The part of speech "in the upcoming days" is correct and usable in written English. It could be used when discussing upcoming events or challenges. For example, "We will be facing many difficult challenges in the upcoming days.".
"In the upcoming days, the Egyptian team in charge of this case will head to Rome to discuss ways to enhance mutual coordination in this regard".
The N.H.L. and the players union resumed collective bargaining talks in Toronto and expect to be in contact again in the upcoming days.
At this point, it remains unclear whether these snap assessments and others made immediately after the debate will be matched by the more sober judgments of voters in the upcoming days.
In the upcoming days, it's almost inevitable that there will be a player, coach or executive who will slip and say something ugly or ignorant, and they will mostly likely have to respond to the well-deserved backlash that will follow.
Nowcasting for the upcoming few hours and forecasting for the upcoming days is treated separately.
Her latest cowriting effort is the upcoming "Days Out of Days".
The upcoming days are filled with exciting shopping opportunities.
Being a terminologist, I care about word choice. Ludwig simply helps me pick the best words for any translation. Five stars!
Maria Pia Montoro
Terminologist and Q/A Analyst @ Translation Centre for the Bodies of the European Union