UPDATE 3-Lotos sees weaker Q4 after Q3 beats forecasts

* Q3 net profit 579.4 mln zlotys vs yr-ago 237.9 mln loss

* Beats market forecasts for 386 mln zloty profit

* Shares rise 1.6 percent

(Adds quotes, forecasts, updates share price)

By Patryk Wasilewski and Pawel Bernat

WARSAW, Nov 5 (Reuters) - Poland's No. 2 refiner Lotos LTOS.WA says earnings are likely to drop back in the fourth quarter after a better-than-expected swing back to profit in the previous quarter.

The third-quarter net profit was helped by gains on foreign currency-denominated loans and higher oil prices that boosted inventory values.

However, Chief Finance Officer Mariusz Machajewski expects the positive effect of the stronger zloty to dissipate in the fourth quarter, while operating profit will be hit by usual seasonal factors.

"On the net level we will see totally different numbers, as there will be no debt adjustment. Operationally it might be slightly weaker as the third quarter is the best season and the macro conditions do not improve," Machajewski said.

A firmer zloty helped Lotos book more than 500 million zlotys in third-quarter earnings on financial operations, as this cut the value of its foreign currency-denominated loans.

Lotos, like most refiners across the globe, struggled with weak refining margins in the quarter, which dropped 69 percent year-on-year.

Additionally the Ural/Brent differential, a spread between Ural oil used as feedstock by the refiner and Brent oil, which forms the benchmark for its sales, dropped 82 percent.

Chief Executive Pawel Olechnowicz warned the low refining margins were unlikely to improve next year, and refiners would have to adjust to the poor market conditions.

"We have to get used to it (poor conditions) and learn how to operate with refining margins at about $2 - $2.8 per barrel," he said.

Lotos' third-quarter net profit was 579.4 million zlotys ($200 million) versus a year-earlier loss of 237.9 million zlotys, well ahead of analysts' forecasts for a 386 million zloty profit.

The refiner surprised with very high refining volumes of 2.1 million tonnes and 101 percent utilisation of refining capacities in the third quarter.

"Despite unquestionably poor refining macro conditions during three quarters, operating cash flow is striking," BZ WBK analyst Pawel Burzynski said. "Lotos bridged a profitability gap by higher volumes."

Lotos shares, which more than doubled this year, rose as much as 3 percent in early trade but trimmed their gains to 1.6 percent in the afternoon, slightly outperforming Warsaw's main index WIG20 which gained 0.9 percent. ($1=2.894 Zloty)