[Ips-wsgr] ASWFC Weekly Solar and Geophysical Report (18 April 25) issued 0008 UT on 18 Apr 2025 [SEC=OFFICIAL]

Fri Apr 18 10:08:38 AEST 2025

SUBJ: ASWFC WEEKLY SOLAR AND GEOPHYSICAL REPORT 
ISSUED ON 18 APRIL 2025
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx

1. SUMMARY (11 APRIL - 17 APRIL)
Date     11    12    13    14    15    16    17
10cm    170   165   164   152   153   148   151
AFr      14    13     0     0     0    43  ( 10)
Aaus      9    11    10     9    14    33  ( ??)
T       132   137   112   116   112   102    99

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

11 Apr 
Solar:        R1, with an M1.0 at 1650UT, and an M1.0 at 
              2220UT
Geomagnetic:  G0
Frequencies:  
   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 
Solar:        R1, with an M1.0 at 2220UT, an M1.1 at 0445UT, 
              an M1.2 at 0549UT, an M1.0 at 0719UT, an M2.0 at 
              1117UT, an M2.7 at 1143UT, an M1.3 at 1512UT, and 
              an M1.6 at 2203UT
Geomagnetic:  G0
Frequencies:  
   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 
Solar:        R1, with an M1.1 at 0405UT, an M2.3 at 0452UT, 
              an M1.0 at 0652UT, an M1.4 at 0955UT, an M1.2 at 
              1542UT, an M3.2 at 1851UT, and an M1.6 at 2202UT
Geomagnetic:  G0
Frequencies:  
   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 
Solar:        R1, with an M1.4 at 0605UT, and an M4.2 at 
              0650UT
Geomagnetic:  G0
Frequencies:  
   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 
Solar:        R1, with an M1.5 at 1020UT, and an M1.3 at 
              1814UT
Geomagnetic:  G1
In the BOM magnetometer data for 15 Apr, a weak (10nT) impulse 
was observed at 1722UT.
Frequencies:  
   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.

16 Apr 
Solar:        R0
Geomagnetic:  G1
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Enhanced by 15% during local night.
   Niue Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Northern Australian Region:
      Mostly near predicted monthly values.
   Southern Australian Region:
      Mostly near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 25% over the UT day.

17 Apr 
Solar:        R0
Geomagnetic:  G0
In the BOM magnetometer data for 17 Apr, a weak (14nT) impulse 
was observed at 0403UT.
Frequencies:  
   Cocos Island Region:
      Enhanced by 20% during local day.
      Enhanced by 35% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Depressed by 30% during local day.
      Depressed by 25% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 25% over the UT day.

2. FORECAST (18 APRIL - 24 APRIL)
Solar: 
R0-R1

Geomagnetic:  
G1-G2 over 22-24 Apr. G0 other days.

Frequencies:  

Depressed by 10-20% over 18-19, particularly during local dawn, 
due to a recent CME event. MUFs may become depressed over 23-24 Apr
due to coronal hole activity. Near predicted values 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