* LME metals extend mammoth overnight gains ahead of US data
* Shanghai copper and zinc limit up after LME rally
* Tin bounces almost 50 pct in less than a week
* Markets may have bottomed, risk starting to favour longs
By Nick Trevethan
SINGAPORE, Oct 30 (Reuters) - London copper futures rose almost 2 percent on Thursday, extending Wednesday's 12.6 percent surge, while Shanghai copper and zinc surged by their 4 percent upside limit, chasing the sharp rally in international prices.
London futures reversed early losses to revive their longest string of gains since June. Sentiment was supported by continuing dollar weakness, with the greenback posting its biggest one-day fall in 23 years against a basket of currencies after the Fed delivered an expected 50 point rate cut and China's central bank also cut rates.
Direction later on on Thursday is will be geared towards U.S. third quarter GDP data, seen falling by 0.5 percent versus a 2.8 percent rise in the second quarter, and how equity markets react.
"Direction will be determined by equities, the dollar and all the usual financial market factors that have been driving this," a dealer in Singapore said.
"But the risk now seems to favour being long rather than short. However we are not yet putting on any big directional positions."
London Metal Exchange copper MCU3=LX for delivery in three months rose 1.9 percent, or $90, to $4,745 a tonne by 0702 GMT, adding to Wednesday's $525 gain.
Prices have risen around 26 percent so far this week and if the market can maintain those gains, copper is set for its biggest weekly rise on record. Despite that, for the month, prices are still down 25 percent, which would be their biggest fall in at least three decades.
For a chart detailing monthly metals prices changes click: here
"The down move has to bottom out at some point. We have seen some real lows tested -- our bottom for copper is around $3,500 to $4,000," MF Global analyst Edward Meir said.
On Monday, prices dipped to $3,590, their weakest for more than three years.
"The decline may have ended and we are set for a period of sideways trading in 2009, much as we saw at the start of the century," Meir said.
Shanghai copper futures SCFc3 rose by their 4 percent threshold to 33,100 yuan ($4,838) and zinc SZNc3 also topped out at its limit, at 9,515 yuan, after London zinc jumped almost 10 percent.
LME tin MSN3 rose $25, or 0.2 percent, to $15,250. Tin prices are up almost 50 percent since plunging to a 21-month low of $10,300 on Oct. 24.
"Tin is doing very well. Stocks are dropping, and the market is very dependent on a single producer, Indonesia, which has said it will cut production when prices fall below $15,000," Meir said.
In contrast to most other metals, tin stocks have fallen steadily during 2008. LME inventories of the metal, which is seeing rising demand as a replacement for lead in electrical solder, have dropped 75 percent since August last year to 3,815 tonnes.
By contrast, copper stocks have risen 78 percent in the same period. Metals prices ar 0702 GMT Metal Last Change Pct Move End 2007 Pct chg 08 LME Cu 4745.00 90.00 +1.93 6670.00 -28.86 SHFE Cu* 33100.00 1280.00 +4.02 56880.00 -41.81 LME Alum 2185.00 34.00 +1.58 2403.00 -9.07 SHFE Alum* 14455.00 260.00 +1.83 18180.00 -20.49 COMEX Cu** 203.85 -4.20 -2.02 304.10 -32.97 LME Zinc 1255.00 -5.00 -0.40 2370.00 -47.05 SHFE Zinc 9515.00 290.00 +3.14 18950.00 -49.79 LME Nickel 13400.00 -240.00 -1.76 26350.00 -49.15 LME Lead 1600.00 20.00 +1.27 2550.00 -37.25 LME Tin 15250.00 25.00 +0.16 16400.00 -7.01 LME/Shanghai arb^ 4872 Dollar/yuan 6.8397 \ 6.8400 ** 1st contract month for COMEX copper * 3rd contact month for SHFE aluminium, copper and zinc ^ LME 3-m copper in yuan, including 17 pct VAT, minus SHFE third month (Reporting by Nick Trevethan; Editing by Clarence Fernandez)