* Charts turn bearish after Monday's close below support * High storage, production also weigh on prices By Joe Silha NEW YORK, Jan 29 (Reuters) - U.S. natural gas futures ended lower on Tuesday, with milder Northeast and Midwest weather forecasts this week driving the front-month February contract lower at expiration. The front contract, which hit a 6-1/2-week high of $3.645 early last week, lost 9.5 percent in the last six sessions as U.S. temperatures moderated. That marks the biggest six-day slide for front futures in nearly seven weeks. Traders have mostly shrugged off the brief cold shot expected later this week and early next week, focusing instead on concerns that the back half of winter may not turn out cold enough to whittle down excess supplies. "The forecasts are turning pretty warm, which is going to mean more gas left in inventory at the end of winter. If the outlook doesn't change (turn colder) soon, prices could break below $3 again," a Texas-based producer said. Front-month February gas futures on the New York Mercantile Exchange expired down 6.3 cents, or 1.9 percent, at $3.226 per million British thermal units after trading in a fairly narrow range between $3.207 and $3.275. Technical traders on Monday noted front futures gapped lower and closed below the 100-day moving average in the $3.40 area, a possible bearish sign that could set the stage for a test of next support at the 2013 low of $3.05 hit earlier this month. The 200-day moving average lies just below that at $3.01. In its Tuesday report, MDA Weather Services noted that both the six-to-10-day and 11-to-15-day forecasts continued to trend warmer, with computer models in good agreement about the outlook. Many traders remain skeptical of any upside in prices until much colder weather arrives, with inventories still relatively high and production flowing at or near a record pace. BIG STORAGE DRAW FAILS TO FIRM PRICES While weekly inventory withdrawals have topped market expectations for four straight weeks, traders noted that stocks are still high at 320 billion cubic feet (bcf), or 12 percent, above the five-year average. Early withdrawal estimates for Thursday's inventory report range from 197 to 221 bcf. That would be well above the 149 bcf drawn from inventory during the same week last year and the five-year average decline of 178 bcf for that week. If drawdowns for the rest of winter match the five-year average, inventories will end March at 2.048 tcf, about 18 percent above normal but 17 percent below last year, when stocks finished a very mild heating season at a record-high 2.48 tcf. GAS RIG COUNT GAINS, FIRST TIME IN 3 WEEKS The Baker Hughes gas-directed drilling rig count gained last week for the first time in three weeks. The overall count at 434 is not far above the 13-1/2-year low of 413 posted in early November, but so far production has shown no significant sign of slowing. The Energy Information Administration estimates that gas output in 2013 will hit a record high for the third straight year.