The elements are leading weather forecasters – be it Meteo France at the circuit, professional meteorologists or experienced amateurs – on a wild goose chase as everyone attempts to pin down exactly when and how much rain will fall at Interlagos during qualifying and Sunday’s Brazilian Grand Prix.
Looking quickly at today, conditions were fine, dry and sunny for both 90-minute sessions. Lewis Hamilton looked good out there once again, and while the timesheet was extremely close between the leading contenders this morning, the Briton seemed to just have that little extra in the afternoon. Ambient temperature rose to 33 Celsius, while down on the asphalt it got very close to the reaching the 50 degree barrier.
However, there is a change on the horizon – and it is going to come sooner than we thought. This now has a tremendous bearing on the outcome of the weekend, so first of all I will point you towards this link, showing the latest satellite image for south America and where the cold front is currently positioned.
As you can see, the front is moving north-eastwards at a faster rate, meaning that showers will arrive earlier, but also that the whole thing is likely to clear the area quicker than the models suggested this time yesterday.
So, we go into Saturday with a dry start and clouds moving into the region before final practice. The 60-minute session will remain dry so we will get through that without too much trouble, but with decreasing amounts of sunshine track temperature values will suffer. It will turn overcast late tomorrow morning and there is a renewed threat of rain for qualifying. Showers are possible any time after midday local time. For reference, the knockout session begins at 14:00 BRST.
A bi-product of all this is that temperatures will decrease earlier and we are now looking at a maximum of 27 or 28 Celsius during qualifying. Showers are expected throughout the afternoon and the heaviest rainfall is forecast for Saturday night. This is no bad thing if you would prefer a potentially jumbled grid, but the trade-off is that you won’t get the deluge conditions during the grand prix.
Further showers will follow on behind during the overnight period and into Sunday morning, but all the while, this front will be moving through. There is still a threat of mainly light showers and sprinkles as we go through the day, but the risk of a flooded circuit and all the associated chaos is no longer on the table, based on the model charts over the last 12-18 hours. By light showers I mean something akin to the 2008 pre-race sprinkle that had Mr. Ecclestone and others running for cover, resulting in a delayed start and those wonderful early laps.
Air temperature on race day will be down to a maximum of 22 or 23 degrees, as the cold air behind the front takes hold over the Sao Paulo area. Certainly, we have seen the best of the weather and things are set to go downhill after midnight tonight.
The irony of all this is that in our sport where speed is paramount, it is in fact the speed and evolution of a weather system that could determine whether Vettel gets a trouble-free afternoon or not.
So yes, this one is proving to be a real challenge. Above, I have outlined the expected scenario from today’s charts. Now we wait and see what tomorrow brings. I will be around on Twitter providing as much real-time information as I can via the latest satellite images and rain radars. Then, once qualifying has concluded, I will be back with the final forecast of the 2012 campaign, looking ahead in detail to Sunday’s weather.