Before AR conditions from the first AR completely dissipate, a second AR associated with a surface low-pressure system is forecast to bring a stronger pulse of IVT > 600 kg/ms to the same areas, resulting in AR 2 conditions (based on the Ralph et al. 2019 AR Scale)
The third and strongest AR is forecast to make landfall along the coast of Northern California with IVT exceeding 750 kg/ms resulting in AR 3/AR 4 conditions in the region, although considerable uncertainty remains in the exact timing, intensity, duration, and position of this system
Não admira que tenham dado categorias aos rios atmosféricos. Para os profissionais, ao menos assim a missão não é tão entediante.
Já para o público em geral, a informação não vale nada.