[Ips-hf-warning] IPS HF COMMS WARNING

[rwc]

SUBJ: IPS HF RADIO COMMUNICATIONS WARNING 01/56
ISSUED AT 11/2220Z OCTOBER 2001
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

A SHOCK FROM A RECENT MASS EJECTION ARRIVED AT 1619UT
ON 11 OCT.THE NORTH-SOUTH COMPONENT OF THE INTERPLANETARY 
MAGNETIC FIELD FLUCTUATED SOUTHWARD ON SHOCK ARRIVAL, THEN TURNED
STRONGLY NORTHWARD, REDUCING GEOEFFECTIVENESS. SOLAR WIND SPEED
CURRENTLY MODERATELY ELEVATED AT AROUND 550KM/SEC. GEOMAGNETIC
ACTIVITY IS EXPECTED TO RAPIDLY DECLINE TODAY DUE TO THE NORTHWARD
IMF.

DEGRADED HF PROPAGATION CONDITIONS EXPECTED BRIEFLY AFTER 
LOCAL DAWN THIS MORNING, THEN RETURNING TO NORMAL. 
DEPRESSIONS MAY PERSIST LONGER AT HIGH LATITUDES.

IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND
FOLLOW ON HF WARNING FROM HF WARNING: 55
-------------------------------------------------------------
SOLAR ACTIVITY FORECAST       HF COMMS FADEOUTS             
12 Oct:  low to moderate      Possible             

HF COMMUNICATIONS FORECAST (AUSTRALIAN/NEW ZEALAND REGION)
                                   FREQUENCY BANDS  
       T-index  MUFs          2  4  6  8 12 16 22 26
-------------------------------------------------------------
12 Oct   100   -15%/normal    2  4  6  8 12 12 16 22 

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