"[T]he clear message from the other data is that the trend in overall growth has moved up from what has been a 2-to-2.5 percent average for most of the recovery," HFE's Jim O'Sullivan wrote in a research note. "[T]he combined ISM data look strong enough now to be consistent with a 5 percent trend."
Other analysts suggested the August number was probably an outlier.
"This is impossible to square with all the leading payroll indicators," Pantheon's Ian Shepherdson wrote in a client note. "So we are very much inclined not to take it seriously."
Read MoreActually, this jobs report holds water, says pro
Democrats should very much hope that the numbers tick back up in September because they remain in serious danger of losing the Senate.
A new poll out on Friday showed GOP Rep. Tom Cotton leading incumbent Democrat Mark Pryor 49 percent to 47 percent in the Arkansas Senate race. That is well within the poll's margin of error, making it a statistical dead heat. But anytime an incumbent is below 50 percent at this point they are in very serious trouble.
The latest numbers from Louisiana show another vulnerable Democratic incumbent, Sen. Mary Landrieu, below the 50 percent threshold and in danger of losing to GOP Rep. Bill Cassidy. GOP State Rep. Thom Tillis is also running neck and neck with Democratic incumbent Kay Hagan in North Carolina.
Read MoreNC debate reveals how party battles will be fought
Republicans need a net gain of six seats to gain control and are all but assured pickups in Montana, South Dakota and West Virginia. They need to win just three of the remaining seven toss-up races in Democratically held seats in Arkansas, Louisiana, Alaska, Colorado, Iowa, Michigan and North Carolina to get narrow control. And the party's discipline in nominating mainstream candidates unlikely to suffer the kind of Todd Akin-style meltdowns that characterized 2012 is clearly paying off.
Democrats have a chance at picking up an open seat in Georgia. And they retain at least some hope of knocking off Senate Minority Leader Mitch McConnell in Kentucky. But the more likely scenario is the GOP hanging on to all its current seats and adding at least six more.