**National Digital Forecast Database (NDFD)**

**Experimental Graphic Forecast Displays**

**Product Description Document (PDD)**

**1/31/05**

**Part I - Mission Connection**

a.  [Description of Product]{.underline} - The National Weather
    Service's National Digital Forecast Database (NDFD) Experimental
    Graphic Forecast Displays
    (<http://weather.gov/forecasts/graphical/sectors/index.php>) are
    web-based presentations of digital forecast data originating from
    local Weather Forecast Office (WFO) digital databases and the NDFD
    server. The data are displayed in a mosaic form on national and
    regional scales. Local scale products are not covered under this
    Product Description Document (PDD). For more information on the
    NDFD, please refer to the NDFD Information web site at the following
    URL:
    [[http://www.nws.noaa.gov/ndfd/index.htm]{.underline}](http://www.nws.noaa.gov/ndfd/index.htm).

> Experimental graphic displays for the contiguous United States (CONUS)
> and Puerto Rico include the following nine forecast elements:
>
> -Surface Temperature
>
> -Dew Point
>
> -Weather
>
> -Sky Cover
>
> -Quantitative Precipitation Forecasts (QPF)
>
> -Snow Amount
>
> -Wave Height
>
> -Wind Direction
>
> -Wind Speed
>
> Experimental graphic displays for Hawaii and Guam include the
> following 12 forecast elements:
>
> -Maximum Temperature
>
> -Minimum Temperature
>
> -Probability of Precipitation /PoP12/
>
> -Surface Temperature
>
> -Dew Point
>
> -Weather
>
> -Sky Cover
>
> -Quantitative Precipitation Forecasts (QPF)
>
> -Snow Amount
>
> -Wave Height
>
> -Wind Direction
>
> -Wind Speed
>
> Depending upon the element, forecast time projections will extend out
> to a maximum of 168 hours. Additional data fields having greater
> temporal and spatial resolution will be added as the NDFD matures.

b.  [Purpose]{.underline} - NDFD is a high resolution data set in
    non-displayable form. In support of the mission described in the
    ***National Weather Service Strategic Plan for FY2003 - FY 2008***,
    the NDFD is a "\...national information database and infrastructure
    which can be used by other governmental agencies, the private
    sector, the public, and the global community." Graphic displays of
    these data are primarily required by NWS forecasters needing to view
    a composite of the collective forecast efforts, as well as emergency
    managers who require rapid visual forecast information to help make
    critical decisions. Once these graphic displays are created, they
    must also be made available to the general public. The NDFD graphic
    forecasts fulfill additional NWS objectives for improving the
    accessibility and availability of weather information to the public.
    Future graphic mosaic displays will be developed in accordance with
    growing user needs.

c\. [Intended Audience]{.underline} - The NWS graphic forecasts are
intended for government emergency managers, academia, businesses, and
anyone in the general public who needs to view the content within the
NWS digital forecast databases. While the data are available in digital
form, many NWS customers cannot interpret or use these digital data
unaided. For those who cannot, a graphic presentation is the most
efficient means to communicate the large amount of information
originating from NWS WFOs.

d\. [Presentation Method]{.underline} - The data are presented as
web-based graphic images. The NDFD National mosaic provides weather
forecast information for the entire contiguous United States (CONUS) and
U.S. territories outside the contiguous United States (OCONUS) including
Hawaii, Guam, and Puerto Rico/Virgin Islands. In the future,
geographical data sectors will also be available for Alaska.

> The graphic forecast displays follow a standard format prescribed by
> the NWS to best meet the needs of its customers and partners. When
> selected by the user (via a mouse click on the national mosaic),
> regional mosaics provide images for 16 predefined and slightly
> overlapping geographic sectors throughout the CONUS, as depicted at
> the following URL: <http://www.weather.gov/ndfd/coverage.htm>. Three
> OCONUS sectors are also available for Hawaii, Guam, and Puerto
> Rico/Virgin Islands. For the CONUS, an additional mouse click will
> drill down to graphics for each state. One final mouse click will zoom
> to individual WFO County Warning and Forecast areas. Most OCONUS
> sectors also have limited zoom capability. For each geographic level
> of display, the user may select the weather element and time period to
> display, and create animations of the images.

e\. [Feedback Mechanism]{.underline} - We are always seeking to improve
our products based on user feedback. Please submit your comments on
these experimental elements by completing our brief [[experimental
product
survey]{.underline}](http://weather.gov/survey/nws-survey.php?code=egf).
Comments may also be submitted by clicking on the "Survey/Comments"
links on the experimental product web pages. For general questions
regarding the National Digital Forecast Database, please email:
***nws.ndfd@noaa.gov***

**Part II - Technical Description**

a\. [Format & Science Basis]{.underline} - The NDFD forecast element
definitions and technical information (e.g., temporal and spatial
resolutions of the graphics, and geographic coverage) may be found on
the NDFD technical page at the following URL:

> <http://www.nws.noaa.gov/ndfd/technical.htm>

b\. [Product Availability]{.underline} - The NDFD web-based graphic
mosaics are continuously by accessing the main National Weather Service
homepage, [www.weather.gov](http://www.weather.gov/), and clicking on
the "Graphical Forecasts" tab, or directly at the following URL:

> <http://weather.gov/forecasts/graphical/sectors/index.php>

Forecast grids are revised at the local WFOs on an event-driven basis.
The revised grids are uploaded to the NDFD server and new graphic
mosaics are generated at the top of each hour. At a minimum, revised
mosaics will be refreshed daily no later than 1800 Coordinated Universal
Time (UTC).

c\. [Other Details]{.underline} -

1.  National Weather Service Instruction (NWSI) 10-506, Digital Data
    Products/Services Specification provides detailed information on
    both experimental and official elements in NDFD.

2.  Experimental graphical elements are differentiated from NWS official
    elements by the "experimental" label found on the individual
    graphics.

3.  Experimental graphical elements are evaluated regularly on
    timeliness, completeness, spatial consistency, accuracy, and other
    subjective criteria. When they meet the guidelines established by
    the NWS, they are declared "official" and are no longer covered by
    this PDD for experimental elements.

4.  Graphic Forecast displays for Temperature, Dew Point, and Weather
    are scheduled to become official elements on March 15, 2005.