[Ips-dhfpr] ASWFC Daily HF Prop Report - 20 September 25 issued 2330 UT on 20 Sep 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/20 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (20 SEPTEMBER) 
Date   T index  Conditions    
20 Sep   107    Normal         

Flares: none.

MUFs:
   Cocos Island Region:
      No data available.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 30% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15-50% during local night.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Enhanced by 25% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Enhanced by 15% over the UT day.

PCA Event : No event.

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


2. FORECAST (21 SEPTEMBER - 23 SEPTEMBER)
Date   T index  Conditions       MUFs                              
21 Sep   100    Normal           Near predicted monthly values
22 Sep   100    Normal-fair      Near predicted monthly values    
23 Sep   100    Fair-normal      Near predicted monthly values   

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 20-Sep were near predicted values to 50% enhanced, 
with enhancements of 50% observed at Darwin during local night 
hours. Other northern Australian region sites were enhanced by 
15% during the local night. MUFs are expected to be near predicted 
values over 21-23 Sep. Mildly degraded HF conditions may be experienced 
during local night hours for the southern Australian region during 
22-23 Sep, due to an anticipated mild increase in geomagnetic 
activity from a coronal hole wind stream. Isolated minor shortwave 
fadeouts are possible.

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For an explanation of some of the terms in this report, go to
https://www.sws.bom.gov.au, and follow links to Educational->
Glossary on Solar Terrestrial Terms.

Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au