[Ips-dhfpr] ASWFC Daily HF Prop Report - 21 September 25 issued 2330 UT on 21 Sep 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/21 SEPTEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (21 SEPTEMBER) 
Date   T index  Conditions    
21 Sep   114    Normal         

Flares: none.

MUFs:
   Cocos Island Region:
      No data available during local day.
      No data available during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 25% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Southern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 20% during local night.
      Enhanced by 25% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

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


2. FORECAST (22 SEPTEMBER - 24 SEPTEMBER)
Date   T index  Conditions       MUFs                              
22 Sep   110    Normal-fair      Near predicted monthly values
23 Sep   100    Normal-fair      Near predicted monthly values    
24 Sep   100    Normal           Near predicted monthly values   

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 21-Sep were near predicted values to 25% enhanced. 
Spread F was observed in Perth over local night. On 22-Sep HF 
conditions are likely to be enhanced by 15% during the local 
day then mildly degraded conditions may be experienced during 
local night hours for the southern Australian region due to an 
anticipated mild increase in geomagnetic activity from a coronal 
hole wind stream. MUFs are expected to be near predicted values 
over 22-24 Sep. Mildly degraded conditions are expected during 
local night hours on 23-Sep. 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