Is foreknowledge logically impossible?

I would think anyone arguing the possibility of foreknowledge would hold the view that the past, present, and future all exist simultaneously and we are just living in the present. A being that doesn't exist within our local presentation of time could, theoretically, have access to our future. Or, I don't see a logical problem with the claim that a being that doesn't exist within our local presentation of time communicating information to us about our future (let me be clear that I don't believe this is happening, but I don't see a logical problem with the idea that it could happen).

For some future event to be known, i.e., known in the sense I understand you are using it here, then the future must be predetermined. For this reason, I have found this subject is most often discussed in a “free will” context. 

You ask: “why true foreknowledge is logically impossible?”  I would restate the question more like: Is foreknowledge logically possible? The short answer is: You cannot foretell the future. If you could, then the future is predetermined. If the future is predetermined, then no knowledge is possible.

Bo’s motto is “Expose an irrational belief, keep a person rational for a day. Expose irrational thinking, keep a person rational for a lifetime.” Much of his work is in education—not teaching people WHAT to think, but HOW to think. [From his web page.]

How can one teach anything to another if everything is predetermined? Actually, the situation is worse. No knowledge, none, is possible, and one cannot tell fallacy from the truth.

Let me explain what I mean. Assume for the moment that which a man does, he had to do. That which he believes, he had to believe. If he focuses his mind, he had to. If he evades the effort of focusing, he had to. He couldn’t help it. No one can help anything. Such is the determinist thesis, no matter what variant of determinism we examine.

Under this scenario, no fact or theory could claim greater plausibility than any other—including the theory of determinism—and knowledge is impossible. 

In general, I like to ask two critical questions: (1) what do you know? and (2) how do you know it?

A short definition of knowledge is the correct identification of the facts of reality. To know that the contents of your mind constitute knowledge, to know you correctly identified the facts of reality, we require a means of testing our conclusions. The means is the process of reasoning, logic, continually testing our conclusions against reality, and searching for contradictions. It is thus that we validate our findings.

This is part of Bo’s motto: “Expose irrational thinking, keep a person rational for a lifetime.” The correct identification of the facts of reality is an ongoing lifetime process. 

This validation is possible only if the capacity to judge is free. (Again, let me forestall some immediate criticism and say I am discussing people with a normal brain function.) But if the capacity to judge is not free, there is no way to discriminate between the correct identification of the facts of reality (beliefs) and hallucinations or dreams. 

The fallacy, among others, is the Fallacy of the Stolen Concept. 

I'd say your whole premise is goofy. Logicians don't deal in magical thinking, they deal in probabilities, and Bayesian calculations at best, but not "foreknowledge" or prophecy, oracles, or predictions.

This is just a form of mental masturbation or what scientists describe as the lunatic's formula that claiming anything above a 60 to 80% chance is risky. 

Since the future event has not yet taken place, the outcome is as yet uncreated, and neither has its value,

The word “value” is not defined enough. I guess that you mean a truth-value and that you are hence saying that the future event (the outcome) does not, unlike a present events, have a truth-value. My response would then be that your argument is working with a category mistake. Events, past, present or future could not have truth-values anyways—being true or false is a property of  statements . That was only my guess as what you mean, so can you clarify what a value is?