[Ips-whfpr] IPS Weekly Prop. Report (18 April 01)

[rwc]

SUBJ: IPS WEEKLY HF PROPAGATION REPORT
ISSUED AT 18/0200Z APRIL 2001 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
AUSTRALIAN REGION SUMMARY AND FORECAST
1. SUMMARY (11 APRIL - 17 APRIL)
Date   T index   Conditions        
11 Apr  120      Fair              
MUFS:
   Equatorial PNG Region:
      Enhanced by 15% during local day,
      Near predicted monthly values during local night.
      Depressed by 15% after local dawn.
   Northern Australian Region:
      Mostly near predicted monthly values,
      Depressed by 40% after local dawn.
   Southern Australian and New Zealand Region:
      Mostly near predicted monthly values,
      Depressed by 55% after local dawn.
   Antarctic Region (Casey/Scott Base):
      Depressed by 40% over the UT day.

12 Apr   70      Normal-fair       
MUFS:
   Equatorial PNG Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian and New Zealand Region:
      Depressed by 45% during local day,
      Depressed by 15% during local night.
   Antarctic Region (Casey/Scott Base):
      PCA.

13 Apr  134      Normal-fair       
MUFS:
   Equatorial PNG Region:
      Near predicted monthly values during local day,
      Depressed by 15% during local night.
   Northern Australian Region:
      Near predicted monthly values during local day,
      Enhanced by 20% during local night.
      Enhanced by 15% after local dawn.
   Southern Australian and New Zealand Region:
      Mostly near predicted monthly values,
      Depressed by 35% after local dawn.
   Antarctic Region (Casey/Scott Base):
      Enhanced 15% to depressed 15% and absorption over the UT day.

14 Apr   94      Fair              
MUFS:
   Equatorial PNG Region:
      Mostly near predicted monthly values,
      Enhanced by 15% after local dawn.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian and New Zealand Region:
      Depressed by 35% during local day,
      Depressed by 25% during local night.
   Antarctic Region (Casey/Scott Base):
      Depressed by 15% over the UT day.

15 Apr  119      Normal            
MUFS:
   Equatorial PNG Region:
     Enhanced by 15% during local day,
     Near predicted monthly values during local night.
  Northern Australian Region:
     Near predicted monthly values during local day,
     Depressed by 15% during local night.
  Southern Australian and New Zealand Region:
     Near predicted monthly values.
  Antarctic Region (Casey/Scott Base):
     Near predicted monthly values over the UT day.


16 Apr  132      Fair-normal       
MUFS:
   Equatorial PNG Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian and New Zealand Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base):
      Near predicted monthly values over the UT day.
      Absorption observed.

17 Apr  126      Fair-normal       
MUFS:
   Equatorial PNG Region:
      Near predicted monthly values.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian and New Zealand Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base):
      Near predicted monthly values over the UT day.

Predicted Monthly T index for April: 120

COMMENT: Shock in solar wind observed at 0003UT on 18 April, associated
with recent X14 flare.  Also, a large previously flaring region (sec 9393) 
is due back around 18 Apr. This region showed decay on leaving the solar 
disk on its previous transit. If this region does return, (there is a
possible brightening on the northeast limb in Yohkoh softxray
imagery), or represented an active solar longitude, increased
flare activity may be experienced after this date.
2. FORECAST (18 APRIL - 24 APRIL) 
MUFS: depressed and degraded conditions expected for mid to high
latitudes 18-19 April. Low latitudes should remain near nronal.
Propagation conditions: Fair 18-19-Apr, otherwise normal. SWFs possible.
T index:  90 18-19 April
	  120 rest of week.
COMMENT: IPS HF Communications Warning 26 was issued on 16 April and is current for interval  18-19 April. 
3. OUTLOOK (25 APRIL - 25 MAY)
Degraded HF propagation conditions possible:
27-Apr to 28-Apr,05-May,12 May

IPS Radio and Space Services      | email: asfc at ips.gov.au
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