The phrase "almost unexpected" is correct and usable in written English.
It can be used to describe a situation or event that was not anticipated, but to a certain degree, it was somewhat foreseeable.
Example: "The sudden rainstorm was almost unexpected, as the weather forecast had only predicted a slight chance of showers."
Alternatives: "nearly surprising" or "partially unforeseen".
The drive of the Marines into the capital seemed almost unexpected today.
Her choice four years later was a real testament about how our relationship has lasted and how she has matured into the role — a certain consistency that was almost unexpected.
These have been a long time coming, but change is now rushing in with an almost unexpected swiftness and in the rush to replicate the professionalism of the men's game there's an inclination to ape it in every regard.
But she has not been seen on Broadway much in recent years — a role in the 2002 revival of "Morning's at Seven" was her most recent appearance — so her return in this lengthy part in an emotionally draining play is both exciting and almost unexpected.
What's there is almost unexpected.
An almost unexpected by-product of the parallel investigation of vertebrate and invertebrate nervous systems that is explored in this article is the emergent view of an intricate web of evolutionary homology and convergence exhibited in the structure and function of the nervous systems of these two large, paraphyletic groups of animals".
Bear in mind that surrogates are primarily storytellers, and the best stories are those with surprising elements — they're almost always about unexpected, unscripted incidents.
Whether explicit or subtle, his segues were almost always unexpected and revealing.
This has been a mini-stimulus for the economy, and one that was almost completely unexpected.
It was panic, almost totally unexpected and, in the view of many market professionals, almost totally uncalled for.
Guests turned around and saw something almost as unexpected as a groomsman with a bullwhip and fedora: a man in a dinner jacket acting as the flower girl.
