National Weather Service United States Department of Commerce

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 >

 

Pictures from around western Colorado and eastern Utah
What is "Z" Time?

Since weather observations and forecasts are provided around the globe, it is important to understand when each piece of data is valid for. To overcome the problem of numerous time zones, it was internationally agreed upon that weather time stamps would be based on the Prime Meridian, or Greenwich Mean Time (GMT).

Other names for GMT include Universal Time Coordinated (UTC) or "Z" Time.
In the Mountain Time Zone:

Z = MST + 7 hours
Z = MDT + 6 hours
or
MST = Z - 7 hours
MDT = Z - 6 hours


examples: 11 am MST = 1800Z (6:00 pm GMT)
or
1800 MDT (6:00 pm) = 0000Z (Midnight the next day GMT)

Map of World Time Zones