CHARLOTTE, NC (WBTV) - Have you ever looked at a weather chart and noticed something called Z-Time? That's Zulu Time or Coordinated Universal Time (UTC).
Look at the top of this map. It says FCST VALID SUN 04/24/16. That means the 0 hour forecast is valid Sunday morning, the 24th at 12UTC or 8 a.m. EDT.
There is something called synoptic meteorology where all measurements are taken at the same time, basically taking a snapshot of the state of the atmosphere. In order for all meteorological measurements to be made at the same time all across the world, this system is used.
Here's how it works.
The reference point is 0° longitude at Greenwich, England. It's based on a world-wide 24-hour clock. Since the earth rotates 360° each day, the sun is moving 15° each hour. That equals 24 time zones. Z-Time goes from 0Z to 23Z. Then it starts over on the next day.
What does it means for us in North Carolina in the Eastern Time Zone?
0Z Sunday is actually 7 p.m. on Saturday. Since we're in Daylight Saving time, 0Z Sunday is 8 p.m. Saturday. You can remember it because the Prime Meridian (in England) is always ahead of us. They start the clock on a new day while we're still in the old day.
0Z Sunday = 7 p.m. EST or 8p.m. EDT Saturday
6Z Sunday = 1 a.m. EST or 2 a.m. EDT Sunday
12Z Sunday = 7 a.m. EST or 8 a.m. EDT Sunday
So there you go! Throw that out at the water cooler tomorrow morning.