[HCRA] K7RA Forecast

[Daniel J. Sullivan]

The K7RA Solar Update 
Seattle, Washington, June 24, 2005 -- Propagation guru Tad "That Lucky Ol' Sun" Cook, K7RA, reports: A projection shows active geomagnetic conditions on Friday, June 24, followed by unsettled to active on Field Day weekend, June 25-26. A planetary geomagnetic A index of 20 is predicted for June 24-26. These aren't great conditions for HF, but are not at the level of a geomagnetic storm like we had on Thursday June 23 when the planetary K index went all the way to seven, and the planetary A index was 48. Sunspot numbers and solar flux are expected to remain low, with solar flux around 85. 


Given the low sunspot numbers, 20 and 40 meters are going to be the best bands for working cross country, with 80 meters open after dark. 40 and 80 should be the best bands for working stations less than 1000 miles away, day or night. 


To review the past week, sunspots and solar flux numbers were lower. Average daily sunspot numbers dropped nearly 28 points from the previous week to 51.1. Average daily solar flux was off over 15 points to 87.7. The big geomagnetic activity of note was one day following our Thursday through Wednesday reporting period, on Thursday, June 23, when mid-latitude A index was 30 and planetary A index was 48. 


Sunspot numbers for June 16 through 22 were 67, 59, 50, 43, 47, 53 and 39 with a mean of 51.1. 10.7 cm flux was 98.1, 90.8, 90, 86.9, 86.1, 82.8 and 79.5, with a mean of 87.7. Estimated planetary A indices were 26, 14, 7, 7, 5, 4 and 7 with a mean of 10. Estimated mid-latitude A indices were 19, 9, 5, 3, 2, 1 and 6, with a mean of 6.4.