[Ips-wsgr] ASWFC Weekly Solar and Geophysical Report (20 March 26) issued 0100 UT on 20 Mar 2026 [SEC=OFFICIAL]

Fri Mar 20 12:00:29 AEDT 2026

SUBJ: ASWFC WEEKLY SOLAR AND GEOPHYSICAL REPORT 
ISSUED ON 20 MARCH 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx

1. SUMMARY (13 MARCH - 19 MARCH)
Date     13    14    15    16    17    18    19
10cm    120   112   109   111   111   113   106
AFr      19    19    14    10     4     4  (  9)
Aaus     12    24    11     6     2     1  (  1)
T       109   112    89    87    85    87    83

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

13 Mar 
Solar:        R1, with an M1.1 at 0955UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Niue Island Region:
      Enhanced by 25% during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Mostly near predicted monthly values.
      Enhanced by 15% after local dawn.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

14 Mar 
Solar:        R0
Geomagnetic:  G1
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 35% during local night.
   Niue Island Region:
      Enhanced by 40% during local day.
      Enhanced by 40% during local night.
      Enhanced by 20% after local dawn.
   Northern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Enhanced by 15% during local day.
      Near predicted monthly values during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 30% over the UT day.

15 Mar 
Solar:        R1, with an M1.0 at 0939UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Mostly near predicted monthly values.
   Niue Island Region:
      Mostly near predicted monthly values.
   Northern Australian Region:
      Mostly near predicted monthly values.
   Southern Australian Region:
      Mostly near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Depressed by 20% over the UT day.

16 Mar 
Solar:        R1, with an M2.7 at 1215UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values.
   Niue Island Region:
      Enhanced by 30% during local day.
      Depressed by 15% during local night.
   Northern Australian Region:
      Enhanced by 20% during local day.
      Enhanced by 25% during local night.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

17 Mar 
Solar:        R1, with an M1.3 at 0904UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% during local night.
   Niue Island Region:
      Near predicted monthly values.
   Northern Australian Region:
      Enhanced by 20% during local day.
      Near predicted monthly values during local night.
   Southern Australian Region:
      Mostly near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

18 Mar 
Solar:        R1, with an M2.3 at 0839UT, and an M2.7 at 
              0843UT
Geomagnetic:  G0
Frequencies:  
   Cocos Island Region:
      Near predicted monthly values during local day.
      Depressed by 15% 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.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

19 Mar 
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.
      Depressed by 25% during local night.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Davis/Mawson):
      Near predicted monthly values over the UT day.

Comment: 
A coronal hole wind stream induced G1 periods on 14-Mar. Ionospheric
Maximum Usable Frequency (MUF) depressions of 15-20% were observed at 
only Hobart and Canberra on 15-Mar. Most of the isolated R1 flare activity 
observed during the week was from solar region AR4392. This region is now 
decaying. The R1(M2.7) flare activity on 16-Mar and 18-Mar had associated 
CMEs. The first CME was modelled to arrive late in the UT day on 19-Mar but 
has yet to eventuate. There is currently only two solar regions with spots on
the visible solar disk. The other region, AR4397 is small though is
currently growing.

2. FORECAST (20 MARCH - 26 MARCH)
Solar: 
R0, with isolated low level R1 flare activity.
No previously flare active solar regions are expected to 
return to eastern solar limb this week.

Geomagnetic:  
G1-G2 geomagnetic conditions are expected 20-21 Mar due 
to CME induced geomagnetic activity. In addition coronal hole 
wind streams are expected to contribute to geomagnetic activity 
over 21-23 Mar. G1 periods expected 22-23 Mar. G0 on other days 
of the week.

Frequencies: 
Australian regional ionospheric Maximum Usable Frequencies (MUFs) 
are expected to be mostly near predicted monthly values on 20-Mar. 
Regional MUFs are expected to be 15-20% depressed on 21-22 Mar if 
anticipated geomagnetic activity eventuates. Southern Australian 
region MUFs may be briefly depressed after local dawn during 
23-24 Mar. MUFs are expected to be near predicted monthly values 
on other days of the week.

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