[Ips-dhfpr] ASWFC Daily HF Prop Report - 18 April 26 issued 2330 UT on 18 Apr 2026 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/18 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (18 APRIL) 
Date   T index  Conditions    
18 Apr    90    Fair-normal    

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.
      Enhanced by 30% during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Mar      92
Apr      83
May      81


2. FORECAST (19 APRIL - 21 APRIL)
Date   T index  Conditions       MUFs                              
19 Apr    55    Fair             Depressed 10 to 20%/near predicted 
                                 monthly values
20 Apr    65    Fair-normal      Depressed 10 to 15%/near predicted 
                                 monthly values    
21 Apr    75    Normal-fair      Near predicted monthly values   

COMMENT: ASWFC Preliminary HF Communications Warning 36 was issued 
on 16 April and is current for 18-20 Apr. Maximum Usable Frequencies 
(MUFs) in the Australian region were largely near predicted values 
on 18-Apr, with some enhancements seen at Niue Island and the 
Southern Australian region. Spread-F was observed in Hobart and 
Niue Island, with a scintillation event also reported between 
18/0811-0830UT at Niue Island. MUFs are expected to become depressed 
by 10-20% on 19-20 Apr due to ongoing geomagnetic activity, before 
beginning to recover to near predicted monthly values on 21-Apr.

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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