[Ips-dhfpr] ASWFC Daily HF Prop Report - 17 May 25 issued 2331 UT on 17 May 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/17 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (17 MAY) 
Date   T index  Conditions    
17 May    92    Fair-poor      

Flares: none.

MUFs:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   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 35% during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 40% over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Apr      123
May      113
Jun      111


2. FORECAST (18 MAY - 20 MAY)
Date   T index  Conditions       MUFs                              
18 May    90    Fair             Depressed 15%/near predicted 
                                 monthly values
19 May    90    Normal-fair      Depressed 15%/near predicted 
                                 monthly values    
20 May   100    Normal-fair      Near predicted monthly values   

COMMENT: ASWFC HF Communications Warning 48 was issued on 16 
May and is current for 17-19 May. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 17-May were near predicted 
monthly values in the southern Australian region, with depressions 
of 35% observed in the northern Australian region during local 
night. Spread F was observed at Hobart and Brisbane during local 
night hours. Sporadic E was also observed at Brisbane. MUFs are 
expected to be near predicted monthly values to 15% depressed 
over 18-19 May. A recovery towards monthly predicted values is 
expected on 20-May. 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