Added NCI Explorer tech alert entry

docs/tech-alerts-changelog/_tech_alerts_changelog.md

@@ -19,6 +19,10 @@
 
 Learn more about the [DEA Summary Product Grid](/guides/reference/collection_3_summary_grid/).
 
+## 2024-08-08: NCI Explorer may be unstable
+
+The NCI Explorer has experienced some intermittent outages recently. We are currently investigating the cause of the issue. If the NCI Explorer fails to load, please try again later.
+
 ## 2024-08-02: Version 4.0.0 of DEA Geometric Median and Median Absolute Deviation released
 
 The newly released version 4.0.0 of [DEA Geometric Median and Median Absolute Deviation](/data/product/dea-geometric-median-and-median-absolute-deviation-landsat/) contains new features and changes such as the following.