* Front month still well below recent 21-month high * Weather forecasts mixed throughout the nation * Nuclear power plant outages remain above normal * Coming Up: Baker Hughes gas drilling rig data Friday By Eileen Houlihan NEW YORK, May 17 (Reuters) - U.S. natural gas futures edged higher early on Friday, after a big, 3-percent drop on Thursday that followed the release of a third straight above-average weekly inventory build. But traders said milder, spring-like weather on tap for most of the nation in the coming days and weeks would do little to spur any early-season cooling demand. As of 9:26 a.m. EDT (1326 GMT), front-month June natural gas futures on the New York Mercantile Exchange were at $3.938 per million British thermal units, up 0.6 cent. The nearby contract hit a one-month low of $3.883 last week after climbing to a 21-month high of $4.444 on May 1. The latest National Weather Service six to 10-day forecast issued on Wednesday called for above-normal temperatures in the Southwest and along the mid-Atlantic Coast and below-normal readings along the Gulf Coast and in the Northwest. But normal temperatures were on tap for the majority of the country. Nuclear plant outages totaled 18,100 megawatts, or 18 percent of U.S. capacity, down from 19,800 MW out on Thursday, but up from 16,100 MW out a year ago and a five-year average outage rate of 17,700 MW. Thursday's gas storage report from the U.S. Energy Information Administration showed domestic inventories rose last week by 99 billion cubic feet, above Reuters poll estimates for a 95 bcf build, the year-ago gain of 56 bcf and the five-year average build for that week of 83 bcf. The build exceeded expectations for a third straight week, but total stocks, at 1.964 trillion cubic feet, are still more than 26 percent below last year's levels and more than 4 percent below the five-year average level. Early injection estimates for next week's EIA storage report range from 87 bcf to 100 bcf versus a 75-bcf build during the same week last year and a five-year average rise for that week of 90 bcf. Traders were waiting for the next Baker Hughes drilling rig report to be released on Friday, after last week's data showed the gas-directed rig count slid to an 18-year low of 350.