新华社北京７月２１日电（记者李志勇、张淼淼）２１日１０时起，北京迎来降雨，１４时许，局部地区降雨量已达暴雨级别。北京市气象台１４时将上午发布的暴雨蓝色预警升级为黄色，２０分钟后，又发布了雷电黄色预警。

    Beijing, July 21 dec（Reporter LiZhiYong、ZhangMiaoMiao）21, when the 10，Beijing Saturday as rainfall，At about 14，Local area rainfall has reached a level of heavy rain。The Beijing meteorological offices will be released in the morning of the early warning for yellow rainstorm blue upgrade，After 20 minutes，And issued a warning of the lightning yellow。

    北京市气象台１４时发布的暴雨黄色预警称：预计门头沟、通州，以及城区大部分地区未来３小时雨强将超过３０毫米／小时。１４时２０分，北京市气象台又发布雷电黄色预警：受雷雨云团影响，预计未来１２小时内北京大部分地区有雷电天气，请市民注意防范。

    The Beijing meteorological station when the heavy rain released 14 yellow warning says：Men-tou vallely is expected to、tongzhou，And much of the city over the next three hours in the rain strong to more than 30 mm/hour。14 when 20 points，Issued by the Beijing meteorological offices and lightning yellow warning：Thunderstorm influence by clouds，The expected future 12 hours in most parts of Beijing lightning--the weather，Please pay attention to the prevention citizens。

    从１０时开始，北京主城区已出现明显降雨，天空中云层很厚，天色黯淡如黄昏。记者在天安门广场南面看到，降雨量逐渐增加，至１４时左右已成瓢泼大雨，游客行人打着伞也被雨水淋湿，纷纷到附近的商店躲雨。前门大街上，汽车的雨刮器也开到了最快一挡。

    Begin from 10，Beijing city already apparent rainfall，Thick clouds in the sky，It was dark as dusk。The reporter saw south in tiananmen square，Rainfall to increase gradually，To 14 at around has already become the raining cats and dogs，Visitors an umbrella was also the rain the wet，In to the store close to shelter from the rain。Qianmen street，The car pulled up to the fastest and wiper a block。

    记者从北京市气象台了解到，２１日的降雨是北京迎来主汛期后的第一场暴雨，成因主要是受东移南下的冷空气和西南暖湿气流的共同影响。同时，降雨将伴有雷电、短时大风等强对流天气。１０时左右，河北西北部有雷雨回波发展东移，逐渐进入北京西南部地区。截至１４时，北京海淀西部、房山、门头沟、延庆、昌平出现明显降雨，西南部地区平均降雨量为５０．１毫米，最大降雨量出现在门头沟区的龙泉地区，达到１１７．８毫米，城市中心区降雨量为２９．９毫米，全市平均降雨量为１９．４毫米。

    Reporters from the Beijing municipal offices to understand，21 days of rain is in Beijing ZhuXunQi after the first storm，Main causes is affected by the south towards the east and southwest of cold air warm-moist air flow common effect。At the same time，Rainfall will be accompanied by thunder、Short-term winds and strong convective weather。At about 10，There's a thunderstorm northwest hebei echo development towards the east，Entering the southwest of Beijing。By the，Beijing haidian western、Fang shan magmatic、Men-tou vallely、yanqing、There is a clear sense of rainfall，Southwest average rainfall is 50.1 mm，The biggest rainfall appears in the mentougou district longquan area，117.8 mm，City center rainfall is 29.9 mm，The average rainfall is 19.4 mm。

    针对这次暴雨天气，北京市气象局启动四级应急响应，各相关单位和部门已进入应急响应状态，加强应急值守和各项服务保障工作。至１５时左右，天安门等城市核心区降雨量已转小，莲花桥等部分易积水路段出现短时积水后，被排水集团值班工人迅速排干，市区交通通行情况正常，降雨仍在持续中。

    In light of the torrential rain，The Beijing meteorological bureau start level 4 emergency response，The relevant units and departments has entered the emergency response state，Strengthen the emergency services need and security work。To 15 at about，Tiananmen etc area of the city rainfall has to turn small，Lotus bridge part such as easy seeper sections appear after the short water，Be drainage group on duty workers quickly drained，Urban traffic condition normal，Rain still continues。