perceptibly

This term describes a change or quality that is just strong enough to be detected by the senses or the mind. It often implies a subtle shift that, while not necessarily dramatic, is clear enough to be measured or acknowledged. It is frequently used in technical, scientific, or formal contexts to describe gradual transitions.

Compared to "noticeably," which is more common in everyday speech, "perceptibly" carries a slightly more clinical or precise tone. It suggests a threshold of perception has been crossed, making it an ideal choice for describing physical phenomena like temperature shifts, speed changes, or slight alterations in mood.