* FireEye jumps after Mandiant buy
* Light volume expected after snowstorm
* Automakers' December sales due
* Futures up: Dow 32 pts, S&P 3.9 pts, Nasdaq 6 pts
By Chuck Mikolajczak
NEW YORK, Jan 3 (Reuters) - U.S. stock index futures advanced modestly on Friday, after Wall Street began the new year with a decline and investors grappled with a snowstorm that blasted the northeastern United States.
U.S. stocks fell on their first day of trading in 2014 as investors booked profits in the wake of the S&P 500's best yearly advance since 1997, with many of last year's strongest performers down on the day.
After closing 2013 with a gain of 29.6 percent, its best yearly performance since 1997, the S&P 500 opened the year with a decline of 0.89 percent, as each of the ten major S&P sectors lost ground.
Market volume, already expected to be on the light side as many market participants remain out of the office due to the New Year's holiday-interrupted week, will likely be anemic after a snowstorm caused more than 1,000 U.S. flight delays and cancellations, paralyzed road travel, and closed schools and government offices.
"Slow just got slower. This session is not going to be anything to get excited about," said Keith Bliss, senior vice-president at Cuttone & Co in New York.
"Yesterday's session was interesting in that it was low volume and the selloff we had was nothing to get too panicked about."
S&P 500 futures rose 3.9 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures gained 32 points and Nasdaq 100 futures added 6 points.
Cybersecurity company FireEye Inc has acquired Mandiant Corp, the computer forensics specialist best known for unveiling a secretive Chinese military unit believed to be behind a series of hacking attacks on U.S. companies. FireEye shares jumped 20.8 percent to $49.67 in premarket trade.
Micron Technology Inc lost 1.8 percent to $21.27 before the opening bell after RBC lowered its rating on the stock to a "sector perform" from "outperform."
Investors will monitor automakers on Friday as they report their vehicle sales for December. Chrysler Group LLC reported a 6 percent gain last month in U.S. auto sales, its best December since 2007, but still narrowly missed analyst expectations. Ford Motor Co shares gained 1 percent to $15.59 in premarket.
European stocks edged higher, bolstered by a rally in retailers, but the major indexes remained below recent 5-1/2 year highs as investors locked in profits on a forecast-beating 2013.
Asian share markets were under water after a sudden reversal in some very popular, and thus crowded, trades sparked a bout of global risk aversion.