[Ips-dhfpr] ASWFC Daily HF Prop Report - 18 December 23 issued 2330 UT on 18 Dec 2023 [SEC=OFFICIAL]

[Regional Warning Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/18 DECEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (18 DECEMBER) 
Date   T index  Conditions    
18 Dec    71    Fair-normal    

Flares: none.

MUFs:
   Cocos Island Region:
      Enhanced by 15-20%.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 55% during local night.
   Northern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values during local night.
      Depressed by 20% after local dawn.
   Southern Australian Region:
      Depressed by 30% during local day.
      Depressed by 20% during local night and after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Nov      114
Dec      100
Jan      98


2. FORECAST (19 DECEMBER - 21 DECEMBER)
Date   T index  Conditions       MUFs                              
19 Dec    50    Fair-normal      Depressed 15 to 20%/near predicted 
                                 monthly values
20 Dec   100    Normal           Near predicted monthly values    
21 Dec   100    Normal           Near predicted monthly values   

COMMENT: ASWFC HF Communications Warning 131 was issued on 18 
December and is current for 19 Dec only. Maximum usable frequencies 
(MUFs) were generally depressed 15-30% during the local day in 
the Australian region on UT day 18-Dec. Depressions of 20% have 
been observed after local dawn this morning due to recent geomagnetic 
activity. MUFs are generally expected to be 15-20% depressed 
for 19-Dec, then near predicted monthly values for 20-21 Dec. 
Isolated 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