diff --git a/api/storm-forecast.js b/api/storm-forecast.js
index d7dbb19..97e4722 100644
--- a/api/storm-forecast.js
+++ b/api/storm-forecast.js
@@ -46,6 +46,17 @@ export default async function handler(req, res) {
         return res.status(405).json({ error: 'Method not allowed' });
     }
 
+    // TEMP DIAGNOSTIC — remove after debugging. Reports key presence (never the value).
+    if (req.query && req.query.debug === '1') {
+        const k = process.env.TOMORROW_API_KEY || '';
+        return res.status(200).json({
+            hasKey: k.length > 0,
+            keyLength: k.length,
+            expectedLength: 32,
+            node: process.version,
+        });
+    }
+
     const key = process.env.TOMORROW_API_KEY;
     if (!key) {
         console.warn('[storm-forecast] TOMORROW_API_KEY not set');