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

[Regional Warning Centre]

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

1. SUMMARY (18 JULY) 
Date   T index  Conditions    
18 Jul   113    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M2.7 17/2255UT  possible   lower  East Pacific/
                                    North American
  M5.0 17/2334UT  possible   lower  West Pacific
  M5.7    0007UT  possible   lower  West Pacific
  M1.5    0657UT  possible   lower  Mid East/Indian
  M1.3    1948UT  possible   lower  East Pacific/
                                    North American
  M2.1    2027UT  possible   lower  East Pacific/
                                    North American

MUFs:
   Cocos Island Region:
      Enhanced by 20% during local day.
      Depressed by 20% during local night.
   Niue Island Region:
      Enhanced by 15% during local day.
      Enhanced by 30% during local night.
   Northern Australian Region:
      Enhanced by 20% during local day.
      Enhanced by 15% 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.
      Proton event in progress, increased absorption observed.

PCA Event : 10MeV Proton/PCA Event Began at 0145UT 18/07, Ended at 1425UT 18/07

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


2. FORECAST (19 JULY - 21 JULY)
Date   T index  Conditions       MUFs                              
19 Jul   110    Normal           Near to 15% above predicted 
                                 monthly values
20 Jul   100    Poor             Near predicted monthly values    
21 Jul   100    Poor             Near predicted monthly values   

COMMENT: ASWFC SWF HF Communications Warning 66 was issued on 
17 July and is current for 17-19 Jul. Maximum usable frequencies 
(MUFs) on UT day 18-Jul in the Australian region were generally 
near predicted monthly values with enhancements of up to 20% 
observed in the northern Australian region. Spread F was observed 
during local night hours in the southern Australian region. MUFs 
are expected to be near predicted monthly values to 15% enhanced 
in the northern Australian region on 19-Jul. Depressions are 
expected, particularly in the southern Australian region over 
20-21 Jul due to anticipated geomagnetic activity caused by impacts 
from CMEs first observed on 17-Jul and 18-Jul.

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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