What that means is:
Live Forecast
If you are using a Davis Vantage Pro then you can display the forecast text provided
via Weather Display. To do so set this tag to a number between 1 and 99
corresponding to the number of seconds between the alternating of the current
conditions and the forecast text.
<showDavisForecast>10</showDavisForecast>
In this example the current conditions and forecast text will alternate at 10 second
intervals. Set to 0 to only show current conditions, set to 100 to only show forecast.
To make the icon follow the current conditions of forecast text set this tag to 1 –
<switchForecastIcon>1</switchForecastIcon>
Chuck