The 2013 Formula 1 season returns to Europe after four flyaway races to open the championship. Sebastian Vettel, Red Bull Racing and the rest of the grid have completed visits to Australia, Malaysia, China and Bahrain and return to familiar territory this weekend, with the Spanish Grand Prix at the Circuit de Cataluña.
As usual, the race weekend starts with two practice sessions on Friday, followed by a third on Saturday morning and then the qualifying hour. The race will be on Sunday.
The defending champion here is William's Pastor Maldonado, who secured a brilliant maiden win here last season. However, unless we have a similarly epic drive from the Venezuelan, we are likely to see one of the usual suspects on the top step of the podium on Sunday afternoon.
Where to Watch Live
Live coverage of the first practice session starts at 8.45am BST on Sky F1. Live coverage of the second practice session starts at 12.45pm BST on Sky F1. . Real time text updates, for both sessions, are available under the Live Timing section on the sport's official Web site.
Defending world champion Vettel has a 10 point lead at the top of the table after four rounds. The German has former champion Kimi Raikkonen behind him, with two other former champions in Lewis Hamilton of Mercedes and Fernando Alonso of Ferrari in third and fourth. Vettel's team mate, Mark Webber, rounds out the top five.
Alonso will be particularly keen to make up ground in the title race this season, after mechanical issues forced the Spaniard to settle for eighth in Bahrain. The Ferrari ace faces a 30 point gap to Vettel, which is big but not insurmountable.
Hamilton, in his debut season with the Mercedes works team, seems to have made the right decision so far; he quit McLaren-Mercedes, with whom he won the 2008 championship, last year.
Significant attention will be on Raikkonen; the Finn won the 2007 championship with Ferrari and seems to have rediscovered his winning form. He won the season-opening Australian Grand Prix and finished second in China and Bahrain.
In the race for the constructors' title, Red Bull are edging away from Lotus-Renault. The Milton-Keynes team have 109 points to Lotus' 93. Ferrari and Mercedes are third and fourth but are already 32 and 45 points behind. Force India-Mercedes have fifth ahead of McLaren.
The 4.65km circuit held its first race in 1991 and has since become something of a favourite for drivers and teams. The circuit is often home to pre-season test sessions and therefore holds few surprises for most drivers. As a result of familiarity with the layout, most teams tend to bring significant aerodynamic and structural modifications to this race.
"The whole Barcelona circuit is interesting as it includes all types of corners and offers a really good mix, but my favourite part is still the first sector, because it has really quick corners," Vettel explains in the build-up to the race weekend. The German's highlights include the demanding Turn Three, which is a long right-hander that demands control of speed, braking and track position.
However, as Raikkonen points out, familiarity with the layout does not mean teams will have an easy weekend. Changing weather conditions will need to be monitored. Equally importantly, drivers must be careful not to overheat tyres; something that is easy to do given the high-speed sections in the first two sectors.
Raikkonen's team mate, Romain Grosjean, reveals: "Tyre management will still be the key area for a good performance in the race. In Barcelona it will be important to qualify well as it will be much harder to overtake than in Bahrain."
The Lotus cars will likely sport a number of modifications, including "a new front wing endplate detailing, new aero around the rear drums, modifications to the diffuser and a different top rear wing", according to technical director James Allison.
The Circuit de Cataluña has one major aspect that will demand attention from the teams - engine use. On average, drivers spend 55% of a lap at full throttle, which is quite a considerable amount. The good news is this allows the KERS system to be used twice in a lap, which should counteract overtaking concerns.
However, the flowing nature of the track, particularly the second, infield, sector, means power delivery from the engine has to be near perfect. The cars will go from nearly 250km/h at the approach of Turn Five to 145km/h at Turn Seven and then back up to 230km/h for Turn Nine. Power delivery will be the focus again from Turn 13 through to the end of the lap, and with the long start-finish straight, it is imperative that cars get an excellent run out of the final corner.
Wind conditions could also play a part in quick times, as will the balance between mechanical grip and aerodynamic grip. Cars will look to run stiffer front ends, to help turn in to high-speed corners, but will rely on aero grip from the rear wings to keep the rear in check. Too much front end grip could lead to oversteer, while too little and the car will simply not turn in to a corner.
The Italian company's motorsport director, Paul Hembery, has confirmed that a revised version of the hard compound will be available this weekend. Pirelli will offer P Zero Orange (hard) and P Zero White (medium) compounds but will also give teams one extra set of experimental hard tyres, for the practice sessions only.
"This new tyre gives us a wider working temperature window - although it delivers a little bit less in terms of pure performance - but it should allow the teams to envisage an even wider variety of race strategies than before in combination with the other compounds," Hembery explained.
Weather forecasts predict significantly less rainfall than original estimates. There is still likely to be some rain, particularly early in the day, but it should clear up by the time the two practice sessions start. Temperatures will settle at about 20C, with some minor fluctuation through the day. Cloud cover has also dropped from earlier estimates, which suggested 90% coverage. For now, that will probably drop to 60% by mid-morning and we should see a sunny first practice session.
The second session starts at 2pm local time. The temperatures should remain constant and the sun should continue to shine. However, forecasts do caution teams there may be a spot of rain in the evening.
Finally, the wind factor. High winds can affect car handling at this circuit, particularly as the turn into the first corner and negotiate the infield sector. And as in the Bahrain Grand Prix, teams will face troublesome winds, with speeds up to 17km/h. This will likely be in the afternoon session; morning session wind speeds are estimated at six to eight km/h.