Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

Upper Air Charts

Here is a series of upper air maps from 20 June 1957 at 6 am CST (12 UTC), and 6PM CST (00 UTC) on 20 June 1957 (around the time of the tornado). The upper air pattern was characterized by a southwest flow aloft, and moisture returning into the northern plains. Images courtesy of Jonathan Finch (NWS).

6 AM CST (12 UTC) 20 JUNE 1957