[Ips-dhfpr] ASWFC Daily HF Prop Report - 20 April 25 issued 2333 UT on 20 Apr 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/20 APRIL 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (20 APRIL) 
Date   T index  Conditions    
20 Apr   103    Fair-normal    

Flares    Max     Fadeout    Freq.  Sectors
  M1.0    1211UT  possible   lower  European

MUFs:
   Cocos Island Region:
      Enhanced by 35% during local day.
      Near predicted monthly values during local night.
   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.
      Enhanced by 20% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Hobart MUFs depressed 15-30%.
      Depressed by 15-30% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 30% over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Mar      126
Apr      115
May      113


2. FORECAST (21 APRIL - 23 APRIL)
Date   T index  Conditions       MUFs                              
21 Apr   115    Normal-fair      Near predicted monthly values
22 Apr    95    Normal-fair      10 to 15% below predicted monthly 
                                 values    
23 Apr    85    Normal-fair      10 to 20% below predicted monthly 
                                 values   

COMMENT: Maximum usable frequencies (MUFs) in the Australian 
region on UT day 20-Apr were variable. Most southern region sites 
during the local day were near predicted monthly values becoming 
15-30% depressed during the local night hours. Hobart MUFs were 
initially 30% depressed, slowly recovering during the local day, 
then becoming depressed again during local night hours. Northern 
Australian region sites were near predicted monthly values to 
20% enhanced. Spread F was observed during local night hours 
at Hobart and Canberra. MUFs for 21-Apr are expected to be generally 
near predicted monthly values. Southern Australian regional MUFs 
are expected to become depressed 10-20% at times over 22-23 Apr 
due to anticipated 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