[Ips-dhfpr] ASWFC Daily HF Prop Report - 29 July 23 issued 2330 UT on 29 Jul 2023 [SEC=OFFICIAL]

[Regional Warning Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/29 JULY 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (29 JULY) 
Date   T index  Conditions    
29 Jul   111    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M1.4    1624UT  possible   lower  South American/
                                    Atlantic

MUFs:
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values over the UT day.
      Proton event in progress, increased absorption observed.

PCA Event : 10MeV Proton/PCA Event Began 29 07 2023 0035UT and is in progress

Monthly T index:
Month  T index
Jun      98
Jul      91
Aug      88


2. FORECAST (30 JULY - 01 AUGUST)
Date   T index  Conditions       MUFs                              
30 Jul   105    Normal-fair      Near predicted monthly values
31 Jul   105    Normal-fair      Near predicted monthly values    
01 Aug    80    Normal-fair      Near predicted monthly values 
                                 to 15% depressed   

COMMENT: ASWFC SWF HF Communications Warning 72 was issued on 
29 July and is current for 28-30 Jul. Maximum usable frequencies 
(MUFs) on UT day 29-Jul were mostly near predicted values. Spread-F 
was observed at Canberra, Hobart and Perth during local night 
hours. Sporadic-E was observed at Brisbane during local dawn. 
MUFs are expected to remain near predicted values over 30-31 
Jul, then experience some mild depressions of 15-20% over 01-Aug 
due to expected geomagnetic activity from a CME first observed 
on 28-Jul. Polar cap absorption (PCA) began from 28/2350 UT and 
is currently in progress, causing degraded HF conditions, particularly 
in high latitudes. The PCA is expected to continue over 30-Jul. 
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