Is there any app that alert when barometric pressure drops on my Apple Watch?

Search the App Store for "barometer". I found a few apps, though I have no idea how well any would work since the barometric altimeter in the Watch is really intended for determining altitude, not atmospheric pressure per se. Nor do I know if any would provide an alert due to a drop in pressure. But you can look.

Regards.

For as far as i know the Apple Watch is not suitable to use as barometer