Custom Widget Variables / Dictionary Variables

Custom Widget Variables / Dictionary Variables

Hello,
I have created a custom widget that pulls weather data.  This is being used on a Blueprint Dashboard.  I am trying to display local weather information based on the Lat/Long from the GPS tracking device.  How can the Custom Widget access variables from my bucket?  

In my example below, I have hard coded the lat/long.  How can I use the latitude variable in my devices bucket?