I am also struggling to understand this chart with the yellow bars, but it looks to me as though it is in perfect harmony with Hall's film, viz.,
Saturday 28 April - SUNNY ALL DAY
Sunday 29 April - SUNNY ALL DAY
Monday 30 April - NO SUN
Tuesday 1 May - NO SUN
Wednesday 2 May - NO SUN
Thursday 3 MAY - ONLY 1 HOUR OF SUN
Looking at that, I would say that Hall has actually understated the contrast between Sunday and Thursday.
Where are your Sagres charts? I can't find them
The first relevant test is to compare the Sagres and Faro charts for the period. This comparison quite clearly shows there were large differences between the two, hardly surprising as they are over 50 miles apart in two halves (Barlavento and Sotovento) of the Algarve known to have different patterns.
As Faro is 40 miles to the E of Luz, while Sagres is 14ml to the W of Luz, a first level conclusion would be to prefer the Sagres version as likely to be more accurate, based purely on proximity.
Then there is a comparison of Sagres with Mr Hall's chart. As the latter is stated to have been constructed in Luz itself, if its provenance is good, it would clearly trump the Sagres figures. I have appended a copy of Mr Hall's chart at the end of this post.
As a check, I looked at the Sky video taken in the morning of 4 May 2007, where the McCanns are being driven to Portimão to give statements.
That matches Mr Hall's chart for the time. The sun was casting strong shadows in the video, thus matching Mr Hall's chart, which also depicts sunshine at the time.
The wind direction and speed for Sagres appears to be a paid service, and who knows, I may be curious enough to cough up the dosh.
My interest happens to be in the sniffer dogs brought in late on 4 May, given that a wind should have affected their findings. But I would not turn down a two birds with one stone result.
Mr Hall's chart shows the wind direction at 12 hourly intervals. Unfortunately, it does not show the wind speed, which affects both The Last Photo and the sniffer dogs. Mr Hall's source should have this data, as it is one of the most basic functions of a weather station.
Mr Hall's chart depicts the wind direction as being from the NW or W in the main, with the occasional SW. It never depicts weather (clouds) coming from the E = Faro. It consistently depicts weather (clouds) coming from the W = Sagres.
Taking both into account, Sagres as a source is clearly superior to Faro, based on wind direction and proximity.
The question then is, is Mr Hall's chart superior to the Sagres weather station? I, for one, would be more certain of this if there was more information re Mr Hall's source and the mechanics of the weather station reported to be in Luz.
Here is Mr Hall's weather chart, captured from the video "When Madeleine Died?"
