[Ips-wsgr] ASWFC Weekly Solar and Geophysical Report (19 December 25) issued 0048 UT on 19 Dec 2025 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC WEEKLY SOLAR AND GEOPHYSICAL REPORT 
ISSUED ON 19 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx

1. SUMMARY (12 DECEMBER - 18 DECEMBER)
Date     12    13    14    15    16    17    18
10cm    135   122   119   118   117   119   116
AFr      19     8     5     5     6    10  ( 14)
Aaus     26    10     4     5     9    11  ( 11)
T        81    28    73   110    81    82    96

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

12 Dec 
Solar:        R1, with an M2.0 at 0505UT
Geomagnetic:  G1
Frequencies:  
   Cocos Island Region:
      Mostly near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 30% during local night.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
      Depressed by 35% after local dawn.
   Southern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values during local night.
      Depressed by 35% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 15% over the UT day.

13 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Depressed by 50% during local day.
      Depressed by 35% during local night.
      Depressed by 20% after local dawn.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 30% during local night.
      Enhanced by 20% after local dawn.
   Northern Australian Region:
      Depressed by 35% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Depressed by 30% during local day.
      Near predicted monthly values during local night.
      Depressed by 25% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 25% over the UT day.

14 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Depressed by 15% during local day.
      Near predicted monthly values.
   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.

15 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Mostly near predicted monthly values.
   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 20% during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

16 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values.
   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.

17 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

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

Comment: In the Australian region G1 periods were observed on 
12-Dec, possibly due to a solar wind corotating interaction region
prior to the Earth entering a coronal hole high speed wind stream. 
Planetary conditions reached G1 on 12,13 and 18-Dec.

2. FORECAST (19 DECEMBER - 25 DECEMBER)
Solar: 
R0 19-24 Dec. R1 25 Dec.

Geomagnetic:  
G1 periods possible during the interval 21-24 Dec. G0 on other days.

Frequencies:  
Southern Australian regional MUFS may become mildly (15%)
depressed after local dawn during the interval 22-24 Dec.
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