Can someone please explain the "Z's"

tropicstorm · #1 Postby **tropicstorm** » Wed Sep 29, 2004 6:45 pm

What is meant by the 0Z, OOZ, 3Z, 36Z and so on. I've seen these references made to model forecasts. Is this a time frame, a nautical position, an atmospheric condition or something else? Please explain. Thanks.

#2 Postby **tronbunny** » Wed Sep 29, 2004 6:50 pm

Z is for "Zulu"

UTC stands for Universal Time Coordinated, what used to be called Greenwich Mean Time (GMT) and Zulu Time (Z). This is the time at the Prime Meridian (0° Longitude) given in hours and minutes on a 24 hour clock. For example, 1350 UTC is 13 hours and 50 minutes after midnight or 1:50 PM at the Prime Meridian.
The Royal Naval Observatory at Greenwich, England (near 0° Longitude) was where naval chronometers (clocks) were set, a critical instrument for calculating longitude. This is why GMT became the standard for world time. Meteorologists have used UTC or GMT times for over a century to ensure that observations taken around the globe are taken simultaneously.

http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqA.html

tropicstorm · #3 Postby **tropicstorm** » Wed Sep 29, 2004 7:30 pm

Thank you tronbunny - a very informative & well written explanation. I do understand the relative GMT to all longitudinal world time but, I'm still a bit hazy on this. For example, what is the time difference between 0Z and 00Z? Is one of these initializing a midnight UTC to start a new 24 hour world clock? What is different bewtween 0 and 00? Also, if I see a reference to the 36Z NOGAPS - is that the time of 12:36 a.m. UTC? What is meant by 3Z - is this 12:03 a.m. or 3:00 a.m.? Still a bit confused.

Website · #4 Postby **Brent** » Wed Sep 29, 2004 7:36 pm

12z would be 12pm
0z would be 12am(Midnight)
6z would be 6am
18z would be 6pm

etc... etc... etc.

0z and 00z are the same time.

Now the conversion is for Zulu time, subtract 4 hours to get Eastern Daylight Time.

Stormsfury · #5 Postby **Stormsfury** » Wed Sep 29, 2004 7:42 pm

Brent wrote:12z would be 12pm
0z would be 12am(Midnight)
6z would be 6am
18z would be 6pm

etc... etc... etc.

0z and 00z are the same time.

Now the conversion is for Zulu time, subtract 4 hours to get Eastern Daylight Time.

Correct ... and subtract 5 hours for Eastern Standard Time ...

I was working on a post when something popped up and ended up locking up my PC ... :grr:

Website · #6 Postby **Brent** » Wed Sep 29, 2004 7:53 pm

Stormsfury wrote:I was working on a post when something popped up and ended up locking up my PC ...

I've been having the same problem. I hate spyware. It's been working a lot better in the last couple of days though.

Guest · #7 Postby **Guest** » Wed Sep 29, 2004 9:15 pm

Its happened here to.

isobar · #8 Postby **isobar** » Thu Sep 30, 2004 11:56 am

tropicstorm wrote: Also, if I see a reference to the 36Z NOGAPS - is that the time of 12:36 a.m. UTC?

The 36Z refers to the hrs from the time of the update. For example, NOGAPS runs every 12 hrs. Here's the last run today at 00Z for 36 hrs out.

http://bricker.met.psu.edu/trop-cgi/nogapstc2.cgi?time=2004093000&field=Sea+Level+Pressure&hour=036hr

#9 Postby **drudd1** » Thu Sep 30, 2004 12:05 pm

In my case, Z refers to what I caught last night with power and AC, lot's of ZZZZs. Smack me, I know I'm bad, but I couldn't resist that. Sorry.

#10 Postby **WeatherEmperor** » Thu Sep 30, 2004 12:44 pm

Brent wrote:
Stormsfury wrote:I was working on a post when something popped up and ended up locking up my PC ...

I've been having the same problem. I hate spyware. It's been working a lot better in the last couple of days though.

That is why I use Netscape Navigator. It has build in anti-spyware and auto-popup blockers. Much better and safer then Internet Explorer in my opinion

#11 Postby **PurdueWx80** » Thu Sep 30, 2004 12:46 pm

There is no such thing as 36Z...there are only 24 hours in a day.

Can someone please explain the "Z's"

Can someone please explain the "Z's"

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