Sometimes you see meteorological imagery and just say wow.
Today a huge low center extends over much of the northeast Pacific, while an impressive plume of moisture–an atmospheric river– stretches southwest-northeast towards the California coast.
The infrared satellite image this morning shows the situation, with the white areas indicating higher clouds.
Want to be impressed even more? Here is the water-vapor satellite image at the same time, viewing the emission of water vapor to space. Scary for northern California!
For reference, here is the sea-level pressure analysis at the same time, with low-level temperatures and winds also shown. Perhaps the largest low-pressure center I can remember spreading over a vast area. With warm air from the southwest on the southern side (orange colors). That is the atmospheric river.
To really hit that home, below is a map for the same time (this morning) of a potent diagnostic of atmospheric rivers, integrated vapor transport, IVT. This describes how much water vapor is being pushed around by the wind.
Blue colors show very high values in the core of the atmospheric river.
Substantial precipitation will fall today and tomorrow in California and Oregon from this atmospheric river (see forecast below). Northern California has been the most anomalously dry part of the Golden State. No longer.