[Ips-dhfpr] ASWFC Daily HF Prop Report - 21 July 25 issued 2332 UT on 21 Jul 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

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

1. SUMMARY (21 JULY) 
Date   T index  Conditions    
21 Jul    88    Fair-normal    

Flares: none.

MUFs:
   Cocos Island Region:
      Enhanced by 30% during local day.
      Near predicted monthly values during local night.
      Depressed by 20% after local dawn.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
      Depressed by 15% after local dawn.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Jun      79
Jul      104
Aug      102


2. FORECAST (22 JULY - 24 JULY)
Date   T index  Conditions       MUFs                              
22 Jul    90    Normal-fair      Depressed 10 to 15%/near predicted 
                                 monthly values
23 Jul    80    Fair             Depressed 10 to 20%/near predicted 
                                 monthly values    
24 Jul    70    Fair-normal      Depressed 10 to 20%/near predicted 
                                 monthly values   

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 21-Jul were 20% depressed to near predicted 
monthly values. Spread F was observed during local night hours 
at Hobart. Sporadic E was observed at Hobart and Niue. MUFs are 
expected to be generally 10-20% depressed to near predicted monthly 
values over 22-24 Jul, with degraded HF conditions during local 
night hours during 23-24 Jul due to expected mild geomagnetic 
activity induced by a coronal hole wind stream..

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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