[Ips-dhfpr] ASWFC Daily HF Prop Report - 21 May 23 issued 2330 UT on 21 May 2023 [SEC=OFFICIAL]

[Regional Warning Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/21 MAY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (21 MAY) 
Date   T index  Conditions    
21 May    97    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M5.2 20/2306UT  possible   lower  West Pacific
  M1.4    0223UT  possible   lower  E. Asia/Aust.
  M2.6    1604UT  possible   lower  South American/
                                    Atlantic

MUFs:
   Cocos Island Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Apr      120
May      87
Jun      88


2. FORECAST (22 MAY - 24 MAY)
Date   T index  Conditions       MUFs                              
22 May    85    Fair             Near predicted monthly values 
                                 to 15% depressed
23 May    95    Normal-fair      Near predicted monthly values    
24 May    80    Fair             Near predicted monthly values 
                                 to 15% depressed   

COMMENT: ASWFC SWF HF Communications Warning 47 was issued on 
19 May and is current for 20-22 May. ASWFC HF Communications 
Warning 48 was issued on 21 May and is current for 22-24 May. 
Maximum usable frequencies (MUFs) on UT day 21-May were near 
predicted monthly values in the Australian region. Spread-F, 
range-spread and sporadic-E were observed at most sites during 
local night hours. Degraded conditions were observed particularly 
at low-latitude sites during local night. MUFs are expected to 
be near predicted monthly values to 15% depressed over 22-24 
May. 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