JP Morgan has dropped its bullish stance on stocks for the next few weeks, a warning for traders but not a recession call.

• The bank sees only a small chance of recession and says the economy is still strong.
• The worry is the Fed: nobody wants to take on risk before the September meeting, with a possible rate hike hanging over it.
• Broadcom's earnings are the week's big test after its stock fell hard following the last report.
• A wave of new company debt and IPOs right after Labor Day could soak up money and press stocks lower.
• September is historically the worst month for the S&P 500, while the fourth quarter is the best.

Outlook: The next few weeks look choppy, but the setup after the Fed meeting and the midterms leans bullish.