[Ips-whfpr] ASWFC Weekly Prop. Report (01 October 25) issued 0047 UT on 01 Oct 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC WEEKLY HF PROPAGATION REPORT
ISSUED ON 01 OCTOBER 2025 
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (24 SEPTEMBER - 30 SEPTEMBER)
Date   T index   Conditions        
24 Sep  127      Normal            
MUFS:
   Cocos Island Region:
      Enhanced by 20% during local day.
      Enhanced by 100% during local night.
   Niue Island Region:
      Enhanced by 20-40%.
      Near predicted monthly values during local day.
      Enhanced by 20-30%.
   Southern Australian Region:
      Mostly near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

25 Sep  129      Fair-normal       
MUFS:
   Cocos Island Region:
      Enhanced by 55% during local day.
      Enhanced by 85% during local night.
   Niue Island Region:
      Enhanced by 15-20% during local day.
   Northern Australian Region:
      Enhanced by 15%.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

26 Sep  119      Normal            
MUFS:
   Cocos Island Region:
      Enhanced by 20-25%.
   Niue Island Region:
      Enhanced by 45% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 25% during local night.
   Southern Australian Region:
      Enhanced by 15-30%.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

27 Sep  130      Normal            
MUFS:
   Cocos Island Region:
      Enhanced by 30% during local day.
      Enhanced by 30% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 50% during local night.
   Southern Australian Region:
      Enhanced by 20-35%.
   Antarctic Region (Casey/Davis/Mawson):
      Enhanced by 20% over the UT day.

28 Sep  136      Normal            
MUFS:
   Cocos Island Region:
      Enhanced by 45% during local day.
      Enhanced by 65% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 50% during local night.
      Enhanced by 25% after local dawn.
   Southern Australian Region:
      Enhanced by 25% during local day.
      Enhanced by 30% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

29 Sep  130      Normal-fair       
MUFS:
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Niue Island Region:
      Enhanced by 20-30%.
   Northern Australian Region:
      Enhanced by 15-25%.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 20% during local night.
      Depressed by 15-30% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

30 Sep   88      Poor-fair         
MUFS:
   Cocos Island Region:
      Enhanced by 30% during local day.
      Near predicted monthly values during local night.
      Enhanced by 45% after local dawn.
   Niue Island Region:
      Enhanced by 20-30%.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Depressed by 20-30%.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 30% over the UT day.

Comment: G1 geomagnetic conditions were observed in the 
Australian region on UT day 30-Sep associated with southward 
orientated interplanetary magnetic field conditions. 
Planetary conditions reached G3 on 30-Sep. The cause of 
the recent enhanced southward IMF conditions is not 
definitive but appears to have preceded a coronal hole 
wind stream entry. This geomagnetic activity subsequently 
degraded middle to high latitude HF communications.

Predicted Monthly T index for September: 109

2. FORECAST (01 OCTOBER - 07 OCTOBER) 
MUFS: Southern region MUFs depressed 20% on 01-Oct, with
northern Australian MUFs expected to be near predicted 
monthly values to 15% enhanced. Southern region MUFs mildly
depressed on 03-05 Oct in association with 27 day recurrent 
geomagnetic patterns. MUFs near predicted monthly values
on other days.

Propagation conditions: Poor to Fair on 1 Oct,  
fair on 03-05 Oct. Otherwise normal. Isolated SWFs probable 
during the week.

T index: 50 for southern Australian region on 01-Oct. 120 for northern 
Australian region on 01-Oct. 100 for other days of the week.
ASWFC SWF HF Communications Warning 86 was issued on 28 September 
and is current for 29 Sep to 1 Oct. ASWFC HF Communications Warning 
88 was issued on 1 October and is current for 1 Oct only.

3. OUTLOOK (08 OCTOBER - 07 NOVEMBER)
Degraded HF propagation conditions possible:
12-13 Oct,  30 Oct

PLEASE NOTE:
Space weather conditions can frequently be determined by short 
timescale events that cannot be forecast a week in advance,
particularly at solar maximum.

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