Concerns surrounding the weather for this weekend's Malaysian Grand Prix at Sepang are mounting, with
forecasts calling for a high chance of rain for Sunday's 56-lap race.
The early build-up to the second round of the 2009 championship has already featured an intense storm. On Monday afternoon, the clouds gathered around the circuit and set off a large thunderstorm, which produced an impressive 76 millimetres of rain between 4pm and 7:30pm. The track quickly became undriveable, with flash-flooding noted on parts of the circuit.
Since then, the weather had been rather quiet ... until this afternoon. Tuesday was completely dry - although very hot - and on Wednesday light rain only began to fall at 10 o'clock in the evening, following another dry day.
Today, the recent dry run since Monday continued as the drivers arrived on the scene to join up with their respective teams, but the sunny morning soon evaporated. Menacing clouds began to build as the safety and medical cars conducted their track test, and - predictably - another thunderstorm ensued shortly afterwards. This evening should clear up somewhat following the storm, leaving a dry night and temperatures dipping slightly to 24 degrees.
Several weather forecast models are predicting a dry morning on Friday with mainly sunny skies. Later, for the second practice session in the early afternoon, we should see cloud cover build over the Sepang F1 Circuit, but conditions should remain dry, with any rain occurring towards the evening.
Changes to the schedule for Malaysia this year, to benefit European television audiences, mean the track action takes place later in the day on Saturday and Sunday. The final practice session on Saturday is expected to run in dry, but mostly cloudy conditions.
However, the rain threat will be intensifying throughout the afternoon, as a rise in convective potential energy in the atmosphere brings in more cloud, and therefore more volatile atmospheric conditions that could be conducive to a thunderstorm. Qualifying, at best, is set to run in dry but overcast conditions, but with a 70 percent chance of a thundery shower predicted it would be no surprise to see the knock-out session affected in some way.
Late on Saturday evening, the thundery threat will diminish for a time, leading us into a repeat forecast for race day - but with more potential for storms.
The Sunday storm risk is currently predicted at 80 percent, as convective energy increases still further from the Saturday values. Race morning will dawn dry and fairly bright, but again, clouds will bubble up in the area quickly, with a significant storm risk by late afternoon.
The forecast is undoubtedly a concern, given the natural limits of daylight in the early evening. Daylight is scheduled to end at approximately eight o'clock, giving Formula 1 three hours in a thundery, volatile atmosphere to conduct the 56-lap grand prix.