* Milder weather for the next week expected to slow gas use * Nuclear plant outages slip back below normal * Coming up: Reuters natural gas storage poll Wednesday By Joe Silha NEW YORK, April 9 (Reuters) - U.S. natural gas futures ended lower on Tuesday for a second day, as investors took profits amid mild weather forecasts for the eastern half of the nation, but concerns about below-average inventory levels limited the downside. Gas prices have been on a tear since mid-February, spiking nearly 30 percent as cold weather and above-average nuclear plant outages boosted demand for the fuel and helped whittle down inventories, which had hit a record high in November. Last week, storage dropped below the five-year average for the first time since September 2011, a supportive sign particularly with another draw expected this week. But some traders said the market, which rose in seven previous weeks, may be ripe for a pullback, with milder weather likely to slow demand and prices now at levels that make gas less competitive against coal for power generation. "Some selling may be profit taking; the market had a good run and people may be getting out to see how the shoulder (spring) season unfolds, but there's also some bearish sentiment starting to build," said Aaron Calder at Gelber & Associates. Front-month gas futures on the New York Mercantile Exchange ended down 6.5 cents, or 1.6 percent, at $4.017 per million British thermal units after trading between $4.004 and $4.104. The front contract slid 2.6 percent in the last two sessions. On Monday, it hit a 20-month high of $4.18 before closing lower, raising concerns about a possible technical reversal to the downside. Chart traders agreed that record growth in open interest over the last seven weeks, up more than 25 percent as prices mostly moved higher, indicates that speculative traders have added a lot of new length, which could leave the market vulnerable to a sharp sell-off when longs opt to take profits. Forecaster Commodity Weather Group noted that the six-to-10-day outlook turned warmer overnight for the East Coast and parts of the Midwest, with temperature highs in lower Mid-Atlantic states possibly breaking above 80 degrees Fahrenheit again. ONE MORE STORAGE DRAW EXPECTED Inventory draws have exceeded market expectations in six of the last seven weeks. Withdrawal estimates for Thursday's EIA report range from 1 to 46 bcf, with most in the low- to mid-20s. Stocks rose 11 bcf during the same week last year, while the five-year average increase for that week is 15 bcf. That should be the season's last decline, with early estimates for next week's report all looking for a modest build. U.S. Energy Information Administration data Thursday showed total domestic gas inventories fell last week to 1.687 trillion cubic feet, 32 percent below last year's record highs at that time and 2 percent below the five-year average. Stocks peaked last year in November at a record high 3.929 tcf but will end the heating season about 820 bcf below last winter's record high finish of 2.48 tcf and 4 percent below average for that time. WHEN WILL OUTPUT SLOW? Baker Hughes data on Friday showed the gas-directed drilling rig count fell last week for the fifth time in six weeks, dropping by 14 to a 14-year low of 375. Recent rig declines have raised expectations that output might finally be poised to slow from 2012's record high. In its short-term energy outlook on Tuesday, EIA trimmed its estimate for domestic gas production growth in 2013 but still expects output to rise 0.3 percent from 2012's record levels. The agency expects consumption this year to gain 1 percent.