The phrase "are most palpable when" is correct and usable in written English.
It can be used to indicate that something is most noticeable or evident during a specific time or under certain conditions.
Example: "The emotions in the room are most palpable when the final decision is announced."
Alternatives: "are most evident when" or "are most pronounced when".
Mr. Obama's struggles with Syria are most palpable when he tries to sum up his foreign-policy legacy.
Like Don Draper on a drug-fueled weekend in Vegas or Tony Soprano on an average afternoon at the Bada Bing, Baratheon has a gruffness that only thinly conceals his despair, and his dissatisfaction and longing are most palpable when he's gamely mimicking the indulgences of his glory days.
When it came time to shoot one of the film's most harrowing scenes, the feeling on set was palpable.
Her fierceness is most palpable when she blows up a balloon and puts it against her throat to demonstrate that she has figured out how to sing.
In fact, the class divide in the black community is now seen by some as a permanent aspect of our existence.' The sense that the ghetto is now a place of no escape is most palpable when Gates wanders around the Ida B Wells housing project in Chicago, visibly shocked by its desolation.
Publicly, I think, unease was most palpable when an armada of Google's camera-equipped Subaru cars, touring the world and taking photos to prettify its map service, turned out to be absorbing data from people's personal Wi-Fi accounts en route.
A sense of dislocation is perhaps most palpable when Busch discusses his acting career, which has produced some "surreal" moments in which he ends up performing the very roles he has actually — or might have — undertaken.
Marshall raised her gloves but her despondency was palpable when the referee raised the hand of her most persistent tormentor.
Still, there is a palpable unease when talking about immigration.
There's palpable disappointment when they finish.
