Add nws weather.

source/_components/nws.markdown

@@ -0,0 +1,70 @@
+---
+title: "NWS"
+description: "Instructions on how to integrate National Weather Service data within Home Assistant."
+ha_category: Weather
+ha_release: 0.99
+ha_iot_class: Cloud Polling
+---
+
+The `nws` platform uses the [National Weather Service](https://www.weather.gov) web API as a source for meteorological data for your location.
+
+## Configuration
+
+According to the [API documentation](https://www.weather.gov/documentation/services-web-api/), a string is required for the API key, and an email address is suggested to be included within the string.
+
+To add NWS to your installation using the closest station, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+weather:
+  - platform: nws
+    api_key: YOUR_API_KEY
+```
+
+To specify a station, for example, KADW (Andrews Air Force Base), use the following:
+
+```yaml
+# Example configuration.yaml entry
+weather:
+  - platform: nws
+    api_key: YOUR_API_KEY
+    station: KADW
+```
+
+A list of nearby stations is printed to the log with level `DEBUG` if no station is supplied. Stations can also be found on the [NOAA website](https://www.cnrfc.noaa.gov/metar.php). Codes with only three characters, for example, `ADW` should be prefixed with the letter K, `KADW`.
+
+The default forecast is day and night, `mode: daynight`, while `mode: hourly` gives the forecast hourly.  The forecast is obtained from the latitude and longitude value, not the station.
+
+{% configuration %}
+api_key:
+  description: "Your API key. Any string, but an email address is suggested to be included."
+  required: true
+  type: string
+latitude:
+  description: "Manually specify latitude. By default, the value will be taken from the Home Assistant configuration."
+  required: false
+  type: float
+  default: "Provided by Home Assistant configuration."
+longitude:
+  description: Manually specify longitude. By default, the value will be taken from the Home Assistant configuration.
+  required: false
+  type: float
+  default: "Provided by Home Assistant configuration."
+name:
+  description: "Name to use in the frontend."
+  required: false
+  type: string
+  default: "Station name."
+mode:
+  description: "The forecast type. Can be `daynight` or `hourly`."
+  required: false
+  type: string
+  default: daynight
+station:
+  description: "METAR station code."
+  required: false
+  type: string
+  default: "Closest station to `latitude` and `longitude` as returned by NWS API."
+{% endconfiguration %}
+
+Details about the API are available in the [NWS API documentation](https://www.weather.gov/documentation/services-web-api). The [pynws](https://github.com/MatthewFlamm/pynws) library is used to retrieve data.