Friday could be the day stocks take a run at breaking to new highs, but here's what could go wrong

Strong earnings momentum could drive the S&P 500 back to its all-time high in the very near future — if not Friday.

Earnings beats by big tech names could help boost the market, but the "Friday-afternoon effect" may short-circuit their run, as traders watch Washington and consider geopolitical concerns, like North Korea, ahead of the weekend.

Big oil reports earnings Friday, with both Exxon Mobil and Chevron expected before the bell. General Motors , Goodyear Tire, Synchrony Financial , Spirit Airlines and Colgate-Palmolive also report before the bell, as do Barclays, UBS, Sanofi, Sony, and Honda.

But traders are watching to see if Thursday's after-hours movers carry the morning. Alphabet and Amazon.com both surged nearly 4 percent, driving Nasdaq futures higher late Thursday. But after-the-bell earnings disappointments from Microsoft and Intel weighed on their stocks and tugged on Dow futures.

"Amazon and Alphabet stole the show. It's just a question of which psychology is going to have more effect on the market," said Scott Redler, partner with T3Live.com, who follows short-term technicals. Starbucks also reported profits but missed on its revenues. Its stock was down nearly 5 percent late Thursday.

Wunderlich Securities chief market strategist Art Hogan said earnings should certainly help drive the S&P back to 2,400 soon. "It feels like the earnings season on balance is remarkably good; not just good, but remarkably good. You have 80 percent of the companies in the S&P beating estimates," he said.

He said the market may not be able to hold its gains into the afternoon, even if it opens higher. "Fridays are tough. It's the Friday effect. What do you do Friday afternoon, ahead of a weekend where you don't know what's going on around the globe?" he said.

There is also first quarter GDP Friday, expected to show sluggish growth below 1 percent when it is released at 8:30 a.m. ET. "It's much about the rear-view mirror. The hard data you want to focus on is the earnings, not the GDP report," Hogan said.

Congress could approve a stop-gap measure Friday to allow it to work on a continuing resolution into next week. If not, the government would run out of funding and shut down, but traders do not expect to see that scenario.

The S&P 500 closed up 1 point at 2,388 Thursday, and the Nasdaq was up 23 at 6,048, a new high. The Dow rose 6 to 20,981. Treasury yields, which move inversely to prices, slipped. The 10-year was at 2.29 percent in late trading, and bond traders said the market was eyeing economists' cuts to first-quarter GDP forecasts, ahead of the report, as well as the action in Washington over the budget extension.

The oil market was also a concern. West Texas Intermediate crude futures fell more than 1 percent, to $48.97, before dipping lower on supply concerns.

Hogan said oil's recent drop won't be reflected in the reports of Exxon and Chevron but the oil majors could comment on the outlook.

"I'd love to see oil catch a bid here. It broke technically. It's really dragging the energy sector down. I don't know what the catalyst is going to be to get that to firm up," said Hogan.

Besides GDP, other data includes the employment cost index at 8:30 a.m. ET, Chicago PMI at 9:45 a.m. and consumer sentiment at 10 a.m.