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

[Regional Warning Centre]

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

1. SUMMARY (18 SEPTEMBER) 
Date   T index  Conditions    
18 Sep   102    Fair           

Flares: none.

MUFs:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Niue Island Region:
      Depressed by 15% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Mostly near predicted monthly values.
   Southern Australian Region:
      Mostly 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
Aug      115
Sep      96
Oct      93


2. FORECAST (19 SEPTEMBER - 21 SEPTEMBER)
Date   T index  Conditions       MUFs                              
19 Sep    90    Fair             Near predicted monthly values/depressed 
                                 15 to 25%
20 Sep    80    Normal-fair      Depressed 15 to 25%/near predicted 
                                 monthly values    
21 Sep    90    Normal           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 18-Sep were 
mostly near predicted values in the Australian region. Sporadic-E 
was observed at Norfolk Island and in Brisbane during local night/ 
dawn hours. Spread F was observed in Hobart and Perth during 
local night hours. MUF depressions of 15-25% are expected over 
19-21 Sep due to geomagnetic activity that was observed late 
in UT day 18-Sep. Degraded conditions are likely at high and 
middle latitudes during local night hours.

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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