WINDERMERE, Fla. ( Stockpickr) -- Professional traders running mutual funds and hedge funds don't just look at a stock's price moves; they also track big changes in volume activity. Often when above-average volume moves into an equity, it precedes a large spike in volatility.Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors." >>5 Stocks Set to Soar on Bullish Earnings Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it's always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock. With that in mind, let's take a look at several stocks rising on unusual volume today. >>5 Rocket Stocks to Buy for a 1Q Rally Harris Teeter Supermarkets Regional supermarket chain operator Harris Teeter Supermarkets ( HTSI) is trading up 6.2% at $39.24 in recent trading. Today's Volume: 481,000 Average Volume: 197,785 Volume % Change: 352% From a technical perspective, HTSI is soaring here right off its 50-day moving average of $37.60 and back above its 200-day moving average of $38.69 with above-average volume. This move is quickly pushing shares of HTSI within range of triggering a near-term breakout trade. That trade will hit if HTSI takes out some near-term overhead resistance at $39.91 with high volume. Traders should now look for long-biased trades in HTSI as long as it's trending above its 200-day at $38.69, and then once it sustains a move or close above $39.91 with volume that hits near or above 197,785 shares. If that breakout triggers soon, then HTSI will set up to re-test or possibly take out its next major overhead resistance levels at $41.46 to $41.57. Any high-volume move above those levels will then put $43 into range for shares of HTSI. National Fuel Gas Company Diversified energy company National Fuel Gas Company ( NFG) is trading up 5% at $53.79 in recent trading.