diff --git a/lighthouse-logger/index.js b/lighthouse-logger/index.js
index 176aeb20cb74..fa9f667459de 100644
--- a/lighthouse-logger/index.js
+++ b/lighthouse-logger/index.js
@@ -89,6 +89,9 @@ class Log {
       case 'verbose':
         debug.enable('LH:*');
         break;
+      case 'warn':
+        debug.enable('-LH:*, LH:*:warn, LH:*:error');
+        break;
       case 'error':
         debug.enable('-LH:*, LH:*:error');
         break;
diff --git a/types/externs.d.ts b/types/externs.d.ts
index a634d8e3df70..bc458f3823d2 100644
--- a/types/externs.d.ts
+++ b/types/externs.d.ts
@@ -18,7 +18,7 @@ export interface Flags extends SharedFlagsSettings {
   /** The hostname to use for the debugging protocol, if manually connecting. */
   hostname?: string;
   /** The level of logging to enable. */
-  logLevel?: 'silent'|'error'|'info'|'verbose';
+  logLevel?: 'silent'|'error'|'warn'|'info'|'verbose';
   /** The path to the config JSON. */
   configPath?: string;
   /** Run the specified plugins. */