* Steel demand to drop because of expected snow
* Smog warnings to shut sintering, furnaces in Tangshan
* Central bank drains 130 bln yuan on Thursday (Updates closing prices)
BEIJING, Jan 4 (Reuters) - China's steel rebar futures fell on Thursday, breaking a three-day rising streak, on concerns of waning demand in the construction sector because of snow forecasts in the northern part of the country.
Cold weather is expected to hit regions across China in the coming week, bringing snow and rain that may cause disruptions at construction sites, one of the biggest consumers of steel.
"In the coming week, temperatures will continue to drop across the country with frequent snow and rain, hitting demand from downstream users, especially demand for construction steel products," said analysts at CITIC Futures in a note in Mandarin.
The most-active construction steel rebar on the Shanghai Futures Exchange SRBcv1 closed 0.7 percent lower to 3,819 yuan ($587.15) a tonne on Thursday.
Spot steel slipped 0.12 percent to 4,471.41 yuan a tonne on Wednesday, consultants Mysteel reported on its website.
Demand for iron ore was set to decline as pollution warnings will lead to steel plants shutting down some units that process the ore before the smelting process.
China's biggest steel-making city of Tangshan issued a second-level pollution alert effective starting on 8 a.m. on Thursday, the city government said. Steel mills were ordered to cut some sintering and shaft furnace production.
Other sectors, including construction and transportation, will be affected by the warning as well. most-active iron ore contract on the Dalian Commodity Exchange DCIOcv1 bounced back from a dip during early trade, rising 0.5 percent to 543.5 yuan a tonne.
Iron ore for delivery to China's Qingdao port .IO62-CNO=MB rose 0.26 percent to $74.97 a tonne on Wednesday, according to Metal Bulletin.
Steel markets were also likely pressured by the Chinese central bank's decision to keep open market operations closed for a ninth straight day on Thursday.
The closure will drain 130 billion yuan ($19.98 billion) from the country's money markets. = 6.5043 Chinese yuan)