The shorts might have been looking for the market to retest last Wednesday low. When the market broke above the short term declining trend line, the shorts appeared to have decided to cover their positions and pushed the indexes to their high of the day near the close.
The SP500 once again came within the 2079.11 support level and bounced. The SP500 closed at 2102.44, a gain of 10.90 or 0.52%. The near term potential resistance is 2108.86 and the potential support remains to be 2079.11.
SPX
(click on the chart to enlarge)

The SPY closed at 210.59 with a gain of 1.17 or 0.56%. The potential support remains to be 207.95 and the potential resistance is 211.63/211.99.
SPY

The Nasdaq 100 moved above the 5/27/15 close and close above the 4/27/15 intraday high at 4566.37 with a gain of 35.63 or 0.79%. The near term potential support is revised to 4506.19, while the potential resistance remains to be the 7/22/15 price gap near 4643.83.
NDX

Last week, the RUT was the weakest performer and it was lagging the other indexes. Today, it was the best performer amongst the major indexes. It closed at 1225.09, well above the 1251.42 resistance level with a gain of 12.40 or 1.02%. By closing above the 1215.42 level, the 1238.76 level is in play as the potential resistance, and the revised potential support level is 1215.42.
RUT

It was mentioned in last weekly market recap that the market might have reached a turning point and a transition could be taking place to reverse the near term direction from down to up. Today price action could be the beginning of that transition.