[Ips-wsgr] ASWFC Weekly Solar and Geophysical Report (12 December 25) issued 0153 UT on 12 Dec 2025 [SEC=OFFICIAL]

Fri Dec 12 12:53:18 AEDT 2025

SUBJ: ASWFC WEEKLY SOLAR AND GEOPHYSICAL REPORT 
ISSUED ON 12 DECEMBER 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx

1. SUMMARY (05 DECEMBER - 11 DECEMBER)
Date     05    06    07    08    09    10    11
10cm    206   200   194   186   183   168   146
AFr      10    15     5     1     4    16  ( 18)
Aaus     11    10     5     2     3    16  ( 20)
T       116   135   146   132   154   148   117

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

05 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 15% during local night.
   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.

06 Dec 
Solar:        R2, with an M1.1 at 1921UT, and an M8.1 at 2039UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Mostly near predicted monthly values.
      Enhanced by 20% after local dawn.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 25% during local night.
   Northern Australian Region:
      Enhanced by 20% 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.

07 Dec 
Solar:        R0
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
      Enhanced by 25% after local dawn.
   Niue Island Region:
      Enhanced by 40% during local day.
      Enhanced by 75% during local night.
      Enhanced by 30% after local dawn.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 30% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

08 Dec 
Solar:        R3, with an M2.4 at 0012UT, an M2.0 at 0036UT, 
              an X1.1 at 0501UT, an M1.8 at 0654UT, an M1.0 at 
              1306UT, an M3.1 at 2117UT, and an M1.2 at 2228UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
      Enhanced by 25% after local dawn.
   Niue Island Region:
      Enhanced by 15% during local day.
      Enhanced by 25% 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 during local day.
      Enhanced by 20% during local night.
      Enhanced by 25% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

09 Dec 
Solar:        R1, with an M2.0 at 0058UT, 
              an M1.0 at 0730UT, an M1.6 at 0747UT, an M1.5 at 
              1514UT, and an M1.5 at 2327UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 30% during local day.
      Enhanced by 50% during local night.
      Enhanced by 25% after local dawn.
   Niue Island Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 20% during local night.
      Enhanced by 25% after local dawn.
   Southern Australian Region:
      Enhanced by 25% during local day.
      Enhanced by 20% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

10 Dec 
Solar:       R1, with an M1.2 at 0422UT, an M1.9 at 0737UT, 
            an M1.0 at 0955UT, an M1.6 at  1343UT, and an
            M4.4 at 2208UT
Geomagnetic:  G1
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Enhanced by 15% during local day.
      Enhanced by 35% during local night.
   Northern Australian Region:
      Enhanced by 25% during local day.
      Enhanced by 25% during local night.
   Southern Australian Region:
      Enhanced by 15% during local day.
      Enhanced by 15% during local night.
      Enhanced by 20% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

11 Dec 
Solar:        R0
Geomagnetic:  G1
In the BOM magnetometer data for 11 Dec, a weak (24nT) impulse 
was observed at 1500UT.
Frequencies:  
   Cocos Island Region:
      Mostly near predicted monthly values.
   Niue Island Region:
      Enhanced by 20% during local day.
      Enhanced by 15% during local night.
   Northern Australian Region:
      Mostly near predicted monthly values.
      Enhanced by 25% after local dawn.
   Southern Australian Region:
      Enhanced by 20% during local day.
      Near predicted monthly values during local night.
      Depressed by 20% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

2. FORECAST (12 DECEMBER - 18 DECEMBER)
Solar: 
R1-R2 conditions are forecast for 12-Dec, decreasing to R1 over 
13-14 Dec as several flare active sunspot regions rotate over the 
visible surface of the disk. Declining to R0 thereafter.

Geomagnetic:  
G0-G1 level over 12-Dec, as the effects of a previous Coronal Mass
 Ejection  impact begin to subside. G0-G1 conditions will remain 
over 13-14 Dec, as an equatorial coronal hole rotates into a 
geoeffective position. This will decline towards G0 from 15-Dec.

Frequencies:  
MUFs near predicted monthly values on 12-Dec due to Geomagnetic
Activity. Remaining at near predicted monthly values during 13-14 
Dec due to coronal hole high speed wind stream effects, with possible
Enhancements seen thereafter.

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