The AUDUSD moved sharply lower following yesterday’s FOMC rate decision, but the selling momentum started to slow when the price reached an important technical support area.The decline extended to approximately 0.7078, where two key technical levels came together:The rising 100-day moving average at 0.70795The 50% retracement of the move up from the end-of-July low at 0.70773When different technical tools identify nearly the same price, that area tends to attract more attention from traders. Some traders may focus on the moving average, while others may be watching the retracement level. When both point toward the same area, it can create a stronger support or resistance target.In this case, the combination did a good job of slowing the decline. Sellers had their shot following the FOMC decision, but they could not sustain the momentum below the support cluster. Once the downside momentum faded, sellers started to cover their positions and buyers returned.That helped turn the price back to the upside.Fundamental forces are also helping the Australian dollarThe rebound is not being driven by the technical picture alone.US Treasury yields are moving lower today, reducing some of the support for the US dollar. At the same time, commodity prices—including gold and silver—are moving sharply higher.The Australian dollar is often sensitive to movements in commodities because Australia is a major commodity-producing and exporting country. Stronger commodity prices can improve the outlook for Australian export revenues and support demand for the Australian dollar.That relationship is not perfect from day to day, but when lower US yields, a softer US dollar and stronger commodities all move in the same direction, they can provide a supportive backdrop for the AUDUSD.The fundamental story gave buyers a reason to push higher. The technical support near 0.7077–0.7080 gave them a defined area from which to act.Why the 100-day moving average mattersThe 100-day moving average is watched by longer-term traders and investors as a measure of the broader trend.When the price is above a rising 100-day moving average, buyers generally have more control from a longer-term perspective. When the price falls below that moving average and stays below it, the bias begins to shift more in favor of sellers.The key is not simply whether the price trades briefly above or below the moving average. Markets can move through technical levels temporarily—especially following a major event such as an FOMC decision.What matters is whether the price can stay below the level and build momentum.Yesterday, sellers pushed AUDUSD into the 100-day moving average, but they could not extend the decline. The failure to sustain a break gave buyers the opportunity to take back control.Buyers improve the short-term pictureThe rebound gained momentum after AUDUSD moved back above 0.70908 and then 0.71017.Those breaks were important because they showed that the move higher was more than just a small bounce from support. Buyers were able to take back successive technical levels and force short-term sellers to reassess their positions.The 0.71017 level is now an important interim barometer for traders.Staying above that level keeps the short-term bias tilted more toward the buyers and allows the corrective move higher to continue. If the price moves back below 0.71017, the rebound would begin to lose some momentum.Below that level, 0.70908 would become the next downside target. A break below both levels would shift the market’s attention back toward the major support cluster between 0.70773 and 0.70795.The next resistance area will be the real testAlthough buyers have regained some short-term control, they still have more work to do.The next major resistance comes between approximately 0.71168 and 0.71270.That zone includes several technical levels:The 38.2% retracement at 0.71168A prior swing area extending toward 0.71270The falling 100-hour moving average near 0.71271The 100-hour moving average has been moving lower following the recent decline. That makes it a shorter-term trend-defining level and a natural target for buyers.A falling moving average often attracts sellers on the first test because traders who missed the original move lower may use the rebound as an opportunity to enter. Traders who bought near the lows may also take some profits as the price approaches resistance.That does not mean the price cannot move above the moving average. It means buyers will need to prove they can get above the level—and stay above it—before gaining greater technical control.What would make the picture more bullish?A sustained move above the 0.71168–0.71270 resistance area would be the next bullish signal.Such a break would take the price above the 38.2% retracement, above the prior swing area and above the falling 100-hour moving average. Clearing all three hurdles would give buyers more control and increase the potential for a deeper recovery.Until that happens, the rebound remains constructive but incomplete.The buyers successfully defended the longer-term support near the 100-day moving average. They have also reclaimed several shorter-term levels. The next step is proving that they can extend the move through the resistance clustered near 0.71168–0.71270.What would weaken the rebound?If AUDUSD cannot get through the resistance area and falls back below 0.71017, some of the bullish momentum would fade.A move below 0.70908 would add to the downside pressure and put the major support near 0.70773–0.70795 back in play.That area remains the most important downside barometer. As long as the price stays above it, buyers can argue that the broader move higher remains intact. A sustained break below the 100-day moving average and the 50% retracement would be a more bearish development and would return greater control to sellers.The trading lessonThe price action offers a good example of why traders should define technical levels before volatility increases.The FOMC decision provided the catalyst for the decline, but the technical levels identified where the selling momentum might slow. Traders did not have to guess where buyers could return. The 100-day moving average and the 50% retracement created a clearly defined support area.As I explain in my book Attacking Currency Trends, moving averages and retracement levels can help traders define the bias, control risk and identify the levels that would confirm—or invalidate—a trading idea.In this case, sellers had their shot at the longer-term support area but could not keep the price below it. Buyers responded and pushed the price back above short-term resistance.Now the burden shifts to the buyers. They need to keep the price above 0.71017 and ultimately break through the 0.71168–0.71270 resistance area to increase their control. This article was written by Greg Michalowski at investinglive.com.