Unfortunately, triangles are one of the hardest to forecast and track. It's not until at least three legs have completed that it starts to move up the list from "possible" to "probable" and when the fourth leg completes it is then much more "likely". Note that triangles can even have nine legs... Because for all we know, price could have done a simple a,b,c corrective move in the form of a or flat. So we need to track all these options at first and eliminate them one by one as more market data becomes available. So, after you have read this it should become clear there are NO certainties in the markets. If you want certainty, please put your money in a savings account. If you can come to grips with this uncertainty, and realize that is thus a great forecasting tool that can track multiple options at the same time, and where if/then scenarios based on price breaking above or below a certain price level help eliminate options and that those price levels can help you in your trading for profit taking and/or stop(losses), then you're really starting to master your understanding of how markets work.
With that in mind, let's look at the options currently available. The first is that the S&P500 has completed classic symmetrical triangle. It is a continuation pattern, meaning that the move going into the triangle will continue. In this case it was the move from 3029 DOWN to 2822 that was the initiation move. Assuming SPX2939 was the top of the b-wave, then simple symmetry targets: 2939 - (3029-2822) = 2732. Applying triangle "rules", then depending on where exactly price will move below the lower of the triangle -say at 2829- then we're looking for 2622. So we have a SPX2732-2622 target zone, which we can refine once more price data becomes available.
The other options the market still has at this moment is to complete a diagonal pattern (labeled as "alt: 3", alt: 4"). A simple 5=1 then targets SPX2957. This would best count as what is called an in terms as the sub-waves count best as 3s and not 5s. A break and close below SPX2890 will take IMHO this option off the table. Note how price so far pretty much bottomed right there today... keeping us guessing a bit longer... ;-)
Lastly, and as said, triangles can even have nine legs... so although at this stage I don't find that pattern very likely, we should simply be aware of that option and keep it in mind until disproved.