The indices had an up-session, and they came back from early losses with a strong afternoon rally. But the underlying technicals were not very encouraging.

The day started out with a slight move up off the opening, and then a quick downside follow-through to yesterday afternoon’s sharp sell-off. They tried a rally that failed at resistance right at the intraday moving averages, and then in early afternoon they sold off with the NDX and the S&P holding near the morning lows, creating double bottoms. That spurred a very sharp afternoon rally that saw the NDX jump about 20 points and the S&P around 9.

In the last hour they pulled back in an orderly fashion, held support and bounced late in the session, with the Dow on the day closing at 13,136, up 73 Ã,¼. The S&P 500 was up a little less than 4 points, closing over 1486, and the Nasdaq 100 up about 5.68, at 1873.43. The Philadelphia Semiconductor Index (SOXX) gained 1.19 today.

Advance/declines were ahead by less than 300 issues on New York, and negative by 80 issues on Nasdaq. Up/down volume was 9 to 7 positive on New York, and 12 to 11 negative on Nasdaq. Total volume on New York was about 1 2/3 billion, and on Nasdaq a little more than 2 1/3 billion, heavy volume there.

TheTechTrader.com board was mostly lower; however on the plus side there were a couple outstanding gainers. Sigma Designs (SIGM) on some upgrades was up 1.32 on nearly 2 million, and Dendreon (DNDN) snapped back 1.14 on 18 3/4 million. Those were the only point-plus gainers on my board.

On the downside, Jones Soda (JSDA) was down 1.45 on nearly 4 million shares. JA Solar (JASO) was down 1.47 on 2 Ã,¾ million, DXP Enterprises (DXPE) off 1.32, and Metabolix (MBLX) down 1.19. Those were the point-plus losers.

Other stocks of note, SunOpta (STKL) dropped 98 cents. Also in the solar group, Solar Fun Power (SOLF) was down another 50 cents, Energy Conversion Devices (ENER) also 50 cents and Evergreen Solar (ESLR) 41 cents.

IDM Pharma (IDMI) gave back 66 cents, USA Technologies (USAT) also gave back 66 cents, and Chindex (CHDX) 61 cents. Taser (TASR) had a strong session, closing at 9.10, up 47 cents on 3.9 million.

Stepping back and reviewing the hourly chart patterns, the indices this morning continued yesterday’s sharp loss but stabilized mid-day and rallied in the afternoon to snap back. But they failed to take out key overhead resistance at S&P 500 1490 and NDX 1880. Those are the levels we’ll be keeping an eye on tomorrow for overhead resistance.

Today’s lows at 1857 NDX and 1477 S&P look to be key short-term support, and if taken out tomorrow could lead to substantially more selling.

Harry Boxer is a technical consultant to many Wall Street hedge funds and large institutional traders, and author of TheTechTrader.com, a real-time diary of his day, swing and intermediate-term trades. For more of Harry Boxer, sign up for a free 15-day trial to his Real-Time Technical Trading Diary, or sign up for a free 30-day trial to his Top Charts of the Week service.