[Ips-dhfpr] ASWFC Daily HF Prop Report - 21 May 25 issued 2331 UT on 21 May 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

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

1. SUMMARY (21 MAY) 
Date   T index  Conditions    
21 May    96    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M1.2    0008UT  possible   lower  West Pacific

MUFs:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Southern Australian Region:
      Mostly near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

PCA Event : No event.

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


2. FORECAST (22 MAY - 24 MAY)
Date   T index  Conditions       MUFs                              
22 May    90    Normal           Depressed 15%/near predicted 
                                 monthly values
23 May    90    Normal           Depressed 15%/near predicted 
                                 monthly values    
24 May    90    Normal           Depressed 15%/near predicted 
                                 monthly values   

COMMENT: ASWFC SWF HF Communications Warning 50 was issued on 
21 May and is current for 21-23 May. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 21-May were near predicted 
monthly values during local day with depressions of up to 30% 
observed in the northern Australian region. Spread F and sporadic 
E was observed at Hobart during local night hours and light sporadic 
E was observed at Brisbane. MUFs are expected to be near predicted 
monthly values to 15% depressed over 22-24 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