The phrase "a considerable challenge but" is correct and usable in written English.
It can be used to introduce a contrast or an exception to a statement about a challenge that is significant in nature.
Example: "The project presents a considerable challenge but offers great rewards for those who persevere."
Alternatives: "a significant obstacle yet" or "a major difficulty however".
Designing code that simultaneously meets multiple design constraints is a considerable challenge, but luckily there are techniques and tools that we can use to help us through the design process.
"A December deadline is a considerable challenge, but right now Angola needs to set and rise to such challenges".
The integration of data from different 'omic' techniques presents a considerable challenge, but by combining datasets as part of a data fusion process, it is possible to produce information of greater value than that obtained from the individual datasets.
This is a considerable challenge, but comparative genome analysis has already revealed fungal-specific genes and signaling pathways that are important in pathogenesis in diverse species, while targeting further intervention into fungal cell wall biogenesis also offers considerable promise.
The relatively poor experimental tractability of many of the organisms within the additional eukaryotic super-groups poses a considerable challenge, but the availability of genome sequences from some of these taxa can facilitate rapid identification of factors in such systems.
But a considerable challenge remains.
It is large enough to represent a considerable challenge to the casual reader but I hope those who find time to study it will find that it has contributed to their understanding.
The company will have a considerable challenge entering the North American market, but might have better success tackling other less well-covered markets, thanks to its availability in French, German, Spanish, Dutch and Portuguese in addition to English and Italian.
Analysts tend to view both men as talented but up against a considerable challenge that they have not yet conquered.
It's not up there with Dark Souls or Bloodborne in terms of difficulty, but it'll provide a considerable challenge.
A considerable challenge is the inherent difference between partner organizations but also between Member States.
