* Trade surplus of 2.9 bln Sfr in Nov
* Exports rise, driven by chemicals and pharma
* Machinery and electrical goods back in positive territory (Adds details, analyst comment)
ZURICH, Dec 20 (Reuters) - Swiss exports grew robustly in November as strong sales to the United States and parts of Asia helped offset more muted growth in its biggest trading partner Europe, suggesting firms are weathering the effects off strong Swiss franc.
Exports from Switzerland rose by a real 4 percent year-on-year in November to 18.776 billion Swiss francs, the Federal Customs Office said on Thursday.
"It's another strong number and the best of the year so far, suggesting the Swiss economy remains resilient to the ongoing problems seen in the euro zone," said Tony Nyman, an analyst at Informa Global Markets.
Swiss exports have been helped by a cap the central bank imposed on the soaring Swiss franc at 1.20 to the euro in 2011, but have faced a further handicap from sluggish demand in neighbouring Europe.
Despite faster-than-expected growth in the third quarter, the Swiss National Bank said last week it expects growth to significantly weaken in the final three months of the year as the global economy stays fragile.
But Thursday's number shows demand for Swiss goods is holding up, with exports of chemicals and pharmaceuticals rising a real 11.1 percent, while sales abroad in the machinery and electronics industry were in positive territory for the first time in 16 months.
"The data give the impression that we have passed the trough and confirms our prognosis that exports will once again start contributing to Swiss growth in 2013," said Claude Maurer, head of Swiss economic research at Credit Suisse.
"There are two reasons for this: by keeping the 1.20 lid on the franc, the currency is depreciating in real terms, and secondly the situation in Europe is tentatively improving."
A raft of recent data has also pointed to a rosier outlook for the Swiss economy. Investor sentiment in December rose to its highest level in seven months, while November industrial production grew at a rate not seen since early 2011.
Sales to Asia increased by 8.7 percent and to the United States by 21.3 percent in November.
This compared to a 1.1 percent rise in sales to the European Union, with export growth held back by declining exports to Italy - the country's second-biggest trading partner within the bloc - which tumbled 11 percent.
Growth of exports of Swiss watches, for a long time the most resilient of Swiss industries, slowed to a real 2.9 percent in November, far below the average yearly trend of 8.4 percent.
Overall Switzerland ran a merchandise trade surplus of 2.946 billion Swiss francs in November, the second highest monthly surplus ever registered.
At its quarterly policy review last week, the SNB forecast growth in the region of 1-1.5 percent next year, at the upper end of most analysts' forecasts. (Reporting by Caroline Copley and Martin de Sa'Pinto; editing by Chris Pizzey, London MPG Desk, +44 0 207 542-4441)