Refresh the nexrad tiles every 5 mins.

public_html/layers.js

@@ -66,17 +66,26 @@ function createBaseLayers() {
                 }
         }
 
-        us.push(new ol.layer.Tile({
+        var nexrad = new ol.layer.Tile({
                 name: 'nexrad',
                 title: 'NEXRAD',
                 type: 'overlay',
-                source: new ol.source.XYZ({
-                        url : 'http://mesonet{1-3}.agron.iastate.edu/cache/tile.py/1.0.0/nexrad-n0q-900913/{z}/{x}/{y}.png',
-                        attributions: 'NEXRAD courtesy of <a href="http://mesonet.agron.iastate.edu/">IEM</a>'
-                }),
                 opacity: 0.5,
                 visible: false
-        }));
+        });
+        us.push(nexrad);
+
+        var refreshNexrad = function() {
+                // re-build the source to force a refresh of the nexrad tiles
+                var now = new Date().getTime();
+                nexrad.setSource(new ol.source.XYZ({
+                        url : 'http://mesonet{1-3}.agron.iastate.edu/cache/tile.py/1.0.0/nexrad-n0q-900913/{z}/{x}/{y}.png?_=' + now,
+                        attributions: 'NEXRAD courtesy of <a href="http://mesonet.agron.iastate.edu/">IEM</a>'
+                }));
+        };
+
+        refreshNexrad();
+        window.setInterval(refreshNexrad, 5 * 60000);
 
         if (world.length > 0) {
                 layers.push(new ol.layer.Group({