[Ips-dsgr] ASWFC Daily Report - 17 June 26 issued 2330 UT on 17 Jun 2026 [SEC=OFFICIAL]

Thu Jun 18 09:30:49 AEST 2026

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/17 JUNE 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 17 JUNE AND FORECAST FOR 18 JUNE - 20 JUNE
STATUS INDICATORS SOL:** YELLOW **   MAG:GREEN     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 17 Jun:  R0
Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Jun: 111/62

1B. SOLAR FORECAST
             18 Jun             19 Jun             20 Jun
Activity     R0                 R0                 R0, chance of R1
Fadeouts     None expected      None expected      Possible
10.7cm/SSN   112/63             114/65             118/70

COMMENT: Solar flare activity on UT day 17-Jun was at the R0 
level, with no significant flaring activity. There are currently 
three numbered active regions (ARs) and on unnumbered AR visible 
on the solar disk. AR 4470 (N07E59, beta) showed some spot development, 
but was otherwise unremarkable. The other numbered ARs are in 
decay. An unnumbered AR has developed on the disk at around N13E25 
with beta magnetic complexity. Solar flare activity is expected 
to be at the R0 level over 18-20 Jun, with a chance of R1 on 
20-Jun due to ARs expected to rotate over the eastern limb. S0 
solar radiation storm conditions were observed on UT day 17-Jun. 
S0 solar radiation storm conditions are expected over 18-20 Jun. 
No Earth-directed coronal mass ejections (CMEs) were observed 
on 17-Jun. A slow, north directed CME visible from 16/2000UT 
in SOHO and STEREO-A imagery has been further analysed and presents 
the chance of a glancing impact on 21-Jun. However, this is not 
expected to produce a significant space weather event. The solar 
wind speed on UT day 17-Jun increased, mostly ranging between 
395 to 520 km/s and is currently near 440 km/s. The peak total 
interplanetary magnetic field strength (IMF, Bt) was 12 nT and 
the north-south IMF component (Bz) range was -7 to +11 nT. The 
solar wind speed is expected to remain around current levels 
over 18-Jun, a slight increase is possible over 19-20 Jun due 
to a small coronal hole approaching a geoeffective location.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 17 Jun: G0

Estimated Indices 17 Jun : A   K           
   Australian Region       4   12222100
      Cocos Island         3   12222000
      Darwin               4   22222100
      Townsville           5   22222101
      Learmonth            4   22222100
      Alice Springs        4   22222100
      Gingin               3   11222100
      Canberra             4   12222100
      Kennaook Cape Grim   4   11232100
      Hobart               5   12232100    

Estimated Antarctic Regional K Indices 17 Jun :
      Macquarie Island     5   00043100
      Casey                5   23222100
      Mawson               8   22223311

Observed Regional daily pc3 Indices 17 Jun : 
      Darwin              NA
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Hobart               0   (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 17 Jun : A 
           Fredericksburg         5
           Planetary              6                         

Observed AFr/Ap Indices 16 Jun :  A   K
           Fredericksburg         6
           Planetary              6   2111 2221     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
18 Jun     4    G0
19 Jun     6    G0
20 Jun     5    G0

COMMENT: G0 geomagnetic conditions were observed in the Australian 
and Antarctic regions and at the planetary level on UT day 17-Jun. 
G0 planetary geomagnetic conditions are expected over 18-20 Jun.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
17 Jun      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
18 Jun      Normal         Normal         Normal
19 Jun      Normal         Normal         Normal
20 Jun      Normal         Normal         Normal

COMMENT: High frequency propagation conditions were mostly normal 
on UT day 17-Jun with some degradations at all latitudes from 
1700UT onwards. HF propagation conditions are expected to be 
mostly normal over 18-20 Jun.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
17 Jun    79

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available during local day.
      No data available during local night.
   Niue Island Region:
      Enhanced by 25% during local day.
      Depressed by 25% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

Monthly T index:
Month  T index
May      67
Jun      68
Jul      65

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
18 Jun    80    Near predicted monthly values
19 Jun    80    Near predicted monthly values
20 Jun    80    Near predicted monthly values

COMMENT: Maximum Usable Frequencies (MUFs) in the Australian 
region were mostly near predicted monthly values on 16-Jun, with 
15% depressions observed in the northern Australian region during 
local night hours. Spread F was observed at Hobart and Darwin 
during local night hours. MUFs are expected to be near predicted 
monthly values over 18-20 Jun.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 16 Jun
       Daily Proton Fluence >1 MeV:   7.8E+05
       Daily Proton Fluence >10 MeV:  1.7E+04
       Daily Electron Fluence >2 MeV: 8.10E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 9%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B4.8

DSCOVR Satellite Solar Wind Day Averaged Data for 16 Jun
Speed: 415 km/sec  Density:    5.7 p/cc  Temp:    84700 K  Bz:   2 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