Stocks galloped ahead Thursday as the market’s condition switched to a confirmed uptrend. The Nasdaq staked a 1.4% gain, its best price pop since Jan. 22. The S&P 500 and the Dow Jones industrial average chipped in gains of 1.1% each. The IBD 50 rose 1.4%. Volume fell on the NYSE but rose about 4% on the Nasdaq. A follow-through day, which signals a new uptrend underway, involves a sizable price gain in a major index.