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Home > NDFD > NDFD REST Service

National Digital Forecast Database (NDFD)
REST
Web Service


NOAA's National Weather Service offers several XML services
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  1. What is the NDFD REST Service?
  2. Why provide an NDFD REST service?
  3. How often is NDFD REST Service updated?
  4. How is NDFD Data generated?
  5. What data does the NDFD data contain?
  6. How Do You Use the Web Service?
  7. What if I need lots of NDFD data or find the web service too slow?
  8. What if I prefer to use SOAP or a WFS to access NDFD web services?
  9. NWS XML Services Change Notices

What is the NDFD REST Service?

National Digital Forecast Database (NDFD) REST service provides the public, government agencies, and commercial enterprises with data from the National Weather Service’s (NWS) digital forecast database.   This service, which is defined in a Service Description Document, provides NWS customers and partners the ability to retrieve NDFD data over the internet that is encoded in XML.

The XML dialect used is called Digital Weather Markup Language (DWML) and its schema can be found at the following link:

http://www.weather.gov/forecasts/xml/DWMLgen/schema/DWML.xsd

The schema defines the XML language’s vocabulary (available tags and attributes) and syntax (expected order of tags).   Knowing how DWML is constructed, users can write programs to process the XML document to get at the data it contains.

To see a sample Digital Weather Markup Language document that conforms to the DWML schema, click on any of the following links:

http://www.weather.gov/forecasts/xml/DWMLgen/schema/latest_DWML.txt
http://www.weather.gov/forecasts/xml/DWMLgen/schema/latest_DWML_glance.txt
http://www.weather.gov/forecasts/xml/DWMLgen/schema/latest_DWMLByDay24hr.txt
http://www.weather.gov/forecasts/xml/DWMLgen/schema/latest_DWMLByDay12hr.txt

Why provide an NDFD REST service?

The National Weather Service is striving to serve society’s needs for weather information by evolving its services from a text-based paradigm to one based on making NWS information available quickly, efficiently, and in convenient and understandable forms.   The NDFD is one example of this transformation.   NDFD REST takes yet another step towards a digital services era by making NDFD data available for computer to computer transfer and processing.   NWS customers and partners can then enhance the value of NDFD data through the creation of value added products.

You can provide comments on this web service from the following page.

http://www.weather.gov/feedback.php

How often is NDFD data updated?

The NDFD data available via the REST service is updated no more than hourly. As a result, we request developers using this REST service only make a request for a specific point no more than once an hour. The database is currently updated by 45 minutes after the hour.

You can interact with the REST service by visiting the following URLs:

http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXML.htm http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserByDay.htm

By clicking the “submit” button on the above web pages, a script is executed to request and retrieve DWML-encoded NDFD data.

What data does the NDFD contain?

NDFD XML contains forecasts for any combination of the following meteorological parameters:

http://www.weather.gov/ndfd/technical.htm#elements

For additional information on NDFD parameter definitions and available time projection, please see the NDFD technical page.

These NDFD parameters can be retrieved in their unsummarized form using the ndfdXMLclient.php interface, or summarized over either 24- or 12-hourly periods using the ndfdBrowserClientByDay.php interface. See the section below titled "How Do You Use the Web Service?" for more details on these two methods of accessing the service.

In addition to its meteorological content, the NDFD REST service response contains meta data.   A description of the meta data and data XML tags and attributes can be found in the Digital Weather Markup Language Specification [PDF] [HTML] [DOC]

How Do You Use the Web Service?

The first step to using the web service is to create a RESTful client.   The client submits an HTTP request containing a query string that holds the input expected by the service.   See the tables below for required user supplied input:

ndfdXMLclient.php Interface

    Single Point Unsummarized Data: Returns DWML-encoded NDFD data for a point

    lat 39.0000 The WGS84 latitude of the point for which you want NDFD data.   North latitude is positive.
    lon -77.0000 The WGS84 longitude of the point for which you want NDFD data.   West longitude is negative.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?lat=38.99&lon=-77.01&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-20T00:00:00&maxt=maxt&mint=mint

    Multiple Point Unsummarized Data: Returns DWML-encoded NDFD data for a list of points

    listLatLon 38.99,-77.02 39.70,-104.80 List of WGS84 latitude and longitude pairs for the points for which you want NDFD data.   Each point's latitude and longitude value is seperated by a comma. Each pair (one latitude and longitude value) is separated by a space. Number of points requested can not exceed 200.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?listLatLon=38.99,-77.02 39.70,-104.80 47.6,-122.30&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-20T00:00:00&maxt=maxt&mint=mint

    Unsummarized Data for a Subgrid: Returns DWML-encoded NDFD data for a subgrid defined by a lower left and upper right point

    lat1 33.8835 The WGS84 latitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    lon1 -80.0679 The WGS84 longitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    lat2 33.8835 The WGS84 latitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    lon2 -80.0679 The WGS84 longitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    resolutionSub 20.0 The default resolution for NDFD data is typically 5km. However, users can request latitude and longitude values for resolutions greater ( 10km, 15km, 20km, etc.) than the native resolution so as to reduce the number of points returned.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?lat1=35.00&lon1=-82.00&lat2=35.5&lon2=-81.50&resolutionSub=20.0&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-21T00:00:00&maxt=maxt&mint=mint

    A List of NDFD Points for a Subgrid: Returns the WGS84 latitude and longitude values of all the NDFD grid points within a rectangular subgrid as defined by points at the lower left and upper right corners of the rectangle. The returned list of points is suitable for use in inputs listLatLon and gmlListLatLon. NOTE: The subgrid locations will only form a rectangle when viewed in the NDFD projection applicable to the grid.

    listLat1 33.8835 The WGS84 latitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    listLon1 -80.0679 The WGS84 longitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    listLat2 33.8835 The WGS84 latitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    listLon2 -80.0679 The WGS84 longitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    resolutionList 20.0 The default resolution for NDFD data is typically 5km. However, users can request latitude and longitude values for resolutions greater ( 10km, 15km, 20km, etc.) than the native resolution so as to reduce the number of points returned.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?listLat1=35.00&listLon1=-82.00&listLat2=35.5&listLon2=-81.50&resolutionList=20.0

    Unsummarized Data for a Line: Returns DWML-encoded NDFD data for a line of points defined by the two end point

    endPoint1Lat 39.0000 The WGS84 latitude of the first end point of the line for which you want NDFD grid points.   North latitude is positive.
    endPoint1Lon -77.0000 The WGS84 longitude of the first end point of the line for which you want NDFD grid points.   West longitude is negative.
    endPoint2Lat 39.0000 The WGS84 latitude of the second end point of the line for which you want NDFD grid points.   North latitude is positive.
    endPoint2Lon -77.0000 The WGS84 longitude of the second end point of the line for which you want NDFD grid points.   West longitude is negative.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?endPoint1Lat=38.99&endPoint1Lon=-77.01&endPoint2Lat=39.99&endPoint2Lon=-78.01&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-21T00:00:00&maxt=maxt&mint=mint

    Unsummarized Data for One or More Zipcodes: Returns DWML-encoded NDFD data for one or more zip codes (50 United States and Puerto Rico). The returned list of points is suitable for use in inputs listLatLon and gmlListLatLon.

    zipCodeList 20910 The zip code of the area for which you want NDFD grid points.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?zipCodeList=20910+25414&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-21T00:00:00&maxt=maxt&mint=mint

    Unsummarized Data for a Subgrid Defined by a Center Point: Returns DWML-encoded NDFD data for a rectangle defined by a center point and distances in the latitudinal and longitudinal directions.

    centerPointLat 39.0000 The WGS84 latitude of the center or the rectangle for which you want NDFD grid points.   North latitude is positive.
    centerPointLon -77.0000 The WGS84 longitude of the center or the rectangle for which you want NDFD grid points.   West longitude is negative.
    distanceLat 50.0 The distance from the center point in the latitudinal direction to the rectangle's East/West oriented sides.
    distanceLon 50.0 The distance from the center point in the longitudinal direction to the rectangle's North/South oriented side.
    resolutionSquare 20.0 The default resolution for NDFD data is typically 5km. However, users can request latitude and longitude values for resolutions greater ( 10km, 15km, 20km, etc.) than the native resolution so as to reduce the number of points returned.
    product time-series There are two products.   The “time-series” product returns all data between the start and end times for the selected weather parameters.   The “glance” product returns all data between the start and end times for the parameters maxt, mint, sky, wx, and icons
    begin 2004-04-27T12:00 The beginning time for which you want NDFD data.   If the string is empty, the start time is assumed to be the earliest available time in the database.
    end 2004-04-30T12:00 The ending time for which you want NDFD data.   If the string is empty, the end time is assumed to be the last available time in the database.
    One or more ndfd elements maxt=maxt&mint=mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?centerPointLat=38.0&centerPointLon=-97.4&distanceLat=50.0&distanceLon=50.0&resolutionSquare=20.0&product=time-series&begin=2004-01-01T00:00:00&end=2013-04-21T00:00:00&maxt=maxt&mint=mint

    Unsummarized Data for a Single Time Encoded in dwGML: Returns Digital Weather Geography Markup Language (dwGML) encoded NDFD data for a list of points at a single valid time.

    gmlListLatLon 38.99,-77.02 39.70,-104.80 List of WGS84 latitude and longitude pairs for the points for which you want NDFD data.   Each point's latitude and longitude value is seperated by a comma. Each pair (one latitude and longitude value) is separated by a space. Number of points requested can not exceed 200.
    requestedTime 2004-04-27T12:00:00 The time for which you want NDFD data.
    featureType Forecast_Gml2Point GML 2 Compliant Data Structure: Forecast_Gml2Point
    GML 3 Compliant Data Structures: Forecast_GmlsfPoint, Forecast_GmlObs, NdfdMultiPointCoverage
    KML 2 Compliant Data Structure: Ndfd_KmlPoint
    propertyName maxt,mint The NDFD parameters that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?gmlListLatLon=38.99,-77.02+39.70,C-104.80+47.6,-122.30&featureType=Forecast_Gml2Point&requestedTime=2009-04-22T23:59:59&propertyName=maxt,mint

    GML is an Open Geospatial Consortium standard for encoding geospatial data. You can learn about how the National Weather Service has used GML to develop application schema for encoding NDFD data by visiting the NDFD Web Feature Service home page.

    One of the advantages of NDFD GML is that it is a recognized standard. As a result, GML and application schema derived from it are supported by a number of GIS applications. There are examples of importing GML-encoded NDFD into several applications at the following link.

    Tutorials on integrating the NDFD WFS and clients like ArcGIS, Google Earth, Google Maps, and uDig..

    In addition to dwGML, the service can return Keyhole Markup Language (KML) encoded NDFD data by setting the featureType input to Ndfd_KmlPoint. KML can be viewed with freely available tools like Google Earth.

    Unsummarized Data for a Period of Time Encoded in dwGML: Returns Digital Weather Geography Markup Language (dwGML) encoded NDFD data for a list of points during a user specified time period.

    gmlListLatLon 38.99,-77.02 39.70,-104.80 List of WGS84 latitude and longitude pairs for the points for which you want NDFD data.   Each point's latitude and longitude value is seperated by a comma. Each pair (one latitude and longitude value) is separated by a space. Number of points requested can not exceed 200.
    startTime XML Date String 2008-01-01T00:00:00 The start time for which you want NDFD data.
    endTime XML Date String 2010-12-31T23:59:59 The end time for which you want NDFD data.
    compType string Between Comparison type. Can be IsEqual, Between, GreatThan, GreaterThanOrEqual, LessThan, or LessThanOrEqual.
    featureType string Forecast_Gml2Point GML 2 Compliant Data Structure: Forecast_Gml2Point
    GML 3 Compliant Data Structures: Forecast_GmlsfPoint, Forecast_GmlObs, NdfdMultiPointCoverage
    KML 2 Compliant Data Structure: Ndfd_KmlPoint
    propertyName comma delimited list maxt,mint,wx The NDFD element that you are requesting.   For valid inputs see the NDFD Element Names Page.

    A sample query string follows:

    http://www.weather.gov/mdl/survey/pgb_survey/dev/sample_products/browser_interface/ndfdXMLclient.php?gmlListLatLon=38.99,-77.02+39.70,-104.80+47.6,-122.30&featureType=Forecast_Gml2Point&startTime=2000-01-01T00:00:00&endTime=2010-01-01T00:00:00&compType=Between&propertyName=maxt,wx

    GML is an Open Geospatial Consortium standard for encoding geospatial data. You can learn about how the National Weather Service has used GML to develop application schema for encoding NDFD data by visiting the NDFD Web Feature Service home page.

    One of the advantages of NDFD GML is that it is a recognized standard. As a result, GML and application schema derived from it are supported by a number of GIS applications. There are examples of importing GML-encoded NDFD into several applications at the following link.

    Tutorials on integrating the NDFD WFS and clients like ArcGIS, Google Earth, Google Maps, and uDig..

    In addition to dwGML, the service can return Keyhole Markup Language (KML) encoded NDFD data by setting the featureType input to Ndfd_KmlPoint. KML can be viewed with freely available tools like Google Earth.

ndfdBrowserClientByDay.php Interface

    Single Point Summarized Data: Returns DWML-encoded NDFD data for a point. Data for each point is summarized for either a 24- or 12-hour time period

    lat 39.0000 The WGS84 latitude of the point for which you want NDFD data.   North latitude is positive.
    lon -77.0000 The WGS84 longitude of the point for which you want NDFD data.   West longitude is negative.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?lat=38.99&lon=-77.01&format=24+hourly&startDate=2009-04-21&numDays=7

    Multiple Point Summarized Data: Returns DWML-encoded NDFD data for a list of points. Data for each point is summarized for either a 24- or 12-hour time period

    listLatLon 38.99,-77.02 39.70,-104.80 List of WGS84 latitude and longitude pairs for the points for which you want NDFD data.   Each point's latitude and longitude value is seperated by a comma. Each pair (one latitude and longitude value) is separated by a space. Number of points requested can not exceed 200.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?listLatLon=38.99,-77.02+39.70,-104.80+47.6,-122.30&format=24+hourly&startDate=2009-04-21&numDays=7

    Summarized Data for a Subgrid: Returns DWML-encoded NDFD data for all the NDFD grid points within a rectangular subgrid as defined by points at the lower left and upper right corners of the rectangle.

    lat1 33.8835 The WGS84 latitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    lon1 -80.0679 The WGS84 longitude of the lower left point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    lat2 33.8835 The WGS84 latitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   North latitude is positive.
    lon2 -80.0679 The WGS84 longitude of the upper right point of the rectangular subgrid for which you want NDFD grid points.   West longitude is negative.
    resolutionSub 20.0 The default resolution for NDFD data is typically 5km. However, users can request latitude and longitude values for resolutions greater ( 10km, 15km, 20km, etc.) than the native resolution so as to reduce the number of points returned.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?lat1=35.00&lon1=-82.00&lat2=35.5&lon2=-81.50&resolutionSub=20.0&format=24+hourly&startDate=2009-04-21&numDays=7

    Summarized Data for a Line: Returns DWML-encoded NDFD data for all points on a line defined by the line's end points.

    endPoint1Lat 39.0000 The WGS84 latitude of the first end point of the line for which you want NDFD grid points.   North latitude is positive.
    endPoint1Lon -77.0000 The WGS84 longitude of the first end point of the line for which you want NDFD grid points.   West longitude is negative.
    endPoint2Lat 39.0000 The WGS84 latitude of the second end point of the line for which you want NDFD grid points.   North latitude is positive.
    endPoint2Lon -77.0000 The WGS84 longitude of the second end point of the line for which you want NDFD grid points.   West longitude is negative.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?endPoint1Lat=38.99&endPoint1Lon=-77.01&endPoint2Lat=39.99&endPoint2Lon=-78.01&format=24+hourly&startDate=2009-04-21&numDays=7

    Summarized Data for One or More Zipcodes: Returns DWML-encoded NDFD data for one or more zip codes (50 United States and Puerto Rico).

    zipCodeList 20910 The zip code of the area for which you want NDFD grid points.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?zipCodeList=20910+25414&format=24+hourly&startDate=2009-04-21&numDays=7

    Summarized Data for a Subgrid Defined by a Center Point: Returns DWML-encoded NDFD data for a rectangle defined by a center point and distances in the latitudinal and longitudinal directions.

    centerPointLat 39.0000 The WGS84 latitude of the center or the rectangle for which you want NDFD grid points.   North latitude is positive.
    centerPointLon -77.0000 The WGS84 longitude of the center or the rectangle for which you want NDFD grid points.   West longitude is negative.
    distanceLat 50.0 The distance from the center point in the latitudinal direction to the rectangle's East/West oriented sides.
    distanceLon 50.0 The distance from the center point in the longitudinal direction to the rectangle's North/South oriented side.
    resolutionSquare 20.0 The default resolution for NDFD data is typically 5km. However, users can request latitude and longitude values for resolutions greater ( 10km, 15km, 20km, etc.) than the native resolution so as to reduce the number of points returned.
    startDate 2004-04-27 The beginning day for which you want NDFD data.   If the string is empty, the start date is assumed to be the earliest available day in the database.
    numDays 7 The number of days worth of NDFD data you want.
    format 12 hourly There are two formats.   The “24 hourly” format returns NDFD data summarized for a 24 hour period running from 6:00 AM to 6:00 AM.   The “12 hourly” format summarizes NDFD data into two 12 hour periods per day that run from 6:00 AM to 6:00 PM and 6:00 PM to 6:00 AM

    A sample query string follows:

    http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?centerPointLat=38.0&centerPointLon=-97.4&distanceLat=50.0&distanceLon=50.0&resolutionSquare=20.0&format=24+hourly&startDate=2009-04-21&numDays=7

Once the REST Services returns the XML document back to the client, you can then parse the DWML using SAX, the DOM, or XSLT.

All latitude and longitude values provided as input or in the output DWML are based on the World Geodetic System 1984 (WGS84). For more inforation on the NDFD spatial reference system see the NDFD Spatial Reference System page.

Please note: There is an NDFD Web Services user forum that might be able to help developers with implementation language specific issues. The unofficial forum can be found at the following URL:

http://tech.groups.yahoo.com/group/NDFD_SOAP_Service/

What if I need lots of NDFD data or find the web service too slow?

You should consult the NDFD web services use guidelines.

The NWS has developed a program called degrib that can output NDFD data encoded in DWML. Degrib is a C program that allows you to visualize NDFD GRIB2 data and convert these binary files into other formats. If you are a web service user who wants DWML-encoded data for a large number of NDFD points, degrib will allow you to move the DWML-encoding process to your computer. By using degrib to process the NDFD data on a local computer, you may be able to significantly improve the speed with which your program is able to ingest NDFD data. The NWS makes a degrib executable available for Microsoft Windows PCs and the degrib source code available for compilation on other computer operating systems. To download degrib software, visit the URL http://www.nws.noaa.gov/mdl/degrib/register.php. Once you have the degrib software running, you will need to maintain updated NDFD GRIB2 files. For more information on downloading NDFD GRIB2 files from the NWS Telecommunication Operations Center, see the URL http://www.nws.noaa.gov/mdl/degrib/dataloc.php. For additional help on using degrib to convert NDFD GRIB2 files into DWML see the degrib tutorial and man page.

What if I prefer not to use a RESTful to access NDFD web services?

Please visit the following web pages:

    NDFD SOAP Service Home page

    NDFD WFS Home page

NWS XML Services Change Notices XML

Below are listed recent change notices for NWS XML services. A complete listing is available. An RSS feed of the change notices is also available. These notices are used to announce major changes, schema changes and new services.

 

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     Page last Modified: 6 October, 2005 10:31 AM