[Ips-whfpr] ASWFC Weekly Prop. Report (16 April 25) issued 0045 UT on 16 Apr 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC WEEKLY HF PROPAGATION REPORT
ISSUED ON 16 APRIL 2025 
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (09 APRIL - 15 APRIL)
Date   T index   Conditions        
09 Apr  133      Fair-normal       
MUFS:
   Cocos Island Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Niue Island Region:
      Mostly near predicted monthly values.
      Enhanced by 20% after local dawn.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
      Enhanced by 20% after local dawn.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 25% over the UT day.

10 Apr  136      Fair-normal       
MUFS:
   Cocos Island Region:
      Enhanced by 20-30%.
   Niue Island Region:
      Enhanced by 25-30%. 
   Northern Australian Region:
      Enhanced by 20% during local day.
      Enhanced by 15% during local night.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Hobart depressed 20-30% early in UT day.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 25% over the UT day.

11 Apr  132      Normal            
MUFS:
   Cocos Island Region:
      Enhanced by 30% during local day.
      Enhanced by 40% during local night.
   Niue Island Region:
      Enhanced by 20% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

12 Apr  137      Normal-fair       
MUFS:
   Cocos Island Region:
      Enhanced by 15% during local day.
      Enhanced by 35% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 25% during local night.
      Enhanced by 25% after local dawn.
   Northern Australian Region:
      Mostly near predicted monthly values.
      Enhanced by 20% after local dawn.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Depressed by 30% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

13 Apr  112      Fair              
MUFS:
   Cocos Island Region:
      Enhanced by 15% during local day.
      Depressed by 35% during local night.
   Niue Island Region:
      Enhanced by 25% during local day.
      Enhanced by 15% during local night.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Depressed by 25% during local day.
      Depressed by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.

14 Apr  116      Fair-normal       
MUFS:
   Cocos Island Region:
      Enhanced by 25% during local day.
      Enhanced by 45% during local night.
   Niue Island Region:
      Enhanced by 30% during local day.
      Near predicted monthly values during local night.
      Enhanced by 20% after local dawn.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Southeast depressed by 25% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.

15 Apr  112      Normal-poor       
MUFS:
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Mostly near predicted monthly values.
      Enhanced by 20% after local dawn.
   Southern Australian Region:
      Near predicted monthly values.
      Depressed 15-20% pre-dawn period.
      Depressed 10-15% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

Comment: The Australian regional geomagnetic field 
reached G1 late in the UT day on 15-Apr, with 
planetary conditions reaching G2, following a CME 
arrival. The Australian region ionospheric response 
to this ongoing geomagnetic activity has been limited 
to depressions of up to 20% during the predawn period, 
with Hobart and Canberra only mildly depressed by 
15% after dawn this morning. 


Predicted Monthly T index for April: 115

2. FORECAST (16 APRIL - 22 APRIL) 
MUFS: MUFs are expected to be depressed 15-20% at times 
for the southern Australian region on 16-Apr. Northern 
Australian region MUFs are mostly expected to remain 
near normal. Southern Australian region MUFs may
be briefly depressed after local dawn on 17-Apr. Geomagnetic
27 day recurrent patterns suggest that southern Australian 
region MUFs may become depressed by 15% during 23-24 Apr. 
MUFs are expected to be near predicted monthly values on 
other days.

Propagation conditions: Fair on 16-17 Apr, and on 
23-24 Apr. Otherwise normal.

T index: 115
ASWFC HF Communications Warning 39 was issued on 16 April and 
is current for 16 Apr only.

3. OUTLOOK (23 APRIL - 23 MAY)
Degraded HF propagation conditions possible:
23-24 Apr,  1-2 May,  6-7 May,  14-15 May,  19-21 May

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