Weather Studies
Website User's Guide


Getting Started

Weather Products


Click on the desired item for more information.

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Weather Studies Maps & Links

The Website lists Weather Studies products generally by data type. The table below gives a brief overview of the data types.

Data Type Description
Surface -
Maps and text displaying surface weather data (e.g. fronts, pressure, data from across individual states)
Radar - Maps displaying radar information (e.g. radar, radar and fronts)
Satellite - Current and archived visible, infrared, and water vapor imagery
Upper Air - Maps and text displaying upper air weather data (e.g. St�ve, 500 mb)
Watches, Warnings, Advisories and Forecasts - Severe weather alerts and maps of future weather conditions over the next 48 hours
Extras - Blank maps for plotting use, station locations, explanations of symbols

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Learning Files

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Several miscellaneous materials are available. Blank plotting maps, meteorological graphs, additional weather information sources, and additional notes are given here.

Updating of Weather Products

The following is a list of available data and map products:

  1. North American surface weather observations - for approximately 200 stations, updated hourly.
  2. Upper air observations - updated twice daily (these represent atmospheric conditions above the Earth's surface at 0000Z and 1200Z each day).
  3. Radar data - updated hourly (conditions represent a national view at 35 minutes after the hour).
  4. Satellite data - updated hourly. (Visible images are only delivered during the daylight period.)
  5. General surface map features - including fronts and low and high pressure centers, updated every three hours (these features represent conditions at 00, 03, 06, 09, 12, 15, 18, and 21Z).
  6. Forecast data - updated twice daily, based on computer model output from 00Z and 12Z data inputs.
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Time Displayed on Weather Studies Products

You may have noticed that on all our products, a time like 10Z 02 JAN 2004 is displayed. What is Z time?

In order for meteorologists to communicate about data, it is necessary to have a global reference time for all meteorological data. This reference time is commonly referred to by the following names: Z time (Zulu), UTC (Universal Coordinated Time), or GMT (Greenwich Mean Time). The value represents the time zone of Greenwich, England, UK. This time will always be ahead of US time zones.

To convert the value to your local time, you need to know the time of year and how many hours different your time is from Greenwich time. For example, a map may display a time and date of 18Z 01 JAN 2004. What time would this be locally in Chicago? First think of 18Z as "military time" and then translate it to a clock value in either am or pm. So 18Z becomes 6:00 pm. To adjust for the time of year, we know that Chicago is in the Central Standard Time zone in winter, so using the table below,

Time Zone Standard
Atlantic 4 NA
Eastern 5 4
Central 6 5
Mountain 7 6
Pacific 8 7
Alaska 9 8
Hawaii 10 NA
Aleutian 10 9
Samoa 11 NA

we know that Greenwich is 6 hours ahead of Chicago. Thus for Chicago local time, subtract 6 hours from 6:00 pm and you have 12:00 noon local time.

For a view of world time zones, go to

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