The weather isn't the only thing dogging the U.S. economy lately, BlackRock's chief investment strategist told CNBC on Friday.
The other major culprit? A need for disposable income growth, according to BlackRock's Russ Koesterich.
"The reality is that in the long term, the economy needs to generate top-line growth, and for the economy to grow faster the consumer needs to spend faster," Koesterich said on "Squawk on the Street." "If income is constrained, it's going to be hard to see that expected pickup in consumption. So to me that's the linchpin of this."
(Read more: US cold snap's latest victim: Industrial output)
A batch of fresh weaker-than-expected economic data released Friday left U.S. stocks mixed, a day after disappointing retail numbers.