* Front month still below recent 21-month high * Above-normal temperatures on tap for Northeast * Nuclear power plant outages remain below normal * Coming Up: Baker Hughes gas drilling rig data Friday By Eileen Houlihan NEW YORK, May 31 (Reuters) - U.S. natural gas futures prices seesawed on either side of unchanged territory early Friday, with near-term heat blanketing consuming regions in the Northeast expected to limit more losses. Traders said the first real stretch of above-normal temperatures in the Northeast this spring has spurred early season cooling demand and served as a reminder that summer weather would arrive soon. As of 9:22 a.m. EDT (1322 GMT), front-month July natural gas futures on the New York Mercantile Exchange were at $4.019 per million British thermal units, down 0.4 cent, after trading between $4.009 and $4.064. The nearby contract fell nearly 6 percent in the past four consecutive sessions. It hit a one-month low of $3.883 on May 9 after climbing to a 21-month high of $4.444 on May 1. Data from the U.S. Energy Information Administration on Thursday showed inventories rose last week by 88 billion cubic feet, in line with Reuters poll estimates, but above the year-ago build of 72 bcf. Stocks have gained 92 bcf on average that week over the past five years. Stocks, at 2.141 trillion cubic feet, are 664 bcf, or nearly 24 percent, below year-ago levels. They are also 88 bcf, or nearly 4 percent, below the five-year average. Early estimates for next week's EIA gas storage report range from 78 bcf to 95 bcf versus a year-ago gain of 63 bcf and a five-year average build of 92 bcf for that week. Forecaster MDA Weather Services called for a hot weekend in the Northeast and showed above-normal temperatures in the entire region in its one- to five-day forecast map. The latest National Weather Service six- to 10-day forecast issued on Thursday called for above-normal temperatures in the western third of the nation and in the Northeast, and mainly normal readings elsewhere. Nuclear plant outages totaled 12,400 megawatts, or 12 percent of U.S. capacity, down from 13,600 MW out on Thursday, 17,700 MW out a year ago and a five-year average outage rate of 13,700 MW. Traders awaited the next Baker Hughes gas drilling rig report to be issued later Friday. Last week's report showed the gas-directed rig count was unchanged at 354. The count posted an 18-year low of 350 three weeks ago.