SPY 135-minute charts show the beginning of a downslope with the 5-bar ema below the 20-bar ema. On shorter time-frame a bear flag has been forming (Wave B), but the tendency is for the trend be established with this 5/20 bar cross on the 135-minute chart. Any intra-day spikes above the 20-bar ema would be shorting opportunities. Be careful with shorts if the 5-bar rises above the 20-bar ema. As Eric has said, Monday may see a spike as part of the end of a Wave B, but the Wave C should follow shortly. MACD is bearish with negative divergence which, while not as reliable, corroborates a weak chart.
Likewise, the IWM (135-minute) has the 5-bar below the 20-bar ema. This chart looks weaker, having already made a lower high. Transports have not confirmed the recent high in large caps. T.Lo has pointed out that in the last gasps of a bull-run, the safe large caps tend to get the last buyers, so this could be a sign of weakness in the market.
Other charts to consider would be the dollar and Vix, whcih are both forming bottoming patterns.