* Front month remains below last week's 21-month chart high * Normal or below-normal temperatures back in forecasts * Nuclear power plant outages slip below average * Coming Up: EIA natgas storage data Thursday By Eileen Houlihan NEW YORK, April 24 (Reuters) - U.S. natural gas futures edged higher early on Wednesday, lifted by expectations that lingering cold weather in parts of the nation would continue to curb storage injections, further tightening the supply picture. "Natural gas may continue to get support from more cold weather," said Price Futures Group analyst Phil Flynn, noting gas continued to be the best performing commodity of the year. Lingering cold in consuming regions, spring power plant outages and a tightening supply picture helped lift nearby gas futures to their highest level in nearly 21 months last week. Futures are up about 36 percent since mid-February, after cold and lingering winter weather put a huge dent in inventories. As of 9:26 a.m. EDT (1326 GMT), front-month May natural gas futures on the New York Mercantile Exchange were at $4.269 per million British thermal units, up 3.1 cents, or under 1 percent. The contract rose to $4.429 last week, the highest level for a nearby contact since late July 2011. The latest National Weather Service six to 10-day forecast issued on Tuesday called for above-normal temperatures in a large portion of the Southwest and a small portion of New England, with normal or below-normal readings in Florida, Texas, the Northwest and across the mid-Continent. Nuclear outages totaled 23,600 megawatts, or 23 percent of U.S. capacity, down from 24,400 MW out on Tuesday, 25,100 MW out a year ago and a five-year average outage rate of 23,700 MW. INJECTION SEASON OFF TO SLOW START Last week's gas storage report from the U.S. Energy Information Administration showed domestic inventories rose in the prior week by 31 billion cubic feet, below Reuters poll estimates for a 34 bcf build and the five-year average gain of 39 bcf for that week. Stocks, at 1.704 trillion cubic feet, are nearly 32 percent below last year and more than 4 percent below the five-year average. Inventories started the heating season at record highs, but three weeks ago slid below the five-year norm for the first time since September 2011. Early injection estimates for Thursday's EIA report range from 19 bcf to 48 bcf, versus a 43-bcf build during the same week last year and a five-year average rise for that week of 50 bcf. Baker Hughes drilling rig data last week showed the gas-directed rig count rose two to 379, after hitting a 14-year low of 375 three weeks ago.