ChrisVJ - Aerocat is spot on. Our data also stops at 50 degrees. As for numbers, at our main base we can normally lift a full load from any runway from any intersection. On one particular runway we have 3,800 metres of tarmac. At 50 degrees Celsius we can only 43,700 kgs. At 46 degrees we can lift 45,000. This means that each degree at this temperature is 325 kgs or 3.5 passengers with bags or just over 10 minutes of fuel.
That was a well written article though. Clearly that reporter doesn't have a future, he'll have to reduce his accuracy and standards if he expects to get on!