Not for the first time, all the talk at Spa-Francorchamps revolves around the weather.
Following the threat on Friday, yesterday we witnessed downfalls of almost Biblical proportions, complete with hailstones. Today, as one might expect, the circuit is bathed in bright sunshine, furthermore the temperatures are higher... albeit marginally.
Consequently this afternoon should in many ways be a bit of a lottery, however the facts is that barring a major upset Mercedes will score its tenth win of the season.
The German team's advantage in the dry is well documented, but yesterday's tour-de-force, whereby both Silver Arrows drivers were over 2s clear of their nearest rivals was frightening.
While Red Bull was able to capitalise on the conditions, Sebastian Vettel taking an impressive third, today looks to be another matter entirely with the Mercedes-powered teams likely to be the biggest challenge to the works outfit.
Having played its card close to its chest on Friday, Williams revealed a little in FP3, Valtteri Bottas leading the way, and while he starts today's race from sixth he must be a good bet for a podium.
McLaren has looked good all weekend and barring a late mistake in Q3 Jenson Button could have been nearer the front, the Briton a major fan of the Ardennes track.
One must never write-off Ferrari, particularly in the case of Fernando Alonso, while Kimi Raikkonen is also looking strong this weekend. However, in terms of grunt the Italian team will be on its back foot compared to its German rivals.
Other than McLaren and Williams, the other Mercedes team that could shine today is force India, though problems in qualifying mean that both drivers, particularly Nico Hulkenberg, have their work cut out.
Despite Esteban Gutierrez' "battery pack" issue, Sauber has been looking stronger here, whilst Toro Rosso should take away a few points, Jean-Eric Vergne keen to make a good impression on rival teams still to confirm their 2015 driver line-ups.
Lotus faces another difficult afternoon, and at this point looks unlikely to add to its tally, whilst a strong qualifying performance from Jules Bianchi could, in the right circumstances, see the Frenchman add to the team's tally.
At Caterham, Marcus Ericsson really does need to assert himself over (temporary?) teammate Andre Lotterer today, the German having been a real inspiration this weekend considering the circumstances.
The fact is, today is all about the Mercedes duo. Even in the dry we have witnessed calamities here, so no need for the weather gods to add to the excitement. Yes, Nico and Lewis have known one another since they were kids and were great buddies. However, the fact is that they are ultra-competitive and rivals and the closer they get to the title, the more it becomes within reach, so that rivalry will become more intense.
With the Constructors' Championship almost secured, soon Mercedes will be able to let its two hounds off the leash, until then, and only then, certain rules must be obeyed. The first of these is, 'thou shall not eliminate thine teammate', and at this circuit, particularly on the first lap, such a thing is entirely possible. Nobody want to see the title decided in a first lap moment of madness... rather a last lap gasp as in Brazil all those years ago.
Assuming they get through La Source unscathed, there is the run down the hill to Eau rouge and then the long climb up Kemmel where last year Hamilton was powerless to prevent Vettel nailing him, going on to score the first of that sequence of nine victories which so utterly decimated the opposition.
Admitting yesterday that he wants to slipstream his teammate Hamilton admitted that "strategy will be key" seeing as this is such a long race.
Forty-five minutes before the start there is a brief rain shower wehile, in the distance the sun is shining. Ah, Spa.
By the time pitlane has opened, the sun is shining, the track mostly dry.
The race is likely to feature two pit stops in the normal course of events, if conditions stay dry. This also means that the teams are likely to have a complete stock of slick tyres. There is one clear fastest way to go: start on the soft tyres, change again to the soft on lap 15 and then the medium on lap 29. A one-stop or a three-stop is theoretically possible, but it's not the quickest approach.
However, if the rain resumes...