[Ips-wsgr] ASWFC Weekly Solar and Geophysical Report (17 April 26) issued 0044 UT on 17 Apr 2026 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC WEEKLY SOLAR AND GEOPHYSICAL REPORT 
ISSUED ON 17 APRIL 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx

1. SUMMARY (10 APRIL - 16 APRIL)
Date     10    11    12    13    14    15    16
10cm     94    93    99    99   101   105   108
AFr      16    10     7     3     2     3  (  4)
Aaus     13    10     5     1     0     2  (  1)
T        79    67    65    61    63    61    60

Solar:        Solar flare activity
Geomagnetic:  Geomagnetic activity observed for Australian region.
Frequencies:  Australian ionospheric F2 critical frequencies

10 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Niue Island Region:
      Mostly near predicted monthly values.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Depressed by 15-20% during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 30% over the UT day.

11 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Southern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 30% over the UT day.

12 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 15% during local day.
      Depressed by 20% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Southern Australian Region:
      15% depressed to near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.

13 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 40% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

14 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 15% during local day.
      Depressed by 30% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 20% 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.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

15 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 35% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
      Depressed by 20% after local dawn.
   Northern Australian Region:
      Mostly near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

16 Apr 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 20% during local day.
      Depressed by 35% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 30% during local night.
   Southern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

Comment: Ionospheric Maximum Usable Frequencies (MUFs) were
in general below monthly predicted monthly values during the 
period 11-16 Apr and this is possibly attributed to an earlier 
long steady decline in solar flux emission as there as there 
was little geomagnetic activity during the week. More recently 
solar flux values are showing a slight increase.
 
2. FORECAST (17 APRIL - 23 APRIL)
Solar: 
R0, chance R1

Geomagnetic:  
G1 periods late on 17 Apr, G1, chance G2 18-19 Apr. 
G1 periods on 18 Apr. Geomagnetic activity due to a
large coronal hole.  G0 on other days.

Frequencies:  
Southern Australian region MUFs are expected to be
briefly depressed after local dawn on 17 Apr, and
15-20% depressed 18-20 Apr. MUFs near predicted 
monthly values on other days.


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