      Fair           Normal-fair    Normal-fair    

PCA Event : No event.

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

COMMENT: HF radio propagation conditions on UT day 21-Jun were 
degraded during local night hours, but generally normal during 
local daylight hours. HF radio propagation conditions are expected 
to be degraded to mildly degraded during local night hours over 
22-24 Jun, but conditions may be normal during daylight hours.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
21 Jun    81

Observed Australian Regional MUFs
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 35% during local night.
      Depressed by 20% after local dawn.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
      Depressed by 20% after local dawn.
   Southern Australian Region:
      Depressed by 15% during local day.
      Depressed by 15% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.

Monthly T index:
Month  T index
May      94
Jun      109
Jul      107

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
22 Jun    85    Near predicted monthly values to 10-20% depressed
23 Jun    85    Near predicted monthly values to 10-20% depressed
24 Jun    85    Near predicted monthly values to 10-20% depressed

COMMENT: ASWFC HF Communications Warning 67 was issued on 21 
June and is current for 22-24 Jun. Maximum usable frequencies 
(MUFs) in the Australian region were 15-20% depressed on UT day 
21-Jun. Conditions were generally degraded in the northern Australian 
region and sporadic-E was common during local night hours. MUFs 
are expected to be similar over 22-24 Jun, being 10-20% depressed, 
especially during local night hours.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 20 Jun
       Daily Proton Fluence >1 MeV:   1.3E+05
       Daily Proton Fluence >10 MeV:  1.6E+04
       Daily Electron Fluence >2 MeV: 3.40E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B6.6

DSCOVR Satellite Solar Wind Day Averaged Data for 20 Jun
Speed: 533 km/sec  Density:    1.3 p/cc  Temp:   235000 K  Bz:   1 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
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Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au