[Ips-dhfpr] ASWFC Daily HF Prop Report - 31 May 25 issued 2330 UT on 31 May 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/31 MAY 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (31 MAY) 
Date   T index  Conditions    
31 May    84    Normal-fair    

Flares    Max     Fadeout    Freq.  Sectors
  M8.2    0005UT  probable   lower  West Pacific
  M2.4    0518UT  possible   lower  E. Asia/Aust.
  M4.5    0818UT  possible   lower  Mid East/Indian
  M2.9    1549UT  possible   lower  South American/
                                    Atlantic

MUFs:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Niue Island Region:
      No data available during local day.
      No data available during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.
      Proton event in progress, increased absorption observed.

PCA Event : 10MeV Proton/PCA Event Began 31 05 2025 1700UT and is in progress

Monthly T index:
Month  T index
Apr      123
May      113
Jun      111


2. FORECAST (01 JUNE - 03 JUNE)
Date   T index  Conditions       MUFs                              
01 Jun    80    Poor             15 to 20% below predicted monthly 
                                 values
02 Jun    60    Poor             20 to 30% below predicted monthly 
                                 values    
03 Jun    70    Fair-poor        20 to 30% below predicted monthly 
                                 values   

COMMENT: ASWFC Preliminary HF Communications Warning 56 was issued 
on 31 May and is current for 2-4 Jun. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 31-May were near predicted 
monthly values with depressions of up to 30% observed during 
local night. Spread F was observed at Hobart, Canberra and Perth 
during local night hours. MUFs are expected to be near predicted 
monthly values to depressed by up to 20% on 01-Jun. Stronger 
depressions are expected over 02-03 Jun due to anticipated geomagnetic 
activity beginning in the second half of 01-Jun. Shortwave fadeouts 
are probable.

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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