[Ips-hf-warning] IPS HF COMMS WARNING

[rwc]

SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 01/23
ISSUED AT 10/2157Z APRIL 2001
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

DEGRADED HF PROPAGATION CONDITIONS ARE EXPECTED OVER
11 TO 13 APR PERIOD AFTER THE ANTICIPATED ARRIVAL OF
TWO SHOCKS ASSOCIATED WITH THE M7.9 AND X2.3 FLARES/
FULL HALO CMES OBSERVED AFTER 1534UT ON 9APR AND 0517UT
ON 10 APR, RESPECTIVELY.

BOTH FLARES/CMES ORIGINATED FROM REGION 9415 WHICH REMAINS
MAGNETICALLY COMPLEX. THIS REGION COULD PRODUCE FURTHER
M- AND X-CLASS FLARES OVER THE FOLLOWING DAYS.

DEGRADED HF PROPAGATION CONDITIONS EXPECTED
FROM 11-13 APRIL 2001
IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND
FOLLOW ON HF WARNING FROM HF WARNING: 22
-------------------------------------------------------------
SOLAR ACTIVITY FORECAST       HF COMMS FADEOUTS             
11 Apr:  Moderate to high     Probable             
12 Apr:  Moderate to high     Probable             
13 Apr:  Moderate to high     Probable             

HF COMMUNICATIONS FORECAST (AUSTRALIAN/NEW ZEALAND REGION)
                                   FREQUENCY BANDS  
       T-index  MUFs          2  4  6  8 12 16 22 26
-------------------------------------------------------------
11 Apr   83    -15%/normal    2  4  6  8 12 12 16 22 
12 Apr   83    -15%           2  4  6  8 12 12 16 22 
13 Apr   95    normal/-10%    2  4  6  8 12 16 16 22 

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