The National Collegiate Forecasting Contest, Page 2 of 8

In the National Collegiate Weather Forecasting Contest, you will make 24-hour forecasts of the maximum and minimum temperatures and precipitation amount. The city will change every two weeks, and the period of record is 06Z that night to 06Z the following night.

What's a 06Z? Greenwich time, or Universal Time, or Zulu time, or Z time, properly abbreviated UTC, are all names for the same time convention. They represent the time in Greenwich, England. Meteorologists use Greenwich time for all their observations because it provides a standard reference time.

In the continental United States, we have Pacific Standard Time, Mountain Standard Time, Central Standard Time, and Eastern Standard Time (not to mention all the daylight savings times). The time in each time zone is one hour later than the time in the time zone immediately to its west, and one hour earlier than the time in the time zone immediately to its east. Now, if you go across the Atlantic Ocean, you pick up another five hours from Eastern Standard Time by the time you get to the Greenwich Meridian (0 degrees).If you've never seen a map of the world's time zones, check out this map to see how it works. (size: 216K) , or visit an interactive time zone site.

Greenwich time is like military time. There's no AM or PM; instead, it starts with 0000Z (for midnight), advances forward from there (for example, 6AM would be 0600Z), hits noon at 1200Z, continues to 6PM at 1800Z, and reaches 2359Z just before the following midnight. Often, the minutes digits are omitted ; thus, 14Z and 1400Z are identical. (14 minutes past midnight would be written 0014Z.)

Questions or Comments

Technical: E-mail John Fulton < jdfult@nimbus.met.tamu.edu >
Scientific: E-mail Dr. John Nielsen-Gammon. < nielsen@ariel.met.tamu.edu >