Saturday summary: Severe rain expected.
This morning started with a damp circuit and some tentative running in tricky track conditions. Many drivers decided to wait for improving weather, which didn't arrive. Rather than improve, the heavens opened and Monza was drenched in a heavy downpour from a rapidly-developing thunder cell that brought a complete halt to any sensible activity on the circuit.
Gradually the thunderstorm moved away, allowing the track to dry out slowly during the break between sessions.
Despite the spectacular conditions today, for some time now Saturday has been marked out as the most severe of the three days of unsettled weather during the Italian Grand Prix weekend.
The following forecast is based on the GFS and UK Met Office computer models, as well as all available mainstream and local weather sources.
This evening, showers are expected across northern Italy, with heavy rain arriving during the night. As you can see from the GFS rainfall projection maps, a large swathe of heavy rain is forecast to arrive towards dawn on Saturday.
As we move through the early morning, the rain is expected to to intensify, falling heavily at times. All mainstream and local forecasts are taking this area of wet weather very seriously, with many sites predicting chances of rain between 70 and 100 percent. Other sources such as Weatherbug and Weather Underground are forecasting a 100 percent chance of rain for tomorrow.
So, rain tomorrow would seem certain, but how much rain is expected?
Put simply, Monza is forecast to receive a lot of rain. 3B Meteo forecast between 10 and 20 millimetres in the morning, and between four and ten millimetres of rain in the afternoon. Weather-forecast.com have laid out the totals in a table, with up to 30 millimeters of rain anticipated for the 24 hour period on Saturday.
The heaviest of the rain is expected to fall between 08:00 and 16:00 local time, with the story of tomorrow looking set to be dictated by precisely when, and how much, rain falls.
