>>10434691 lb
>how do they know?
NOAA plug real weather data from satellites into a supacomputer that runs a physics simulation based on the rules of thermodynamics, fluid motion etc to produce a prediction/model.
https://en.m.wikipedia.org/wiki/Numerical_weather_prediction
Pretty cool stuff if you're a weather nerd. Like me.
GFS got an upgrade recently and the European's have a very accurate model called ECMWF.
That P-3 that was flying around in the storm was probably taking soundings to help scientistians better predict the path/intensity of the hurricane.