The phrase "are not immediately evident" is correct and usable in written English.
It can be used when discussing something that is not clear or obvious at first glance.
Example: "The reasons for the project's failure are not immediately evident, requiring further investigation."
Alternatives: "are not readily apparent" or "are not clearly visible".
The reasons that Lumumba provoked such intense emotion are not immediately evident.
Instead of giving a crude tutorial, I will use this post to highlight some potential uses for this tool that are not immediately evident.
While all contain the same data, the figures suggest an interpretation and highlight trends that are not immediately evident in the table.
While they are readily identified by the pathologist as invading malignant cells, their relationship with the compact-appearing portions of the tumour as well as the mechanism underlying the development of this pattern are not immediately evident at histological level.
Related to this alter type of demonstration is the process of induction (inductio), which is helpful for discovering principles that are known naturally but are not immediately evident.
This conflict has, perhaps in ways that are not immediately evident, changed the strategic environment for both Israel and the Palestinians.
Her pupils' difficulties aren't immediately evident to the visitor in class.
While the origins of the project aren't immediately evident, the effect is. "How would we look without our heads, without our body engine?" Pepe asks, explaining the project.
Józef Bocheński related (personal communication) that once when he went to visit Łukasiewicz in Warsaw before the war, Łukasiewicz conveyed him inside excitedly, indicated a complex formula, beginning something like '$CCC\ldots$', and said, "Look at this beautiful and self-evidently true formula!" Clearly the formula's truth was not immediately evident to the bemused Bocheński.
But the effects of that order were not immediately evident.
