[Ips-dhfpr] ASWFC Daily HF Prop Report - 10 May 24 issued 2330 UT on 10 May 2024 [SEC=OFFICIAL]

[Regional Warning Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/10 MAY 2024
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (10 MAY) 
Date   T index  Conditions    
10 May   121    Normal-poor    

Flares    Max     Fadeout    Freq.  Sectors
  M2.7 09/2241UT  possible   lower  East Pacific/
                                    North American
  M1.6 09/2351UT  possible   lower  West Pacific
  M1.4    0329UT  possible   lower  E. Asia/Aust.
  M1.3    0624UT  possible   lower  Mid East/Indian
  X3.9    0654UT  probable   all    Mid East/Indian
  M5.9    1411UT  possible   lower  South American/
                                    Atlantic
  M1.2    1741UT  possible   lower  South American/
                                    Atlantic
  M1.1    1832UT  possible   lower  East Pacific/
                                    North American
  M1.8    1850UT  possible   lower  East Pacific/
                                    North American
  M3.8    2108UT  possible   lower  East Pacific/
                                    North American

MUFs:
   Cocos Island Region:
      Enhanced by 20%.
   Niue Island Region:
      Mostly near predicted monthly values.
      Enhanced by 40% after local dawn.
   Northern Australian Region:
      Mostly near predicted monthly values.
      Depressed by 25% after local dawn.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Depressed by 50% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Enhanced by 15% over the UT day.
      Proton event in progress, increased absorption observed.

PCA Event : 10MeV Proton/PCA Event Began 10 05 2024 1350UT and is in progress

Monthly T index:
Month  T index
Apr      125
May      114
Jun      116


2. FORECAST (11 MAY - 13 MAY)
Date   T index  Conditions       MUFs                              
11 May    20    Poor             40 to 50% below predicted monthly 
                                 values
12 May    65    Poor-fair        20 to 30% below predicted monthly 
                                 values    
13 May    90    Fair-normal      Near predicted monthly values   

COMMENT: ASWFC SWF HF Communications Warning 50 was issued on 
9 May and is current for 10-12 May. ASWFC HF Communications Warning 
51 was issued on 10 May and is current for 11 May only. Maximum 
usable frequencies (MUFs) on UT day 10-May were near predicted 
monthly values until the local dawn period, after which becoming 
depressed by 30-50% due to the onset of a severe geomagnetic 
storm. A shortwave fadeout was observed 10/0619-1059UT in association 
with the X3 flare. Strong spread F was observed at southern Australian 
region ionosonde locations during local night hours. MUFs are 
expected to be depressed by 40% on 11-May, with extremely degraded 
HF conditions. Further ionospheric depressions, though not as 
severe, are likely on 12-May. Frequent shortwave fadeouts are 
expected.

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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