[Ips-dhfpr] ASWFC Daily HF Prop Report - 18 May 26 issued 2330 UT on 18 May 2026 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/18 MAY 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (18 MAY) 
Date   T index  Conditions    
18 May    39    Fair           

Flares: none.

MUFs:
   Cocos Island Region:
      No data available during local day.
      No data available during local night.
   Niue Island Region:
      Depressed by 20% during local day.
      Depressed by 30% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 25% during local night.
   Southern Australian Region:
      Depressed by 15% during local day.
      Depressed by 30% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

PCA Event : No event.

Monthly T index:
Month  T index
Apr      74
May      71
Jun      68


2. FORECAST (19 MAY - 21 MAY)
Date   T index  Conditions       MUFs                              
19 May    40    Normal           15 to 20% below predicted monthly 
                                 values
20 May    55    Normal           Near predicted monthly values    
21 May    65    Normal           Near predicted monthly values   

COMMENT: ASWFC HF Communications Warning 49 was issued on 18 
May and is current for 18-19 May. Maximum Usable Frequencies 
(MUFs) were near predicted monthly values in the northern Australian 
region during local day, but depressed by 25% during local night. 
MUFs were depressed by 15-30% in southern Australia over the 
UT day. Spread-F was observed at Hobart and Canberra during local 
night hours. MUFs are expected to be 15-20% depressed on 19-May, 
recovering to near predicted monthly values over 20-21 May.

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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