add pressure/windspeed chart with status shading

app/server.R

@@ -521,6 +521,40 @@ server <- function(input, output, session) {
     )
   })
 
+  output$track_met_chart <- renderDygraph({
+    track_data <- storm_track()
+
+    ts_data <- track_data %>%
+      select(datetime, windspeed, pressure) %>%
+      rename(Windspeed = windspeed, Pressure = pressure)
+
+    track_xts <- xts(
+      ts_data %>% select(-datetime),
+      order.by = ts_data$datetime
+    )
+
+    g <- dygraph(track_xts) %>%
+      dyAxis("y",  label = "Windspeed (kt)") %>%
+      dyAxis("y2", label = "Pressure (mb)", independentTicks = TRUE) %>%
+      dySeries("Windspeed", axis = "y",  color = "#4dabf7") %>%
+      dySeries("Pressure",  axis = "y2", color = "#f03e3e") %>%
+      dyOptions(drawGrid = FALSE) %>%
+      dyLegend(show = "always")
+
+    Reduce(function(g, i) {
+      g %>% dyShading(
+        from  = track_data$datetime[i],
+        to    = track_data$datetime[i + 1],
+        color = paste0(track_data$line_color[i], "33")
+      )
+    }, seq_len(nrow(track_data) - 1), init = g)
+  }) %>%
+    bindCache(
+      storm_selection$storm_year,
+      storm_selection$storm_name,
+      storm_selection$storm_basin
+    )
+
   storm_yearly_normalization <- reactive({
     req(
       storm_selection$storm_basin,