Update weather-forecast.markdown (#5674)

* Update weather-forecast.markdown

* Fixed external image link

source/_lovelace/weather-forecast.markdown

@@ -2,7 +2,7 @@
 layout: page
 title: "Weather Forecast Card"
 sidebar_label: Weather Forecast
-description: "TBD"
+description: "The Weather card allows you a visual card to display the weather."
 date: 2018-07-01 10:28 +00:00
 sidebar: true
 comments: false
@@ -10,4 +10,22 @@ sharing: true
 footer: true
 ---
 
-TBD
+Weather forecast is a card to display the weather. Very useful to include on interfaces that people display on the wall. 
+
+<p class='img'>
+<img src='/images/lovelace/lovelace_weather.png' alt='Screenshot of the weather card'>
+Screenshot of the weather card.
+</p>
+
+| Name | Type | Default | Description
+| ---- | ---- | ------- | -----------
+| type | string | **Required** | `weather-forecast`
+| entity | string | **Required** | Entity id of `weather` domain
+
+
+**Example**
+
+```yaml
+- type: weather-forecast
+  entity: weather.demo_weather_north
+```