US STOCKS-Wall St turns lower as earnings concerns linger

* JPMorgan rises after results, Wells Fargo lower

* Norfolk Southern gives weak outlook, shares fall

* Nokia in talks to buy Alcatel-Lucent

* Dow up 0.2 pct, S&P flat, Nasdaq down 0.3 pct (Updates to midday trading)

By Ryan Vlastelica

NEW YORK, April 14 (Reuters) - U.S. stocks were flat on Tuesday as investors digested the initial major earnings of the first-quarter reporting season, which showed some weakness though companies topped lowered expectations.

Norfolk Southern Corp was the biggest decliner on the S&P 500, dropping 5.6 percent to $98.95 a day after it forecast a surprise drop in its first-quarter earnings and revenue.

Johnson & Johnson also cut its full-year forecast, citing the impact of a strong dollar, though adjusted earnings topped expectations. Shares of the Dow component were flat after earlier rising nearly 1 percent.

The weak outlooks offset a positive report from JPMorgan Chase & Co, which posted stronger-than-expected earnings growth, helped by a rebound in fixed-income trading. The stock rose 1.3 percent to $62.86.

"We are watching global companies to see how they were impacted by the dollar, and (J&J) suggests the impact could be worse than we thought," said Terry Morris, senior equity manager for National Penn Investors Trust Company in Reading, Pennsylvania. "A lot of companies are beating expectations, but that's due to cost-cutting, not increased demand. So far, this season is a yawn for the market."

Wells Fargo & Co dipped 0.8 percent to $54.15 despite. The company's first-quarter earnings fell from the prior year, though they were better than expected.

First-quarter profits for S&P 500 companies are seen falling 2.9 percent, according to Thomson Reuters data. On Jan. 1, analysts were looking for growth of 5.3 percent. The drop in expectations could mean that companies can more easily top a lowered bar, but the trend of the season remains unclear with fewer than 10 percent of the S&P having reported.

Nokia Oyj is in talks to buy Alcatel-Lucent SA , a deal that would combine the telecommunications industry's two weakest players but could pose challenges in cutting costs and overcoming political opposition.

U.S. shares of Nokia fell 4 percent to $7.97 while Alcatel rose 8.7 percent to $4.73.

U.S. retail sales posted their largest gain in a year since March, though the rise was slightly less than had been anticipated. Separately, U.S. producer prices rose in March after four straight months of declines.

The Dow Jones industrial average rose 28.63 points, or 0.16 percent, to 18,005.67, the S&P 500 gained 0.01 points, or 0 percent, to 2,092.44 and the Nasdaq Composite dropped 17.81 points, or 0.36 percent, to 4,970.44.

Advancing issues outnumbered declining ones on the NYSE by 1,723 to 1,160, for a 1.49-to-1 ratio on the upside; on the Nasdaq, 1,360 issues fell and 1,177 advanced for a 1.16-to-1 ratio favoring decliners.

The S&P 500 posted 2 new 52-week highs and no new lows; the Nasdaq Composite recorded 48 new highs and 20 new lows.

(Editing by Jeffrey Benkoe and Nick Zieminski)