[Ips-dhfpr] ASWFC Daily HF Prop Report - 17 December 25 issued 2330 UT on 17 Dec 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

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

1. SUMMARY (17 DECEMBER) 
Date   T index  Conditions    
17 Dec    82    Normal         

Flares: none.

MUFs:
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Nov      103
Dec      89
Jan      89


2. FORECAST (18 DECEMBER - 20 DECEMBER)
Date   T index  Conditions       MUFs                              
18 Dec    60    Fair             Depressed 15 to 20%/near predicted 
                                 monthly values
19 Dec    75    Fair-normal      Depressed 10 to 15%/near predicted 
                                 monthly values    
20 Dec    90    Normal           Near predicted monthly values   

COMMENT: ASWFC HF Communications Warning 123 was issued on 17 
December and is current for 18 Dec only. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 17-Dec were near predicted 
values. Sporadic E was observed during the local day. MUFs are 
expected to be 15-20% depressed to near predicted values for 
18-Dec, 10-15% depressed on 19-Dec and near predicted monthly 
values on 20-Dec. Mildly degraded HF conditions are possible 
during local night hours 18-19 Dec.

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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