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

[Australian Space Weather Forecasting Centre]

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

1. SUMMARY (21 APRIL) 
Date   T index  Conditions    
21 Apr   105    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M1.9    1837UT  possible   lower  East Pacific/
                                    North American

MUFs:
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   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
Mar      126
Apr      115
May      113


2. FORECAST (22 APRIL - 24 APRIL)
Date   T index  Conditions       MUFs                              
22 Apr   100    Fair             10 to 20% below predicted monthly 
                                 values
23 Apr    90    Fair             15 to 25% below predicted monthly 
                                 values    
24 Apr    85    Fair             15 to 25% below predicted monthly 
                                 values   

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 21-Apr were near predicted values to 20% depressed. 
Sporadic-E was observed in the Cocos Islands during local night 
hours. MUFs are expected to be depressed 10-25% over 22-24 Apr 
due to coronal hole activity. Spread-F is expected over local 
night hours.

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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