SB PROP @ ARL $ARLP028
ARLP028 Propagation de K7RA

ZCZC AP28
QST de W1AW 
Propagation Forecast Bulletin 28 ARLP028
From Tad Cook, K7RA
Seattle, WA July 9, 2021
To all radio amateurs 

SB PROP ARL ARLP028
ARLP028 Propagation de K7RA

Solar activity continues its increase. In last week's bulletin
ARLP027 average daily sunspot number was 34.7, and this week it
increased to 55.6.

Average daily solar flux increased from 86.9 to 88.9.

Despite solar flare activity pushing a sudden ionospheric
disturbance and a dramatic shortwave radio blackout, at least the
average daily planetary A index for the week was only 5.7, down from
6.1 in last week's bulletin. The average middle latitude A index
was also 6.1 last week, and it was 6.3 this week.

The flare was an X1.5-Class event, the biggest since September 2017
and the 
		
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