[Ips-dsgr] ASWFC Daily Report - 12 September 25 issued 2330 UT on 12 Sep 2025 [SEC=OFFICIAL]

Australian Space Weather Forecasting Centre aswfc at bom.gov.au
Sat Sep 13 09:30:50 AEST 2025


SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/12 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 12 SEPTEMBER AND FORECAST FOR 13 SEPTEMBER - 15 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 12 Sep:  R0

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 12 Sep: 114/65


1B. SOLAR FORECAST
             13 Sep             14 Sep          15 Sep
Activity     R0, chance R1      R0, chance R1   R0, chance R1
Fadeouts     Possible           Possible        Possible
10.7cm/SSN   115/66             120/72          115/66

COMMENT: Solar activity on UT day 12-Sep was R0, with no significant 
solar flares. There are currently three numbered sunspot regions 
on the solar disk, however all regions are stable. Solar activity 
is expected to be R0 with a chance for R1 over 13-15 Sep. 

S0 solar radiation storm conditions were observed on UT day 12-Sep. 
S0 solar radiation storm conditions are expected over 13-15 Sep.
 
A large filament erupted from 1439 UT and was associated with 
a large CME, however this originated on the far side of the Sun 
and is not expected to be Earth directed. No other CMEs were 
observed on UT day 12-Sep. 

The solar wind environment on UT day 12-Sep was near background
 conditions. The solar wind speed ranged from 359 to 439 km/s. 
The peak total interlanetary field strength (IMF, Bt) was 7 nT 
and the north-south IMF component range (Bz) was +5 to -5 nT. 
The solar wind is expected to remain steady on UT day 13-Sep but 
become enhanced over 14-15 Sep due to a large northern hemisphere 
coronal hole.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 12 Sep: G0

Estimated Indices 12 Sep : A   K           
   Australian Region       5   12221221
      Cocos Island         4   12211120
      Darwin               6   12311222
      Townsville           6   11321222
      Learmonth            5   11212221
      Alice Springs        5   12221221
      Gingin               5   12211221
      Canberra             5   12221221
      Kennaook Cape Grim   7   11331221
      Hobart               7   12331221    

Estimated Antarctic Regional K Indices 12 Sep :
      Macquarie Island    10   02343310
      Casey                8   23321221
      Mawson              16   24322344

Observed Regional daily pc3 Indices 12 Sep : 
      Darwin               0   (Quiet)
      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 12 Sep : A 
           Fredericksburg        10
           Planetary              9                         

Observed AFr/Ap Indices 11 Sep :  A   K
           Fredericksburg        10
           Planetary             10   4332 2212     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
13 Sep     5    G0
14 Sep    13    G0-G1
15 Sep    18    G1-G2

COMMENT: ASWFC Geomagnetic Warning 68 was issued on 12 September 
and is current for 14-16 Sep. G0 geomagnetic conditions were 
observed in the Australian and Antarctic regions on UT day 12-Sep. 
G0 geomagnetic conditions are expected on UT day 13-Sep. Mostly 
G0 geomagnetic conditions are expected on UT day 14-Sep, although 
the coronal hole is expected to connect with Earth by late in 
the day which may cause periods of G1. G1-G2 geomagnetic conditions 
are possible on 15-Sep due to continued coronal hole influence.

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

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
13 Sep      Normal         Normal         Normal
14 Sep      Normal         Normal-fair    Fair-normal
15 Sep      Normal-fair    Normal-fair    Fair

COMMENT: HF radio propagation conditions on UT day 12-Sep were 
mostly normal to mildly degraded, especially in the northern 
hemisphere. HF radio propagation conditions are expected to be 
normal on 13-Sep, trending to degraded over 14-15 Sep due to 
the onset of a coronal hole.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
12 Sep    86

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

Monthly T index:
Month  T index
Aug      96
Sep      92
Oct      90

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
13 Sep    90    Near predicted monthly values
14 Sep    90    Near predicted monthly values
15 Sep    80    Near predicted monthly values to 10-20% depressed

COMMENT: ASWFC Preliminary HF Communications Warning 83 was issued 
on 12 September and is current for 15-16 Sep. Maximum usable 
frequencies (MUFs) in the Australian region on UT day 12-Sep 
were near predicted values. MUFs are expected to be near predicted 
values over 13-14 Sep but may begin to depress by 15-Sep due 
to anticipated geomagnetic activity from a coronal hole.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 11 Sep
       Daily Proton Fluence >1 MeV:   3.9E+04
       Daily Proton Fluence >10 MeV:  1.6E+04
       Daily Electron Fluence >2 MeV: 1.60E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: B6.1

DSCOVR Satellite Solar Wind Day Averaged Data for 11 Sep
Speed: 428 km/sec  Density:    2.7 p/cc  Temp:    48900 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



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