气候预测中心新一期展望：下周末大气河可能影响西海岸 加州北部中部强降水风险达四至六成
美国国家气象局气候预测中心（Climate Prediction Center，CPC）11 月 6 日发布新一期第二周灾害展望，有效期为 11 月 14 日至 20 日；同日更新的 CPC 关键信息指出，一次大气河活动可能影响美国西海岸各州。
按这期展望，11 月 14 日至 15 日，俄勒冈州西南部部分地区以及加利福尼亚州北部和中部出现强降水的风险为中等，概率 40% 至 60%；强降水的轻微风险（20% 至 40%）延续到 11 月 17 日，范围覆盖西海岸并延伸到西南部、大盆地和落基山脉南部。
高海拔降雪方面，11 月 14 日至 15 日，Klamath 山脉和内华达山脉（Sierra Nevada）高海拔地区出现大雪的风险为中等；到 11 月 17 日，喀斯喀特山脉、Klamath 和内华达山脉，以及北部山间地区、大盆地和落基山脉中北部的部分高海拔地区，存在大雪的轻微风险。
CPC 预报员 Thomas Collow 在展望说明中指出，欧洲中期天气预报中心、美国全球集合预报系统和加拿大集合预报持续显示美国西海岸外海有异常低压槽发展，水汽输送增强是这期展望提高西海岸强降水与高山大雪风险的主要依据。CPC 在关键信息中提示，公众应关注本地天气预报和安全警报，不要驾车穿过被水淹没的道路，经过高海拔地区时注意安全。
New CPC Outlook: Atmospheric River May Affect the West Coast Next Weekend, With a 40–60% Risk of Heavy Rain for Northern and Central California
The National Weather Service Climate Prediction Center (CPC) issued a new Week-2 hazards outlook on November 6, valid for November 14 to 20, and its updated key message the same day said possible atmospheric river activity could affect West Coast states.
According to the outlook, parts of southwest Oregon and northern and central California face a moderate risk of heavy precipitation on November 14 and 15, with probabilities of 40 to 60 percent. A slight risk of heavy precipitation, at 20 to 40 percent, extends through November 17 across the West Coast and into parts of the Southwest, the Great Basin and the Southern Rockies.
For high-elevation snow, the Klamath Mountains and the Sierra Nevada face a moderate risk of heavy snow on November 14 and 15. Through November 17, a slight risk of heavy snow covers high elevations of the Cascades, the Klamath and the Sierra Nevada, as well as parts of the Northern Intermountain, the Great Basin and the Central and Northern Rockies.
Forecaster Thomas Collow wrote in the outlook discussion that the ECMWF, GEFS and Canadian ensembles continue to depict anomalous troughing off the West Coast, with a potent surge of moisture at the start of the period keeping risks elevated for heavy precipitation, high-elevation snow and coastal winds. In its key message, the CPC advised the public to monitor local forecasts for safety alerts, avoid driving through flooded roadways, and use caution when traveling through high elevations.
来源：美国国家海洋和大气管理局
发布：GSM·美国（发布链接）
图片来源：图：加利福尼亚州内华达山脉的雪峰。Quintinsoloviev 摄，CC0，经 Wikimedia Commons。 / Photo: Snow-capped peaks of the Sierra Nevada in California. By Quintinsoloviev, CC0, via Wikimedia Commons.
GSM Global · 本篇英文版 English edition of this story
