u/f1sefiri

EDIT: I forgot to update the Fahrenheit conversion for the temperature on Sunday, it should read 79º to 84ºF.

F1 is finally back, and I'm back with a weather forecast, which unfortunately means some interesting weather is expected this weekend. Now that we're within 48 hours of FP1, we can take an early look at the forecast, which I'm calling a "preview".

Friday and Saturday should be fine, but there is a real threat of heavy rainfall and/or thunderstorms at least on and off on Sunday. We are still five days out, and so a lot can and will change, but we are currently looking at a growing model consensus at a cold front bringing stormy weather on Sunday. The ECMWF/European model is in particular intense, showing a heavy thunderstorm dropping nearly 1 inch (2.5 cm) of rainfall in the three-hour span that the race falls into. Other models are thankfully less intense.

We are not yet in range of the high-resolution mesoscale models, which can actually model thunderstorms, but we should be by Friday. I'll be back on Friday morning with a full weekend forecast update, and possibly again on Sunday morning for a race-specific outlook.

Finally, I hate to mention this coming off of a month break and two cancellations, but I need to note that most U.S. sporting events are required by contract with workers, the event space, and local government to have plans for lightning in place. I could not find the specific policy for Hard Rock Stadium, but the Miami GP website lists the following:
"When lightning is detected in close proximity of the Miami International Autodrome, the public address system will inform guests where to seek shelter. The event will be suspended if there is an imminent threat."

My understanding is many outdoor U.S. sporting events have a "lightning clock", where any lightning strike or thunder heard within a certain radius of the location (ex: 10 miles) immediately starts a 30 minute countdown, during which the event is suspended and fans/employees are instructed to seek shelter. Every subsequent thunder heard resets that timer, until 30 minutes have passed since the last thunder was heard, after which the event may resume. This does not give a lot of leeway for F1, especially if the storms are slow-moving as they likely will be with a cold front transitioning to stationary. The best hope is that the front and any associated storms fully clear the track by the afternoon, or that they remain heavy showers with no lightning.