"WSPR Propagation Analysis" for WSPR spots of G3XBM on 10 m

Roger, G3XBM wrote:
Nothing at all was seen until mid-afternoon and then the band just opened wide!  
K9AN (6505km) last spotted my 2W signal at 2308z, which is after midnight local time and HOURS after the band has normally died out. It had been dark for hours. One wonders if this was F2 or even multi-hop Es? I wonder what was happening on 6m transatlantic?  I must check.
(Spots made on 2014-04-08) Click to visit the article.

I was interested, so I made an WSPR Propagation Analysis of the spots on that day and the days before. The second table shows the last spot at 23:08 UTC, but also reveals the rapid change in propagation around 22:20 UTC.

How to read the table 
In the analysis above, I show the "Calculated Lowest possible Power" in milliwatt and the hours of the day in UTC. The lower the "Calculated Lowest Possible Power", the better the propagation.

To compare the propagation over several days, 

I included 2014-03-28 till 2014-04-08.


Roger is refering to WSPR spots made on 2014-04-08.
At the bottom of the table above.
From 10 UTC to 22 UTC the propagation gets better.
The best propagation occurred in the spot with the red star made on 22:20 UTC.



Even more spectacular
The best propagation on 2014-03-28, at the top of the table, occurred between 13:00 and 15:59 UTC in the aftenoon.
But even more spectacular is the change in propagation in the 3 spots * that were made between 22:00 and 22:22 UTC, that show a very rapid chang in propagation. (See the red arrows)

Thanks to Roger for the interesting experiments with WSPR.