[Ips-dhfpr] ASWFC Daily HF Prop Report - 17 September 23 issued 2334 UT on 17 Sep 2023 [SEC=OFFICIAL]

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SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/17 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (17 SEPTEMBER) 
Date   T index  Conditions    
17 Sep   102    Normal         

Flares: none.

MUFs:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Niue Island Region:
      Near predicted monthly values.
   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
Aug      115
Sep      96
Oct      93


2. FORECAST (18 SEPTEMBER - 20 SEPTEMBER)
Date   T index  Conditions       MUFs                              
18 Sep   100    Normal-fair      Near predicted monthly values
19 Sep    80    Fair-poor        Near predicted monthly values/depressed 
                                 15 to 25%    
20 Sep    70    Poor-fair        Depressed 15 to 25%/near predicted 
                                 monthly values   

COMMENT: ASWFC Preliminary HF Communications Warning 93 was issued 
on 17 September and is current for 19-20 Sep. ASWFC SWF HF Communications 
Warning 94 was issued on 17 September and is current for 17-19 
Sep. Maximum usable frequencies (MUFs) on UT day 17-Sep were 
near predicted monthly values. Brief ionospheric phase scintillation 
(<1deg.) was observed at Weipa at approximately 17/1000UT. Degraded 
HF conditions are expected during 19-20 Sep, particularly for 
the southern Australian region, due to expected geomagnetic storm 
activity from a recent CME associated with an solar filament 
eruption. The timing of any middle latitude ionospheric depression 
response will depend on the geomagnetic storm onset time and 
subsequent strength. Isolated minor fadeouts 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