It isn't as simple as that. Here's what we wrote about it on a recent Facebook post:
The Flyable Conditions overlay uses a new short-term weather forecasting technology performing fusion of data streams from a number of near-realtime information sources, including satellite imagery (EUMETSAT), ground observations, and traditional numerical weather prediction forecasts. The data isn't currently available anywhere else.
I understand that although there is a NWP model used, it doesn't play a big part in this forecast.