[Ips-dhfpr] ASWFC Daily HF Prop Report - 19 March 26 issued 2330 UT on 19 Mar 2026 [SEC=OFFICIAL]

[Australian Space Weather Forecasting Centre]

SUBJ: ASWFC DAILY HF PROPAGATION REPORT
ISSUED AT 2330UT/19 MARCH 2026
FROM THE AUSTRALIAN SPACE WEATHER FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST

1. SUMMARY (19 MARCH) 
Date   T index  Conditions    
19 Mar    83    Normal         

Flares: none.

MUFs:
   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.

PCA Event : No event.

Monthly T index:
Month  T index
Feb      98
Mar      87
Apr      85


2. FORECAST (20 MARCH - 22 MARCH)
Date   T index  Conditions       MUFs                              
20 Mar    75    Fair             Initially near predicted monthly 
                                 values then becoming depressed 
                                 by up to 20%
21 Mar    55    Fair             Depressed by up to 20%    
22 Mar    65    Normal-fair      Depressed 10 to 15%/near predicted 
                                 monthly values   

COMMENT: ASWFC Preliminary HF Communications Warning 27 was issued 
on 19 March and is current for 20-21 Mar. Maximum usable frequencies 
(MUFs) in the Australian region on UT day 19-Mar were near predicted 
monthly values during the local day with depressions of 25% at 
times during local night hours in the northern Australian region. 
These lower latitude ionospheric depressions were not related 
to any geomagnetic activity. Spread F was observed at Hobart 
during local night hours. Equatorial scintillation was observed 
at Niue 19/0722-0759UT. The anticipated geomagnetic storm activity 
expected to start from late in the UT day on 19-Mar with subsequent 
post dawn middle latitude ionospheric MUF depressions on 20-Mar 
has not eventuated. MUFs are now expected to be near predicted 
monthly values for most of the UT day 20-Mar, then becoming 20% 
depressed later in the UT day (after local dawn 21-Mar). Southern 
Australian regional MUFs are expected to be depressed by up to 
15-20% over 21-Mar to 22-Mar due to an anticipated increase in 
geomagnetic activity from two CME arrivals and coronal hole wind 
streams.

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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